topic Re: Polygon to raster issue in ArcGIS Pro Questions

Polygon to raster issue

BruceMiller1 — Sun, 29 Nov 2020 15:19:10 GMT

Hi all,

Hoping this new forum format generates some dialog as the previous version seemed to have questions posted rarely responded to.

I have issues with trying to convert a series of polygons that are the result of buffering 200-meter distances from points (cave entrances). These were 0 to 10,000 meters in 200 m increments. I need to convert this to a raster and eventually as an ASCII file for additional spatial modeling.

In either ArcMap or ArcPro the result is a simple single value labeled "10" and not the concentric distances as needed.

I have tried both polygon to raster and feature to raster in the conversion tools.

Seems this was easily completed in the legacy ArcMap 9.X and early 10.X.

Ideas, help appreciated.

Bruce Miller

Re: Polygon to raster issue

DavidPike — Sun, 29 Nov 2020 15:31:59 GMT

Were the buffers generated with the multiple ring buffer tool?

One guess would be that you have overlapping disks rather than rings as an output from the multi ring buffer. A polygon to raster would only take the max value from the overlap.

Re: Polygon to raster issue

SteveLynch — Sun, 29 Nov 2020 15:42:43 GMT

What cell size are you using and how many columns and rows does the output raster have?

Re: Polygon to raster issue

DanPatterson — Sun, 29 Nov 2020 15:49:21 GMT

To follow up on David and Steve

Multiple Ring Buffer (Analysis)—ArcGIS Pro | Documentation

see the details about whether to dissolve or keep overlaps

and your cell size really needs to be specified otherwise you get 1/250 of the width/height of the extent of the input. Cell size and all the other inputs really need to be specified

Re: Polygon to raster issue

BruceMiller1 — Thu, 03 Dec 2020 13:31:32 GMT

Hi all,

Been traveling to escape northern winter but settled now and back at work. Multi ring buffers were created and not dissolved so I can retain the distances from each point. I did specify cell size. Yes there are overlapping rings for some adjacent nearby cave features that are closer than the 5,000 meter distances.

If I can convert this to a simple ASCII grid that will work for my needs but seems to not be working in either ArcPro or ArcMap 10.8.

Re: Polygon to raster issue

BruceMiller1 — Thu, 03 Dec 2020 13:55:37 GMT

Also, I have an older ASCII grid file for cave distances created with ArcMap 9x eons ago. Since then I have updated cave locations including about a dozen more that were missing or not well georeferenced. So more precise locations. If I can update this file with header data:

ncols 213
nrows 306
xllcorner 254158
yllcorner 1748000
cellsize 1000
NODATA_value -9999

Re: Polygon to raster issue

DavidPike — Thu, 03 Dec 2020 14:05:50 GMT

I think you could just run a euclidean distance with a 'maximum distance' set. then reclassify.

Re: Polygon to raster issue

BruceMiller1 — Thu, 03 Dec 2020 15:19:06 GMT

Hi Mike,

Not sure about only a max distance as what is needed for ecological niche modeling is the proximity distances from cave entrances. I may need to rerun all with 200 m increments. The previous ASCII version used proved that proximity distance was very important.

Re: Polygon to raster issue

DavidPike — Thu, 03 Dec 2020 15:27:57 GMT

the max distance is the max from each point, i'm not sure what you mean.

the euclidean distance is a raster where each value is the distance to the closest input feature. i quickly ran the tool to demonstrate. this can easily be converted(reclassified) to your desired bands.