Learning New Things with ArcGIS

Creating Multiple Buffers

I knew how to create one buffer at a time, but I found out that this tool enables me to create a buffer for multiple points at once, but only for one layer at a time. And with one layer, I can create as many buffers as I need to.

In the map above, I used Delaware County Data from Delaware County, Ohio.

In the map, you can see several little points throughout the county, especially concentrated in the north. These are locally historic buildings and the buffers I created are not based on other data. I made up a situation that within each buffer of each point, that would be the area of growth. For example, take any point on the map. At that point, there are 4 different shades of blue. The darkest shade of blue shows the most likely area of early buildings from around the same time as the point in question. Then, the lighter shade of blue which extends further out from the point are possibly developed later than the point, and so on and so forth.

Selecting by Location

Ever since I have been using ArcGIS, I have always been selecting by attribute. And now I figured out how to select by location. This enables me to select features/layers that interact with another layer.

In the map above, you may not be able to tell what I did, but I only used two layers for this map. The first layer is of school districts within the county, and the second layer is of townships in the county. Then, selecting by location, I asked the software to select all of the townships that share a border with a school district line. However, every township border shared at least one side with a school district. I thought that there would at least be one township entirely in the middle or surrounded by one school district, but from the map above, that isn’t true.