In the Oct. 12th 2018 NY Times an article titled “A MAP OF EVERY BUILDING IN AMERICA” was published. I thought, WOW! that’s pretty sweeping, I wonder if it is true. Here’s a tinyurl link to the article: http://tinyurl.com/ycrl23ce
In the article they describe what they did and provide links to the source data so I downloaded the data and winnowed it down to Windham. That’s usually the first thing to do with Big Data – make it as small as possible. Of course it is not a map of every building, but what they did and how they did it is a good piece of work and one can learn a bit from the article.
Loading the data into a gis application ( plug for QGIS.org ) and comparing their results to Vermont’s 911 data we can see that they miss quite a few Windham buildings.
This first map is of their data and southern Vermont.
And the last image shows both data sets – the Times data in black squares and VT data larger transparent circles.
So one can see that a lot was missed by the Times approach. To be more exact, the Times data shows 296 buildings and the VT 911 data shows 472.