Two methods of selection in ArcMap that I thought would be the same are in fact not equal. I created a 3 mile buffer around a single line feature (approx 6mi in length). I'm working with parcels, as points, that should be within 3 miles of the line feature.
Method 1) Create buffer of 3 miles based on line. Select by attribute > target = parcels > source = buffer > selection method = intersect. This yielded 77374 parcels.
Method 2) Select by attribute > target = parcels > source = line > selection method = within a distance: 3 miles. This yielded 77399 parcels.
The missing 25 parcels are found close to the boundary of the buffer along curves.
So, how does ArcMap build a buffer around a line?
Buffers around a point result in a curve with a single vertex. The picture shows the vertices of the buffer. The parts of the buffer that are made from the endpoints are a series of connected points about 1k feet apart instead of a curve. Is there a way add curves or decrease spacing of vertices as environments in the tool?
I ended up buffering all the vertices in the line feature, dissolving them, union with original buffer, dissolve those. Then selecting by intersection yields the correct count and has a difference in area of ~600k sqft.