Calculating Percentage of Overlap

Question

Hi,

I have a layer of polygons which indicate different census statistical areas.

I also have another layer which has buffered around a network of bus routes in the city.

I've been playing around with the software but can't quite figure out how to do this. But for each statistical area, I want to calcluate the area within the polygon which is within the buffer layer (i.e. that the buffer layer covers). Can anyone help me with doing this?

Thanks 🙂

EricRice · Answer

It sounds like Tabulate Intersection is up to the task.

Best,
Eric

TOMKONG · Answer

Hi,

I have a layer of polygons which indicate different census statistical areas.

I also have another layer which has buffered around a network of bus routes in the city.

I've been playing around with the software but can't quite figure out how to do this. But for each statistical area, I want to calcluate the area within the polygon which is within the buffer layer (i.e. that the buffer layer covers). Can anyone help me with doing this?

Thanks 🙂

1.add one new field in the network buffered polygon layer attribute table --called Original_Area, then using calculate geometry to get area value for each polygon (you can transfer this data from Area field also)
2.intersect both layers (census & buffered network)
3. From intersected layer, add one new field - called Percentage, then using Field Calculation to get the Area (intersected area value)/Original_Area (from buffered layer) value that you want.

But you need to check the data error and it depends on your source data quality (the network buffering polygons may have overlapping area), and sometimes the result can be changed if you change the buffering distance.

MarkBoucher · Answer

The Union tool might be what you are looking for.
Look under Toolboxes\System Toolboxes\Analysis Tools.tbx\Overlay\Union