POST
|
Xander Bakker Please specify "Maximum" as Statistic Type parameter, not "Sum". I want the output to be an Integer raster. "Sum" statistic forced the output to be a 32-bit floating point raster. I suspect that the output Integer raster is being cast as a Signed 8-bit grid (values of -127 -> +128) when it should be cast as an Unsigned 8-bit grid (values of 0 -> +255).
... View more
12-12-2017
01:25 PM
|
0
|
3
|
1499
|
POST
|
Xander Bakker Thanks for testing out Zonal Statistics as Table. I have always had the "correct" answers from that tool. Could you try Zonal Statistics tool (which outputs a raster with the value of the statistic of choice for each zone) with the StraighLine feature class against ras127 and ras128? I'm curious to see if you can reproduce my results.
... View more
12-12-2017
12:00 PM
|
0
|
6
|
1499
|
POST
|
@kate_ballard @xander_bakker I've seen the same behavior in my integer raster datasets containing values in the range 128 (2^7) through 255 (2^8 - 1), inclusive, using ArcGIS 10.5.1.7333. You can easily reproduce this error by creating a feature class with a simple two vertex line, a constant-value rasterof the same extent with VALUE == 127, and another constant-value raster with VALUE == 128. Run the Zonal Statistics tool to determine the Maximum value for the line using each raster as input. The result for the VALUE == 127 raster is 127. The result for the VALUE == 128 raster is -128. I first became aware when I ran the Zonal Statistics tool against a raster with values 0->139. The output raster had zonal maxima of -117 (256-139). I thought something was fishy. Workarounds might be to add 256 to all negative results, or to convert integer rasters with any values in the range of 128->255, inclusive, to floating point rasters before running Zonal Statistics.
... View more
12-12-2017
09:13 AM
|
1
|
9
|
1498
|
Title | Kudos | Posted |
---|---|---|
1 | 12-12-2017 09:13 AM |
Online Status |
Offline
|
Date Last Visited |
11-11-2020
02:24 AM
|