How Big Is An Acre?

How big is an acre? When I was in college in the late '60s that was a valid test question. I was a forestry major and we were expected to know this information. (For the purpose of this editorial, please substitute hectare if you are outside the U. S.) My class was composed of about 35 students, out of an undergraduate population of 7,000. Add the students from all years and other academic majors who would need to know this information and perhaps we had 500 students at this one school able to answer this question. That was about 7% of the student population. I suspect that a liberal arts school might have an even smaller number of people who graduate knowing this common area measure.

If you are reading this editorial, you are probably a GIS user and you might find my question insulting. That is not the intent. Rather, have you ever asked the audience in a public meeting, "How big is an acre?" How about asking your co-workers, supervisors, and end users of your data the same question? If you have never done this before, you will probably be shocked at the answer. But before you become critical, consider the small population of students who actually learn this in school. As GIS professionals, we can certainly hold our heads high and require everyone to learn this area measure, but at what cost? Built within thousands of GIS installations are critical information layers that we summarize, analyze and model every day to produce important information. This information is then given to decision makers to make important choices. I find it frightening to think about the disparity between the information content provided and the amount actually assimilated by the end users. We, the GIS community, simply need to do a better job in the way we present information, and that means more than just a better map, graph or tabular presentation.

Just a little over a year ago, Google unveiled Google Earth, and while it was not the first whole earth viewer, the company’s market reach, combined with free distribution, made it possibly the most wide reaching spatial information application ever created. Arguable as that last statement might be, the communication value of Google Earth cannot be overstated. What makes it so helpful? 3D, something everyone can assimilate. A very simple adjustment to the viewing angle transitions the observer from a 2D presentation to a 3D perspective. Add 3D content (buildings and landscape features) and suddenly the numerical size of an acre becomes less important to the understanding of the data. Do we still need to quantify our analysis results? Certainly, but we also need to know that our information can be consumed.

From my perspective, 3D seems to hold the answer to this comprehension issue. I will be so bold as to suggest that GIS managers not looking at a 3D transition should make sure their resumes are current. Similarly, GIS companies not embracing 3D might find their market share dwindling rapidly.

This is intended to be the first in a series of editorials that I hope will stimulate your thoughts and comments on 3D GIS and the assimilation of data by our consuming audience. I am sure that everyone realizes that "How big is an acre?" could easily be replaced with a number of other questions that would point to a similar understanding dilemma (e.g., What does 1:24,000 mean?). Oh, and by the way, an acre is 43,560 square feet.