Across high‑risk markets, response teams confront fresh tamper tactics, and a newly introduced secondary locator from Queclink Wireless Solutions counters them. From a worldwide technology partner comes a discreet companion edge tracker that lifts retrieval rates by outsmarting sophisticated thieves in challenging conditions for telematics deployments.

Built for layered protection, the compact module stays dormant for long standby windows and can be tucked out of sight as a low‑profile safeguard, drawing on an internal battery. As a covert secondary locator that complements the main unit, the product is designated GL51CG.

Criminal groups have learned to hunt for obvious, hard‑wired boxes, which makes single-device installs increasingly easy to defeat, says Vernon Bonser, International Sales Director at Queclink Wireless Solutions. Since fewer than one in five cases end with a find, our focus is on uninterrupted tracking plus rapid loss alerts, so insurers, lenders, and security‑led telematics operators can raise their success rate.

Hidden almost anywhere within the cabin or chassis, the tiny 58×57×26 mm enclosure stays asleep until it no longer detects the hardwired peer. Using BLE 5.4 to watch that link, it switches itself on when the tether is cut and begins independent tracking with real-time position reporting. In common deployments, the main box communicates through cellular networks such as LTE, often via LTE Cat profiles, and the backup companion preserves continuity if the path is blocked. A long‑life power pack supports operation for as long as six years.

Articles

Queclink Wireless Solutions Driving Smarter Iot For Theft Recovery

For crews flying survey planes, an advanced medium format system now targets under‑one‑centimeter detail. With this release aimed at national survey programs and linear work, Phase One brings the iXM‑FS130 to market to achieve true 1 cm GSD from quick‑cruising fixed‑wing planes.

For established users, the underlying architecture remains familiar, while a hybrid shutter debuts to open fresh mission profiles and preserve tooling and processes. Suited to seasoned crews and to high‑value geospatial programs, the system serves fixed‑wing fleets and sets a new bar for nationwide mapping, corridor surveys, and defense‑grade imagery.

Sub-Centimeter GSD at Speed, Without Compromises

Even above 120 knots, crews can lock in dependable 1 cm ground resolution, so each sortie spans more terrain for aerial work. Tasks once limited by smear, overlap margins, or the fear of flying again become achievable in a single pass. By pairing ultra‑fast exposures with a motion‑neutral capture path, the iXM‑FS130 pushes throughput higher while trimming flight time and operating spend.

Fusion Shutter Technology for Motion-Free Imaging

At the heart of the design is a patented Fusion Shutter from Phase One, blending a global electronic array with a leaf‑type mechanical unit. This hybrid approach blocks PLS artifacts even during ultra‑short exposures, preserving clean, high‑contrast aerial image data. Because data remain uniform across challenging light, teams obtain consistent, survey‑grade results in one pass, cutting weather delays, risk, and re‑flights.

Phase One Unveils Ixm-fs130 For True 1 cm Gsd

Earlier this week, Veesus introduced Arena4U, an approachable system for exchanging project data that keeps teamwork straightforward, transparent, and free from hidden fees. Built for teams that need to share updates without friction, the release reflects Veesus’s focus on practical tools rather than buzzwords.

To suit varied IT policies, the service can run on company hardware or be hosted in the cloud, cutting friction for exchanging information and collaborating in real time, which notably enhances how users handle intricate 3D initiatives.

Rather than wrestling with risky handoffs, teams can bring all project materials together inside Arena4U alongside existing viewers, so every participant consults a single authoritative view. When appropriate, people may receive view-only rights that stream point cloud scenes and other large assets without any file copies. For threaded teamwork, notes and messages are built in, enabling secure remote discussion.

From a budgeting standpoint, running Arena4U on servers you control can avoid the relentless storage and processing fees associated with massive datasets in hosted infrastructure. For many organizations, keeping workloads on premises delivers sizable savings compared with the recurring charges of conventional cloud offerings.

Across many collaborative teams, link-passing by email becomes chaotic: messages get buried, and temporary addresses lapse. By folding external addresses into one Arena4U workspace, participants can explore varied sources from one place without hopping between tabs.

Introducing Arena4u For Collaboration

Across England, new homes, clinics, and learning spaces are made possible by precise mapping of terrain and features. Before designs appear on screen, teams lean on an early-stage topographical survey to capture land form, heights, and restrictions, turning raw ground into reliable context for delivery. Only after that baseline exists do schedules and budgets stabilize.

During the 2025 fiscal update, ministers outlined roughly 250 new clinics for neighbourhoods together with major programmes to renew and modernize schools. Additional ring‑fenced finance supported renewal programmes and work on previously developed land for residential needs, sharpening attention on placing the right asset in the right location at pace, with safety and durability in mind. Together, the measures signal a broader turn toward place‑based investment and joined‑up public services.

Why Early-Stage Site Intelligence Matters

From an environmental risk perspective, the demand for reliable ground truth has never been higher, according to specialists at Lucion Group (Ltd). With schemes leaning toward local provision, choices increasingly rest on granular field information that enables smarter trade‑offs.

Right at kick‑off, terrain and feature capture frames the brief, then guides concept work, approvals, and construction sequencing while shrinking risk exposure. This dataset, built to survey‑grade standards, supports each step from outline thinking to delivery on site. Digital coordination, including BIM, performs better when the base map is both complete and dependable.

Evidence-Led Design for Tight and Complex Sites

For schemes in health, education, and residential programmes, the team at Lucion supplies future‑ready files that let decision‑makers justify options with evidence, especially where plots are tight or complicated. Where previously developed land demands careful interpretation, clarity arrives through detailed site measurement, including a topographical survey that reveals levels, utilities, and constraints so layouts can be tested and refined early.

Every parcel brings its own quirks, noted Will Vennard, Business Unit Director at Lucion Surveying & Geospatial. By quantifying heights, boundaries, and structures early, teams can commit to options with confidence; without that baseline, minor drafting mistakes can snowball into major delays.

Healthcare: From Mega-Hospitals to Local Hubs

In the current model, smaller neighborhood clinics are preferred over large hospital megaprojects, and that pivot introduces fresh complications. Numerous candidates occupy tight inner‑city footprints, reclaimed plots, or settings embedded in lived‑in communities.

With sites like these, detailed mapping provided by the team at Lucion helps teams understand perimeters, entrances, adjacent buildings, and level changes in detail. This depth of knowledge streamlines approvals and reduces rework later in the timeline. Better early data often shortens pre‑construction stages and reduces disruption for neighbours.

Topographic Surveys Power Local Health, Education, And Housing

In a strategic leadership move, the company has named researcher‑engineer Pawel Michalak as its new technology chief to steer the next stage of its technology roadmap at Advanced Navigation, with a mandate centered on autonomy.

Given mounting pressure on location methods amid hostile weather, jamming, and the demands of abyssal and orbital operations, sole dependence on GPS or other GNSS constellations is buckling across defense and commercial use.

Under his remit, the organization will pivot toward a stack for position, navigation and timing designed for resilience, ensuring guidance even when any single feed becomes unavailable. To make that shift real, European hiring will scale engineering capacity and unlock fresh navigation technology for hostile theaters.

Pawel Michalak Appointed Chief Technology Officer

From the vantage point of CEO Chris Shaw, once it was acceptable to trust only satellites, yet modern navigation systems must assume irregular signals as routine and build autonomy accordingly with AI in the loop.

He emphasized that new architectures and unconventional thinking are required so research can become production-grade breakthroughs at speed.

AI and GPS-Resilient Architectures for Autonomous Systems

To move this vision from lab to line, Michalak will champion an inertial‑first framework that fuses cues from inertial navigation, advanced photonic techniques, and robotics to create a neural‑like layer for self-directed platforms across sea, land, air, and space.

Complementary sources will include quantum sensing modalities, underwater acoustics, and specialized receivers and antennas.

As he notes, true robustness for timing and guidance emerges by blending raw measurements from diverse sensors—ranging from inertial and vision to laser and quantum—so PNT navigation and timing no longer hinge on any single channel.

Advanced Navigation Appoints Pawel Michalak as Cto to Accelerate Autonomy

Looking beyond current missions, the two companies have sealed a deal to distribute data products and software applications derived from the forthcoming PAZ-2 radar satellites, while also deepening their long-running cooperation in the global market for orbital radar sensing.

Radar Satellite Constellation With TerraSAR-X

At a high-profile industry forum in Belgium’s capital, formal steps were taken to prolong the arrangement that enables sales of PAZ observation satellite sensor outputs in combination with Germany’s TerraSAR-X and TanDEM-X spacecraft, a joint setup that has operated since 2018.

Speaking about the plan, Eric Even, a senior leader at Airbus Defence and Space, said the alliance will stretch the state of the art in Synthetic Aperture Radar and bring fresh offerings addressing intelligence and surveillance needs alongside commercial use cases.

In a similar vein, the chief executive, Miguel Ángel García Primo of Hisdesat, said reinforcing the commercial tie-up safeguards the continuity seen since 2018 and will broaden the uptake of SAR outputs—usable in any weather—relative to alternative sensing tools.

Under the guidance of Spain’s defense authorities, a next-generation initiative—known as PAZ-2—ranks among the most advanced orbital monitoring efforts and is carried out with Hisdesat. The effort involves two twin spacecraft that will take over from PAZ—operational since 2018—while boosting capability. Spain’s department responsible for Industry and Tourism provides the financing, and the primary recipient of high-resolution radar imaging and services will be the nation’s defence ministry.

By July 2025, the build contract for the pair of new satellites had been placed by Hisdesat with Airbus Defence and Space.

Airbus And Hisdesat Sign Commercialisation Agreement For Paz-2

Marking a recent milestone in upper‑atmosphere platforms, a solar‑charged craft, ApusNeo 18, carried a new optoelectronic, gimbal‑stabilized sensor pod through evaluation runs. After evaluation concluded, a joint effort delivered a payload that finished trials successfully while operating as an integrated unit on the aircraft—an effort later credited to UAVOS together with Mira Aerospace.

Near 15,000 m, operators recorded scenes spanning 472 km using electro‑optical sensors, producing high‑resolution imagery and delivering a ground sample distance of 69 cm/px; thermal mapping reached 480 cm/px. Each frame covered roughly 53.9 km², and the pointing mechanism offered access to any location within a window of about 54.5 by 12.3 km at will. Purpose‑built for sustained stratospheric duty, the unit boosts ISR roles for HAPS aircraft.

Weighing about 3.6 kg, the compact module measures 845 × 128 × 142 mm. Onboard tasks run on an embedded processor, while the data modem from UAVOS, paired with a 10 W amplifier, supports high‑throughput links to the ground station and services the payload.

Uavos High-altitude Test Flight on Apusneo 18

Backed by cross‑sector research and field feedback, the company Metis today unveils Skyperion Lightweight, a new RF‑based detection product for aerospace and security operators focused on drone awareness.

For squads that must move fast, this compact variant preserves almost the entire detect–track–identify DTI sensor suite of its highly regarded sibling, Skyperion Rugged, yet trims SWaP—size, mass, and power draw—for rapid set‑up while maneuvering. As a result, teams gain a mobile C‑UAS option tuned for quick deployment and sustained patrols. Teams can carry it with minimal burden, keeping power draw and weight low without trading away performance. During daily operations, field crews benefit from a balance of portability and endurance.

Across a ten‑year span, leadership in passive sensing for C‑UAS has seen Metis contribute the DTI module to the RAF’s ORCUS and to Leonardo’s Falcon Shield. Working alongside NATO allies, these programs secure airspace and key facilities through precision drone detection and early warning. Together, they deter hostile unmanned incursions around vital assets. Across the product line, receivers collect radio emissions at multiple strengths, discard background clutter and whitelisted signals, and rapidly analyze the remainder to pinpoint probable threats.

Metis Launches Skyperion Lightweight For Mobile C-uas Capability

Does it matter whether public-oriented decision processes and outcomes are transparent, accountable and fully informed? Participatory decision making is as old as democracy.From national elections to local land-use planning, participatory decision making exemplifies the democratic maxim that those affected by a decision outcome should participate directly in decision processes.

For years, a GIS has been called a decision support system (Cowen 1988).When we connect GIS with participatory contexts we get "participatory GIS," (PGIS) (Harris et al.1995, Jankowski and Nyerges 2001) or a "public participation GIS" (PPGIS) (Nyerges, Barndt, Brooks 1997), or community integrated GIS (Craig, Harris, and Weiner 2001). The term public is defined by the American Heritage Dictionary Fourth Edition as "the community or the people as a whole or alternatively a group of people sharing a common interest as in the reading public.The term participation is defined as the act of taking part or sharing in something." Given that the term public is an adjective qualifying participation in PPGIS, the term PGIS is actually the broader, more inclusive, of the two phrases - although some researchers prefer to restrict use of "PGIS" to participatory development within developing countries. In the late 1990's, the phrase "community integrated GIS" became preferred to refocus research effort on community (Craig, Harris and Weiner 2001).Whether we use "participatory" or "public participation" or "community integrated" does not matter, as public is commonly constituted of diverse groups with varying interests.

Regardless of the label, individuals as part of the public and groups within the public are often marginalized in public decision processes. Groups/communities traditionally marginalized, i.e., under-represented in decision processes at macro scales, are now organizing with the help of action research projects.For example, within the City of Milwaukee, in a project called Making Connections, residents helped with GIS maps to form a story about community development potential.In another example, drawing on local knowledge of indigenous peoples, participatory 3D modelling helps visualize landscapes for protected area management in Southeast Asia.In a third example, local knowledge from Native American tribes is sensitive to tribal cultural history.Unfortunately, GIS data recording of such knowledge could be exploited for development purposes and/or to protect culturally sensitive sites.In the studies above, as well as in most PPGIS activities, participation focuses on smaller groups rather than larger groups.

When examining an ability to give the public a voice in democracy, marginalized voice is a fairly pervasive problem.Practically speaking, the general public is constituted of many diverse groups - even if we consider the public as a whole.The general public is actually a marginalized group when it comes to participation processes, as there is no single, directed voice in the public.

Despite many federal, state and local laws that require public participation, research about local governance indicates that large-group participation in publicly oriented decisions commonly involves little meaningful participation.Meaningful participation can be defined in terms of access to voice (a deliberative process) and competence of knowledge(s) (an analytic process) that fosters shared understanding about values, interests and concerns that underlie the recommendations/choices to be offered/made by those with a stake in the decision (National Research Council 1996). Meaningful participation is a hallmark of a healthy democracy, particularly deliberative democracy in contrast to representative (make a vote) democracy.

Deliberative democracy involves empowerment wherein a reasoned discussion among people promotes shared understanding on a topic followed by consensus building.Although interest in deliberative democracy has existed for over 100 years (Gastil and Levine 2005), research and practice has blossomed since the late 1980's.Over the past decade, hundreds of deliberative democracy events of varying sizes have occurred across the world.A synthesis of case studies appears in a Deliberative Democracy Handbook (Gastil and Levine 2005).Several of the chapters deal with location-based issues, and thus GIS could be useful.However, no chapters actually refer to GIS, a seeming disconnect and latent opportunity.Of special note, some deliberative events have involved thousands of people at once.In 2002, AmericaSpeaks, a not-for-profit organization located in Washington D.C., organized a 21st Century Town Meeting at the Javitt's Center in New York City that brought together more than 3,000 people to discuss redevelopment plans for the World Trade Tower site after September 11, 2001.Unfortunately, such activity comes at great expense, requiring hundreds of facilitators at multiple levels of responsibility.

Research about analytic-deliberative decision processes has shown that meaningful public participation is possible and decision outcomes are improved (National Research Council 1996).The analytic component provides technical information that ensures broad-based, competent perspectives.GIS has provided technical information in such processes as maps can represent changes in landscapes.The deliberative component provides an opportunity to give voice to choices about values, alternatives and recommendations. Unfortunately, such public participation has been expensive and time consuming, and involved small to medium-sized groups (10-15 people). Working through analytic-deliberative participation in small to medium-sized groups in face-to-face settings is a start, but scaling analytic-deliberative participation to large groups is a challenge - as scale matters.

In addition, whether groups are better supported in face-to-face settings or in asynchronous settings is still an open research question.It is often thought that face-to-face participatory settings are superior to asynchronous participatory settings.It only seems reasonable.However, Dowling and St.Louis (2000) have shown that an asynchronous nominal group process was more effective than a face-to-face nominal group process, at least in a small group setting - a challenge to anecdotal feelings about face-to-face participatory processes.

Based on the following three observations: (1) public participation is mandated by many federal, state and local laws encouraging core democratic process; (2) the Internet is growing in popularity and access is getting better even for under-represented groups as reported in several studies; and (3) asynchronous, structured participation methods have been shown to be at least as good and in some cases superior to face-to-face participation; perhaps an Internet platform combining GIS (i.e., data management, spatial analysis and geovisualization) technologies, decision modeling technology, and communications technology into a geospatial portal to support an analytic-deliberative process might be one way to foster meaningful participation in large groups as well as hold down the cost to all who wish to participate.This rationale is the basis of the US National Science Foundation-funded research activity called the Participatory GIS for Transportation (PGIST) Project.The principal research question for the project is: What Internet platform designs and capabilities, particularly including GIS technology, can improve public participation in analytic-deliberative transportation decision making within large groups?

Addressing that question involves intensive interdisciplinary work. From experience on several large interdisciplinary projects over the past decade, getting researchers to work with one another has been equally as challenging as getting stakeholders to work together.The commonality of that challenge and the one for analytic-deliberative public participation involves resolving mismatch of language meanings, e.g., the meaning of transportation-based valued-concerns. Computer-supported resolution of mismatched meanings among many people is at the core of the grand challenge.Certainly, this essay is not the first to recognize this challenge.Other literature, e.g., dealing with boundary objects in science and technology studies, recognize a similar challenge.The difference here, however, is in recognizing that scale really matters, and is particularly constraining when working in a computer-mediated setting.For those who see the World Wide Web as promoting anytime, anywhere and anytime work, it just isn't so as yet in connection with analytic-deliberative work at large, participatory scales - what just might be considered a grand challenge for PPGIS work.

Cowen, D.1988.GIS versus CAD versus DBMS: what are the differences? Photogrammetric Engineering and Remote Sensing, 54, 11, 1551-1555.

Craig, Will, Trevor Harris and Daniel Weiner (Editors) (2001) Community Participation and Geographic Information Systems. Taylor and Francis.

Dowling, K.L.R.D.St.Louis 2000.Asynchronous implementation of the nominal group technique: is it effective? Decision Support Systems 29:229:248.

Gastil, J and P.Levine 2005.The Deliberative Democracy Handbook.San Francisco: Jossey-Bass.

Harris, Trevor M., Weiner, Daniel, Warner, Timothy A., and Levin, Richard.1995.Pursuing social goals through participatory geographic information systems.Redressing South Africa's historical political ecology.In Pickles, J., ed., Ground Truth: The Social Implications of Geographic Information Systems. New York: Guilford Press.196-222.

Jankowski, P.and Nyerges, T.2001.Geographic Information Systems for Group Decision Making: Toward a Participatory, Geographic Information Science, London, Taylor & Francis.

National Research Council 1996.Understanding Risk: Informing Decisions in a Democratic Society, Washington, D.C., National Academy Press.

Nyerges, T, M.Barndt, and K.Brooks, 1997. Public Participation Geographic Information Systems, Proceedings, Auto-Carto 13, Seattle, WA, American Congress on Surveying and Mapping, Bethesda, MD, pp.224-233.

Scaling-Up as a Grand Challenge for Public Participation GIS

- The second edition of MundoGEO#Connect, the largest event of the geotechnologies sector of Latin America, has its dates already set: from May 29th to May 31st, 2012, at Frei Caneca Convention Center, in São Paulo (SP). 

From now on, you can follow all of the innovations of the event, through. The portal of MundoGEO#Connect 2012 is a source of information to the event’s participants, press, lecturers and debaters, public bodies, private companies, and all the parties interested in the matters that involve the geospatial industry.   

Reiterating the success of its first edition, which took place from June 14th to June 16th, 2011, MundoGEO#Connect 2012 should gather more than 10 thousand professionals, among those participating in the technical activities and in the trade fair, and those connected through the social nets and online seminars, (about 10% of the event will be broadcast).

Besides, great companies of the sector have already confirmed their sponsorship, such as Hexagon, one of the most important groups of the metrology sector and holder of Leica Geosystems, Erdas, Intergraph and recently of the brazilian company Sisgraph; Furtado Schmidt, representative, in Brazil, of the brands Garmin, Nikon and Spectra Precision; the group Santiago & Cintra, representative of Trimble, Topcon, Faro, Erdas, RapidEye and Navteq; and Alezi Teodolini, representative of Astech and Datageosis.

Other institutions, national and international, are also supporting the event, such as the Brazilian Institute of Geography and Statistics (IBGE), Embrapa, São Paulo Company of Metropolitan Planning (Emplasa), City hall of São Paulo, Geospatial Information & Technology Association (Gita), International Society for Photogrammetry and Remote Sensing (ISPRS) and Open Geospatial Consortium (OGC). 

Having the theme "Sharing information for a better world", MundoGEO#Connect 2012 will highlight the current challenge involved in the production of geospatial data, following patterns that facilitate its full use by the community of users of information systems. 

In this edition, the offer of stands at the fair of products and services of MundoGEO#Connect 2012 was enlarged in 50%. Moreover, the number of auditoriums for the activities of the event was enlarged in 100% in relation to the 2011 event.  

According to Emerson Granemann, director and publisher of MundoGEO Group, the event will hold several seminars, courses and parallel events that will discuss the trends of geoprocessing, remote sensing, surveying, GPS and spatial data infrastructure, in the areas of oil & gas, mining, e-government, agribusinesses, mapping of big cities’ underground, environment, among others. “We have a lot of innovations for this second edition of the event. The MundoGEO#Connect awards will be enlarged in order to choose the best professionals, companies and projects of the year, starting with voting online and the votes from the judging committee." 

Some parallel events are already confirmed: Users of Geotechnologies from the State of São Paulo, Users of Geotechnologies from the Municipal district of São Paulo, National Spatial Data Infrastructure (Inde) and OGC Patterns.  

As in 2011, this year’s edition of the event will also hold the 2nd MundoGEO#Connect Awards, an initiative that recognizes the works developed by companies, institutions and professionals of the geotechnologies sector. 

MundoGEO#Connect 2011: success of audience

MundoGEO#Connect came from the perception of its creators on the subjects that had more repercussion in the main social nets, such as Twitter and Facebook, one of the platforms that provide the most interaction among the people. Thus, one of the objectives of the event is to connect the geospatial technologies users who are present at the event as well as the ones who are online, so that there is the sharing of ideas on the current scenery of the sector. 

In its first edition, MundoGEO#Connect counted on 88% of the sponsors' and participants’ approval, according with a poll on the organization of the event. There were over 7,5 thousand connected professionals: 900 participants of seminars and mini-courses, 1,8 thousand visitors to the fair and more than 5 thousand internet users that followed the event online, through Twitter and through webinars.  

The poll numbers point out that 32% of the participants are directors and 33% are managers or coordinators; 50% come from the private sector and 36% come from the public sector; and that the areas of interest with larger percentages are environment, natural resources, utilities, infrastructure and territorial planning.  

Pablo Santos, who works at the Superintendency of Economical and Social Studies of the State of Bahia, points out that the event provides "a unique opportunity to work, and share experiences with other public or private organizations in relation to the projects that take place in the most diversified Brazilian states".

Furthermore, over 100 lecturers were present at the event, including representatives of international companies, such as the president of Erdas, Joel Campbell. "This is an extremely important event to the geotechnologies market, especially in Brazil, because there are more than 2 thousand people participating, who came from all around Latin America, Europe, Africa, and it is also an important conference where the hardware and software suppliers, the data providers are gathered to share ideas on how they can work together", comments the executive, at an exclusive interview to MundoGEO.   

Among the outstanding people who participated in the event were Tarun Bhatnagar, director of enterprise geo of Google in Latin America, that took part in the 2nd Google Earth for Companies Seminar; Wolfgang Bidermann, businessman from RapidEye; Dale Lutz, vice-president of products development of Safe Software; and Mike Reslow, representative of ISPRS.  

MundoGEO#Connect 2012 is the largest event in the section of geospatial technologies of Latin America and it will take place from May 29th  to May 31st , at Frei Caneca Convention Center, in São Paulo (SP). Holding the theme "Sharing information for a better world", the expectation is to gather 10.000 professionals from the sector, among those participating in the seminars and courses, the visitors of the trade fair and the ones connected from  distance through webinar and social nets. The event is an accomplishment of MundoGEO Group, along with the popularization of MundoGEO and InfoGPS web portals, InfoGEO, InfoGNSS and A Mira magazines, and it also counts on the international support from OGC, ISPRS and Gita, and popularization of Directions Magazine, GIM International, V1 Magazine, Professional Surveyor and Geo Connexion. The first edition of MundoGEO#Connect was held from June 14th  to June 16th, 2011, in São Paulo, and it gathered more than 7,5 thousand people. 

MundoGEO Group, which promotes MundoGEO#Connect, has been working in the production of contents for printed and online media, trade fairs, seminars, courses and webinars in the geoinformation area since 1998. It also publishes two important magazines addressed to the sector: InfoGEO, on satellite images and Geographic Information Systems (GIS); and InfoGNSS, which focus on land surveying and cartography. In this area the company counts on MundoGEO Web Portal, which provides daily content in Portuguese, Spanish and English, and which is a leader in the number of visitors in Latin America. In content partnership with UOL, it acts in the geo mobility area with InfoGPS Portal, which, along with MundoGEO, has over 50.000 registered professionals and more than 10.000 thousand followers in the social nets. In relation to the sustainability area, it maintains the Sustainable Attitude Web Portal, also in partnership with UOL.

MundoGEO#Connect 2012 event counts on global brands as sponsors

The 2016 study has 268 pages, 92 tables and figures. Worldwide drone transponder markets are poised to achieve significant growth with the need to achieve protected airways. The simplest way to protect against mid-air collisions is to require the use of ADS-B transponders on all aircraft. Transponders can turn an uncooperative environment into a cooperative environment. Transponders provide location and positioning information about smart commercial UAS. These UAS have a computer inside, they are easy to fly, remotely maneuverable, have a camera, and contain sensor logic. Smart UAS are evolving computer driven collision avoidance technology making the flying more reliable.

Remote operation occurs in the context of a workflow and sensors. Cameras are improving dramatically to permit management of video and picture taking that is realistic and detailed. Drone actuators, drone transponders, are needed to support drone package delivery. This is a huge new market that speeds economic development, makes it easier for the middle class to both work, and purchase lifestyle items and food efficiently. UAS based on aerial robotic platform technology can be used to make deliveries to each person’s home, landing on the back doorstep, leaving packages in a locked box. The drone package delivery technology has reached a level of maturity that bodes well for market development. Drone systems are mature enough to be at the forefront of aerospace manufacturing. Dronecode is an independently funded software project that harnesses the power of collaborative development. The aim is to fuel innovation across drone industries and ecosystems. Dronecode Foundation is a nonprofit organization working on a common, shared open source platform for Unmanned Aerial Vehicles (UAVs). Dronecode brings together existing and future open source UAV software projects.

APM UAV software platform was developed by 3DRobotics. 1,200 developers are working on Dronecode’s six projects focused on maximizing adoption of the project’s cost-effective, reliable and technologically advanced UAV software. UAvionix has an ultra-lightweight low cost ADS-B transponder for UAS. UAvionix has developed an ADS-B suitable for UAVs of all sizes to improve flying safety for all. The ping™ is a family of ultralight weight, low cost, ADS-B transponders. Weights range from 1.5 to 30 grams, delivering a variety of types of performance. The ping2020™, for instance, is capable of IN on both 1090ES and 978UAT, and OUT on 978UAT. The products are fully compliant with the minimum performance standards of DO-282B Class A1S. UAvionix has developed an ADS-B suitable for UAVs of all sizes to The ping™ is among the world’s first families of ultralight weight, low cost, ADS-B transponders. Transponder and sense and avoid technology sponsorship by Sagetech, L-3 Aviation Products, FreeFlight, UAvionix, Google, Trig, DJI, and Intel has been effective. Development by Dronecode application ecosystem provides huge advances in drone real-time sense and avoid behavior. An open source collaboration is expected to accelerate deployable solutions for agile and reliable operation in the national airspace. The open source platform has been adopted by many organizations on the forefront of drone technology: 3DRobotics, Parrot, Qualcomm, Intel, DroneDeploy, Yuneec, Airphrame, and others. The worldwide market for drone transponders is anticipated to start from nothing and reach $2.5 billion worldwide by 2022 growing in response to the need to prevent drone collisions, keep the highways in the sky safe, and manage routing of commercial UAS. Multiple applications drive market growth, most of all package delivery occurs out of line of sight. Other applications for drone transponders are in consumer photography, lightweight commercial UAS for real estate, the military, law enforcement, border control, homeland security, utility infrastructure surveillance, agriculture, aerial mapping, and package delivery.

Geospatial Industry News

Drone Transponders Market worth $2.5 Billion by 2022

Ed. note: This article originally appeared on the National Snow and Ice Data Center's Highlights website.

NSIDC and NASA data scientists proved the use of 21st-century techniques to revive data from 1960s satellites.

Scientists today who study polar sea ice conditions rely on satellite records reaching back to 1979. But soon, data scientists hope to extend the look back by another decade or more. Researchers at NSIDC and NASA have shown that the oldest Earth observing satellite data can be made to yield new information, adding significantly to the view of Earth's climate history.

When NASA launched the first Nimbus satellite in the 1960s, they also launched an era of Earth observations from space. While the early Nimbus satellites provided meteorological and other observations, methods did not yet exist to detect features such as the margins of the sea ice cover in the Arctic and Antarctic. Even if they had, the limits of computer processing in those days would have made quantitative analysis unfeasible.

These early satellite data still reside in NASA archives on archaic, two-inch tape media. When NSIDC scientist Walt Meier and project manager Dave Gallaher learned that NASA researchers had retrieved 1960s images of Earth from the Lunar Orbiter, they wondered if early NASA satellite data could also yield information about sea ice conditions before 1979. They saw a disappearing window of opportunity to recover these data. Only one tape drive remained in the world that could read the Ampex two-inch media. Plus, the original Nimbus researchers were now in their late 70s and 80s, and contact with them would be critical to answering some of the necessary instrumentation questions.

On September 23, 1966, Nimbus II acquired the temperature data shown in this image of Asia, overlaid on Google Earth. The warm waters of the Persian Gulf are clearly seen in contrast with the cold temperatures of the Himalayas. Blues and greens indicate cooler temperatures, and yellows and reds indicate warmer temperatures.

The Nimbus satellites carried a High Resolution Infrared Radiometer (HRIR), with a resolution of 8 kilometers, a medium-resolution infrared radiometer (MRIR), and an Advanced Vidcon Camera System (AVCS). Although Nimbus collected data for only short periods, Meier suspected that these early Nimbus satellites likely captured the annual Arctic sea ice minimum, occurring each September.

Starting with the methods developed for the Lunar Orbiter Image Recovery Project (LOIRP) at NASA Ames Research Park, a team at NSIDC worked with Dennis Wingo at LOIRP to search NASA archives for the original Nimbus tapes containing raw images and calibrations. Their first goal was to read and reprocess the data at a higher resolution, removing errors resulting from the limits of the original processing.

These tasks proved more challenging than expected, due to truncated data, missing algorithms, and other issues. But the result was a global image of the Arctic from Nimbus II, captured on September 23, 1966, in higher resolution than ever seen before from this type of data. This date falls around the time that Arctic sea ice would have reached its end-of-season minimum extent. The image demonstrates the possibility of reprocessing the entire available time series, supporting new scientific study of past conditions on Earth.

This proof-of-concept research was supported by an Innovative Research Program seed grant from the Cooperative Institute for Research in Environmental Science (CIRES) at the University of Colorado at Boulder, the home of NSIDC.The team now plans to apply for further research funding to expand the study. More work is needed to reprocess 2,600 half-orbit records, develop a de-jitter algorithm, and then complete a painstaking process of image comparison to separate clouds from ice.

Processing of more data could allow Meier and other scientists to determine sea ice extent during the Nimbus I through III campaigns (1964, 1966, and 1969). The team also hopes to extend their methods to later instruments, and characterize both minimum Arctic and maximum Antarctic sea ice extent for 1964 to 1978. If successful, the sea ice climatologies would gain up to fourteen years of data - an increase of 50 percent over their temporal span today.

Techno-Archaeology Rescues Climate Data from Early Satellites: Archived but not Forgotten

For more than a half a century, Earth observation (EO) data has been presenting a synoptic view of our planet. Whether observing a region, a state, a country, or the globe, such a view is key for understanding Earth systems. In recent years, scientists, analysts, and conservationists have had massive volumes of EO data at their fingertips for applied scientific research. Digital slices of daily, weekly, and monthly temperatures or precipitation; global wind or weather patterns; land-cover maps; soil moisture or snow cover information; geological units; and hydrological network or demographics data offer a digital twin of the earth, layer by layer.

Geographic information system (GIS) technology provides a connective thread or spatial context to these layers and a geospatial framework to model and create the what-if scenarios that help us understand the complex challenges facing Earth and its response to biodiversity loss, ecosystem degradation, natural resources management, and climate change. ArcGIS, an open science ecosystem rooted in location intelligence or the "where,” is helping scientists use cutting-edge research tools to conduct analysis, advance science, and provide leaders with reliable information that can drive data-fueled action.

This session explores ArcGIS, interoperability, Python libraries, and open data sharing with authoritative federal sources, for predictive analysis and links to shared notebooks so you can build your scientific models.

Drawing on real-world use cases, you will learn about the following:

An analytical ecosystem for multidisciplinary, extensible, and reproducible research

How to remain agile in problem solving using the ArcGIS ecosystem, which is open and interoperable to easily integrate and work with the tools and languages such as Python, Jupyter Notebooks, and R.

The power of ArcGIS Living Atlas of the World to enrich your scientific work with a broad spectrum of curated and ready-to-analyze data sources

How to create historical trends, see change, and make predictions using time series data

Anyone interested in remote sensing or imagery science and analysis, such as earth and data scientists, GIS users/analysts, geospatial analysts, programmers, project managers, managers, and decision-makers.

Esri applies The Science of Where to connect everyone, everywhere through a common visual language. It combines mapping and analytics to reveal deeper insight into data.

Esri, the global market leader in geographic information system (GIS) software, location intelligence, and mapping, offers the most powerful geospatial cloud available, to help customers unlock the full potential of data to improve operational and business results. Founded in 1969, Esri software is deployed in more than 350,000 organizations including 90 of the Fortune 100 companies, all 50 state governments, more than half of all counties (large and small), and 87 of the Forbes Top 100 Colleges in the US, as well as all 15 Executive Departments of the US Government and dozens of independent agencies. With its pioneering commitment to geospatial information technology, Esri engineers the most advanced solutions for digital transformation, the Internet of Things (IoT), and advanced analytics.

Geospatial Webinars

Exploring Open Scientific Analysis to Understand Earth Systems Processes

You may have noticed that “copyright,” “public domain,” and “1923” have been in the news lately. At midnight on Dec. 31, 2018, certain intellectual property published in 1923 that had been held under copyright underwent a legal transformation and is now part of the public domain. For a while this was an annual occurrence within the copyright lifecycle, since earlier instances of copyright laws had provided protection for authors, artists, and other creators for a fixed number of years (50 years after the author’s death, for example). This cyclical advancing pattern of release was interrupted in 1998 when the Copyright Term Extension Act became law, essentially putting a freeze on the otherwise annual release of things by automatically extending the number of years of protection. Mickey Mouse, Sonny Bono, and the entertainment industry had a lot to do with this, but the impact was necessarily widespread across all materials.

Specifics of copyright protection are complex and detailed, and necessarily so, as the range of original creations worldwide is equally rich. The laws allow individuals and corporations to know that their precious efforts are recognized as such. At the same time, some of our most beloved music, movies, artworks, and the like were directly inspired by previous publications. Imitation is the sincerest form of flattery! Once something is part of the public domain, it can be used, reused, altered, modified, and reworked. It is available to become the raw stuff of inspiration for other creators, which is why some museums are blazing a trail into the open access realm.

Moreover, just because something exists under copyright doesn’t mean one can’t actively use it. For example, the London Underground regularly permits – through authorized licensing – alternative representations of the famous 1931 Harry Beck tube map to be published without legal sanctions. Licensing is what allows still-under-copyright music to stick in our heads in commercials. The standardized language of Creative Commons licenses has been a valuable solution for those wishing to facilitate the sharing of content for creative rather than commercial means, such as the David Rumsey collection of maps.

Meanwhile, think of Jan. 1, 2019, as having been a flush of new public domain content as the release cycle began anew. Books, movies, visual art, and music have received most of the attention, but what about maps? As a reminder, almost all maps published under the auspices of the U.S. Government fall outside of these restrictions anyway, as they are part of the public domain from their beginning. So the phenomenal maps of the Mississippi River that Harold Fisk produced in the early 1940s for the U.S. Corps of Engineers have always been available – and now in digital form – for your use as art inspiration, background images, or screen printing onto t-shirts.

Out-of-copyright (or never under copyright) historical maps exist for many locales. For example, many of the Sanborn Fire Insurance maps, a large and valuable collection for the United States that date back to the year 1866, are slowly and steadily being scanned and becoming available for download from the Library of Congress, at least up to their current year of copyright protection. However, becoming-public-domain at midnight on a certain date is not as similar to the Cinderella-midnight-pumpkin analogy as it may seem. Copyrights could be, and were, extended past these threshold dates when and if authors or publishers registered and then extended the copyright within a particular time frame. If such registration and extension is known with certainty not to have happened, then more recent items may have lost their copyright protections already…except that after 1991, the registration renewal requirement was waived. Really, it’s quite complicated.

There are many layers of politics and legalities surrounding these matters, and few cases are black and white. Prepare to do research, especially when there are no obvious clues to a map’s source and publication date. The U.S. Copyright Office offers suggestions for how to begin this type of investigation (a 12-page PDF document not yet updated with the new 1923 date). And what about new forms of spatial data and novel representations? What does it mean for LiDAR enthusiasts that a 3-dimensional scan may not qualify for protection under copyright? CyArk already shares some of its LiDAR data. Will others?

Are there specific maps published in 1923 that have just entered the public domain? National Geographic was actively producing maps during those years, and their 1923 map of the United States beautifully documents national activities from that time, such as highway expansion. Is this particular map suddenly available to be done with what we wish, by virtue of its alleged publication date? Not so fast. It turns out that this map was, indeed, first published in April 1923, but currently it isn’t known with certainty whether National Geographic previously extended its copyright. Plus, we do not know about licensing arrangements with Art.com, through which National Geographic distributes its historical maps. Can this 1923 map be purchased as a paper reproduction, scanned at a high resolution, and its digital representation then georeferenced to become a basemap within a GIS, with or without requiring attribution or further permission? Inquiring minds want to know, and lawyers will get back to us. Like I said, it’s complicated.

Copyright, Public Domain, and Maps – It’s Complicated

Summary: In this article, Luca Congedo presents a tutorial for the land cover classification of cropland. In particular, he uses Landsat imagery acquired over the State of Kansas, near the city of Ulysses, using the new version 2.3.2 of the Semi-Automatic Classification Plugin for QGIS.

In this post, I am presenting you a tutorial for the land cover classification of cropland. In particular, we are going to classify a Landsat image acquired over the US state of Kansas, near the city of Ulysses, using the new version 2.3.2 of the Semi-Automatic Classification Plugin for QGIS.
 
Before the tutorial, please watch the following video that illustrates the study area and provides very useful information for the interpretation of the image in false colors (footage courtesy of European Space Agency/ESA). Also, a brief description of the area that we are going to classify is available here.As shown in the previous video, the study area is mainly covered by cropland, and we are going to classify a Landsat 8 image acquired in April 2013 (available from the U.S. Geological Survey), using a semi-automatic approach (i.e. the entire image is classified automatically basing on several samples of pixels "ROIs" that are used as reference classes).

Before the classification process, we are going to convert the DN values to reflectance. The reflectance is defined as the ratio between reflected and incident energy on a surface (see here for more information about the conversion to reflectance of Landsat images).

The atmospheric correction of reflectance values is useful during the pre processing phase, because the electromagnetic energy measured by a satellite is affected by the atmospheric effects (e.g. absorption or scattering). Therefore, image conversion to reflectance allows for the comparison and mosaic of different satellite images (e.g. Landsat 5 and Landsat 8), and improves the classification results.

The Semi-automatic Classification Plugin provides a simple correction using the DOS1 method (a brief explanation about image conversion to reflectance and DOS1 atmospheric correction is illustrated in the yellow frame at the end of this post). It is worth mentioning that GRASS GIS has also a tool for  the calculation of the Top Of Atmosphere reflectance (see i.landsat.toar) and other DOS methods.

First, download the image from here. The image is a subset of the entire scene, including the following Landsat bands (each band is a single 16 bit raster):

The following workflow illustrates the main phases of the semi-automatic classification:


1. Conversion of raster bands from DN to reflectance

This phase is part of image pre processing, which enhance the input images by converting the DN (i.e. Digital Numbers) to the physical measure of Top Of Atmosphere reflectance (TOA). Also, we are going to apply a simple atmospheric correction using the DOS1 method (Dark Object Subtraction 1), which is an image-based technique.

As an example, the following images illustrate three charts of different spectral signatures (water, vegetation, and bare soil) calculated with the original image (DN), the TOA reflectance image and the DOS1 corrected reflectance image. As you can see, the DOS1 correction modifies the reflectance values, especially in the blue band. Notice that the band number in the following images is the numerical order of used bands, thus for example: band 1 of the chart is band 2 of Landsat 8 (i.e. blue band).

Open QGIS and start the Semi-Automatic Classification Plugin; in the main interface select the tab Pre processing > Landsat;

Select the directory that contains the Landsat bands (and also the required metafile MTL.txt), and select the output directory where converted bands are saved;

Check the option Apply DOS1 atmospheric correction, and click Perform conversion to convert Landsat bands to reflectance;

At the end of the process, converted bands are loaded in QGIS.

2. Definition of the classification inputs

Now, we create a color composite of the image. In particular, the composite RGB = 543 (that is the equivalent of RGB = 432 for Landsat 7) is useful for the interpretation of cropland in the image (as shown in the previous video by ESA), because of healthy vegetation reflects a large part of the incident light in the near-infrared wavelength.

In order to create the color composite in QGIS, we create a virtual raster. Then, we define the band set that we are going to classify. Finally, we create a training shapefile which stores the ROIs (i.e. Regions Of Interest) that define the land cover classes.

From the menu Raster select Miscellaneous > Build Virtual Raster (catalog); click the button Select... and select the bands 3, 4, and 5; select the output file (for instance rgb.vrt); check Separate (bands will be separated) and click OK;

In the plugin dock ROI creation click the button Band set beside Select an image; the tab Band set will open; click the button Select All, then Add rasters to set (order the band names in ascending order, from top to bottom using ↑ and ↓ arrows);

In order to create the training shapefile (a polygon layer having several attribute fields that will store ROIs), in the dock ROI creation click the button New shapefile, and select where to save the shapefile (for instance ROI.shp).

We need to create several ROI, considering the spectral variability of land cover classes. It is important that ROIs represent homogeneous areas of the image, therefore we are going todraw the ROIs using a region growing process (i.e. a segmentation of the image, grouping similar pixels).

The following are the land cover classes that we are going to identify in the image:

low vegetation (e.g. fields without green vegetation, or shrubland)

built-up (e.g. artificial areas, buildings and asphalt)

As you can see in the color composite, the color of cropland can vary from dark red to light red. We should create several ROIs for each of these colors.

In order to create a ROI, in the dock ROI creation click the button + beside Create a ROI and then click any pixel of the image; zoom in the map and click on a red pixel of a circular field; after a few seconds the ROI polygon will appear over the image (a semitransparent orange polygon);

Under ROI definition type a brief description of the ROI inside the field Information (e.g. crop; notice that descriptions are not used during the classification process, but are useful for distinguishing ROIs); the field ID (i.e. identifier of the class) is used as reference for the land cover classification, therefore it is important that each category has a unique ID value (ROIs sharing the same ID are evaluated as a single ROI); since we need more than one ROI per class, set the ID = 11, so that the first figure represents the class, and second one the ROI number (other crop ROIs will have values from 11 to 19; in the same way we set ID from 21 to 29 for low vegetation, and so on);

In order to save the ROI to the training shapefile click the button Save ROI to shapefile;

In the plugin main interface, select the tab ROI tools > Spectral signature, which displays the plots of selected ROIs, and select the item crop; if the checkox Plot σ is checked, then the plot will display the standard deviation of each ROI.


Repeat the above steps for every class (in order to get the desired ROI, change the values for Minimum ROI size and Range radius); after the collection of several ROIs, it is useful to visualize the ROI spectral signatures in order to avoid the collection of ROIs that are spectrally similar. Following, some examples of ROIs for the land cover classes.

4. Classification of the study area

It is useful to perform classification previews, in order to assess the quality of classification (for example a common problem is soil classified as built-up and vice versa). If the result of the preview is not good, then we need to go back to the phase of ROI creation, delete the faulty ROIs and/or create new ones. 

The classification can be performed through several algorithms; this time we are going to use the Spectral Angle Mapping classification.

In the Classification dock, under Classification preview set Size = 500 (i.e. the side of the classification preview in pixel unit); click the button + and then click on the image; after a few seconds, the classification preview will be loaded (with default colors);For a better interpretation of classes, it is useful to assign a classification color to each class.

Also, we can save a visualization style in QGIS, and set this .qml file as the default style for every classification or preview.

In the panel Layers, left click on the classification preview and select Properties > Style; select the render type Singleband pseudocolor and change the colors and labels of classes, according to the training ROIs; then, click Save style ... to save the .qml file (e.g. classification.qml);

Under Classification style click the button Select qml to select the file classification.qml; thus the next classification or preview will be loaded with this style;When we are satisfied with the result, we can perform the final classification (the main output of a classification is a raster file .tif).

click the button Perform classification and select where to save the output (e.g. classification.tif).

5. Calculation of classification accuracy

It is useful (and necessary) to assess the accuracy of land cover classification, in order to understand the reliability thereof, and to identify map errors.

Please, notice that this classification is only for demonstration purposes, because an accurate land cover classification would require ancillary data and field survey.

However, in order to assess the classification accuracy, we can compare the land cover classification to the ROIs we have created (theoretically, image pixels belonging to a certain ROI should be classified as that ROI's class).

Select the tab Post processing > Accuracy  of the plugin main interface; select the classification.tif beside Select a classification to assess  and select the ROI shapefile beside Select the reference shapefile; then click the button Calculate error matrix and the matrix will be displayed; you can save the error matrix by clicking the button Save error matrix to file; Generally, classification accuracy is considered good if it is > 80%. For this classification, we can see that the overall accuracy of the classification is about 91.4% (the error matrix is reported below). Also, it is useful to consider the error for single classes (i.e. omission and commission).

6. Calculation of classification statistics

The classes of the final classification are more than the main land cover classes we have defined at step 3 (this is because we needed to assign diverse IDs also to ROIs belonging to the same class).

In order to estimate the cropland in the area, we are going to reclassify the classification raster in fewer classes, according to the main land cover classes.

From the Processing toolbox navigate to SAGA > Grid - Tools > Reclassify Grid Values; in the tool window, under Grid selectclassification.tif; under method select [2] simple table;

Under Lookup table click the button ... to open the window Fixed Table; the lookup table has 3 columns: minimum, maximum, and new. Minimum and maximum define the reclassification range for the new value, according to the following table. 

Click "OK" and after a few seconds the reclassified classification will be loaded. Now we can perform the report of the classification, which provides the percentage and the area of land cover classes.

Select the tab Post processing > Classification report  of the plugin main interface; select Reclassified grid beside Select a classificationand click Calculate classification report; after a few seconds the report will be displayed (see the following table).

From these results, we can see that in the study area (at the moment of image acquisition) there are about 738 square kilometers of crop class (class 1, about 10% of the study area) and 6231 square kilometers of low vegetation class (class 2, about 87%). Also, we can notice that about 14 square kilometers are occupied by farms (class 4) and about 18% is built-up (class 3).

Of course, these numbers are the result of a tutorial for demonstration purposes; for a better estimation of class areas (and possibly the identification of the crop type), we need field data which can improve the creation of ROIs and help for the assessment of classification accuracy.

However, the aim of this tutorial is to show how land cover classifications can be performed simply and rapidly using open source programs, which are useful for several activities, such as land cover monitoring or precision farming.

Landsat image conversion to reflectance and DOS1 atmospheric correction

Radiance is the “flux of energy (primarily irradiant or incident energy) per solid angle leaving a unit surface area in a given direction”, “Radiance is what is measured at the sensor and is somewhat dependent on reflectance” (NASA, 2011, p. 47).

The Spectral Radiance at the sensor's aperture (Lλ ) is measured in [watts/(meter squared * ster * μm)] and for Landsat images it is given by (https://landsat.usgs.gov/Landsat8_Using_Product.php):

- ML = Band-specific multiplicative rescaling factor from Landsat metadata (RADIANCE_MULT_BAND_x, where x is the band number)

- AL = Band-specific additive rescaling factor from Landsat metadata (RADIANCE_ADD_BAND_x, where x is the band number)

- Qcal = Quantized and calibrated standard product pixel values (DN)

“For relatively clear Landsat scenes, a reduction in between-scene variability can be achieved through a normalization for solar irradiance by converting spectral radiance, as calculated above, to planetary reflectance or albedo. This combined surface and atmospheric reflectance of the Earth is computed with the following formula” (NASA, 2011, p. 119):

ρp = (π * Lλ * d^2 )/ (ESUNλ *cosθs)

- ρp = Unitless planetary reflectance, which is “the ratio of reflected versus total power energy” (NASA, 2011, p. 47)

- Lλ = Spectral radiance at the sensor's aperture (at-satellite radiance)

- d = Earth-Sun distance in astronomical units (provided with Landsat 8 metafile, and an excel file is available from

  http://landsathandbook.gsfc.nasa.gov/excel_docs/d.xls)

- ESUNλ = Mean solar exo-atmospheric irradiances

- θs = Solar zenith angle in degrees, which is equal to θs = 90° - θe where θe is the Sun elevation

It is worth pointing out that Landsat 8 images are provided with  band-specific rescaling factors that allow for the direct conversion from DN to TOA reflectance. However, the effects of the atmosphere (i.e. a disturbance on the reflectance that varies with the wavelenght) should be considered in order to measure the refletance at the ground. As described by Moran et al. (1992), the land surface reflectance (ρ) is:

ρ = [π * (Lλ - Lp) * d^2]/ [Tv * ( (ESUNλ * cosθs * Tz ) + Edown )]

- Tv is the atmospheric transmittance in the viewing direction

- Tz is the atmospheric transmittance in the illumination direction

- Edown is the downwelling diffuse irradiance

Therefore, we need several atmospheric measurements in order to calculate ρ (physically-based corrections). Alternatively, it is possible to use image-based techniques for the calculation of these parameters, without in-situ measurements during image acquisition.

The Dark Object Subtraction (DOS) is a family of image-based atmospheric corrections.

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