zonal statistics result is empty table

[SThompson]

Hello
I am trying to run zonal statistics

zone data = buffered point data (buffer distance = 3km)
raster layer = rainfall = a floating point file with values from 0 to 253.65

the result I get back is an empty table.

when I run the analysis on the point data only, i.e., not the buffered data, I do get results back. So this makes me think the raster layer is fine but it is the buffered point data file that is incorrect.

A previous thread on a similar problem indicated the problem could be related to projections and cooridnate systems, so I had a look and although both files are set to WGS coordinate system, the data frame is in decimal degrees.

Any thoughts?

Thanks!

[curtvprice]

Hello
I am trying to run zonal statistics

zone data = buffered point data (buffer distance = 3km)
raster layer = rainfall = a floating point file with values from 0 to 253.65

the result I get back is an empty table.

when I run the analysis on the point data only, i.e., not the buffered data, I do get results back. So this makes me think the raster layer is fine but it is the buffered point data file that is incorrect.

A previous thread on a similar problem indicated the problem could be related to projections and cooridnate systems, so I had a look and although both files are set to WGS coordinate system, the data frame is in decimal degrees.

Any thoughts?

Thanks!

Zonal statistics is area-weighted (by counting cells), and buffers are dependent on accurate distance measurements. (Square degrees are not a very good measure of area, and having the system convert a buffer distance from meters to degrees on the fly is likely to give you invalid results.)

You'll likely have better luck if your raster and point data are projected (using Project and Project Raster) to a coordinate system, for example, UTM or Albers, before you do the analysis.