Aerial View Maps

Anyone with knowledge about USGS maps, please help?

I have to make this topo map of my neighbor hood, and the school is purple. What I was taught, purple coloring meant limestone of some type (I don't have the book right next to me), why is the school the same color purple? From what I know, the school is not made of limestone. buildings are represented, and i went on the web site, and there is some symbol for school, but my school is just purple, not the symbol and yes, im positive it's my school.

Public Comments

1. topographic maps describe the ground composition and do not count in buildings so if you try digging at your school the bedrock will be limestone
2. First of all, the first answer is wrong. USGS topo maps DO NOT show ground composition (geology) and they DO show buildings. USGS has other maps that show geology but not their 7.5" topo maps. As for buildings, I'm looking at a map right now that shows them. Now, without seeing it, I'm betting that the map was revised and the building was an addition to the newly revised map. Buildings on USGS topo maps are typically colored black but when a map is updated, or revised, new buildings are shown with a purple color. The date of revision and some sort of legend should be on the bottom of the map. USGS topo maps do not show geologic formations so I doubt it's referring to limestone. Look at the bottom of the map for information on the date of publication and revision. If I'm right, it will show the purple color and anything on the map of that color was added in the revision.