The one 'constant' about geography is that it is always changing. Some geography changes faster than others. In general, natural features change much more slowly than man-made (cultural) features. Rivers, lakes and mountains may stay in the same place for a long time, but roads, road names and addresses change regularly. As a whole, the transportation network is in a constant state of flux. New streets are being added all the time, old ones are closed and the characteristics of existing streets change frequently. What is an optimal route today may well be sub-optimal tomorrow. Similarly, new homes and businesses are being built and old ones torn down and so what is geocodeable today may not be tomorrow.
Even small amounts of change in the base geographic data can have a
significant impact on the effectiveness and reliability of an application
built upon that data. Many 'free' databases are updated infrequently,
if at all. The accuracy, currency and completeness of the data itself
are often questionable or unknown. Unknown errors can be as problematic
as missing data. If you don't know where the errors are, you don't
know when you can depend upon the data.
Where can an organization with an important application obtain good, reliable, maintained geographic base data?
Some government departments in the United States and Canada have indicated a desire to create and maintain base geographic data, including attributed street networks. Are they up to the task? This is questionable, since the creation, and particularly the maintenance of geographic base data (especially street and address data) is an all-consuming task. It never stops. Because the sources of the update information are local in nature, the maintenance of a national file requires the coordination of literally thousands or tens of thousands of different government departments across the nation. It is difficult enough for two government departments to work together. How can thousands be expected to do so, and on an ongoing, regular basis?
Another concern with a government-based solution is one of mandate. The creation and maintenance of a commercial grade street and address database is not really the mandate of any government department. As such, the enthusiasm for the project and the quality of the product will be subject to changing government priorities. The census authorities in both the US and Canada have produced street files, but neither has created a file that is sufficiently current and regularly maintained to support commercial applications.
The logical alternative to a government-based solution is to source
the data from a private sector provider. There are a number of high
quality geographic base data companies in the market. The advantages
with a private sector provider are several. There is no need for
coordination between multiple stakeholders. The private sector data
provider has the autonomy and authority to make unilateral decisions about
how, where, and when to collect data and how to present it. They
can also create, and strictly enforce, a unified data standard across the
entire geography, and employ a wide variety of methods and sources to ensure
The private sector data provider is also focused on meeting the requirements of the market place through the simple but demanding expedient of the bottom line. The private sector provider must produce and maintain a good product that meets specific market needs or it will not be saleable. Government organizations do not share the same accountability. The needs of the market place change rapidly. The private sector is geared to react swiftly to these changing needs. Government is simply not capable of rapid change.
With apologies to Milton Friedman, 'there's no such thing as a free lunch'. If you use free data, expect to live with the consequences. If you have a critical application, select your base data carefully, from a source you can rely upon to deliver up-to-date, complete, accurate information on an ongoing basis. Your base data costs will likely be a small portion of your total application costs. Don't jeopardize the whole to save money on one component.And don't expect the government to solve all your problems.