topic Re: polygon to raster in ArcGIS Spatial Analyst Questions

polygon to raster

Anonymous User — Thu, 07 May 2015 09:19:25 GMT

I have two different polygons A and B, but with the same values of max resistivity. When I run "polygon to raster", arcgis merge A and B polygons. How to prevent the merging of those polygons?

Re: polygon to raster

ThomasSteudel1 — Thu, 07 May 2015 09:55:25 GMT

Hello Ivan,

Does the former A and B area within your raster dataset also have the same ID? If not, you could use the ID to seperate them. If yes try to change the attribute in the Polygon to Raster - Tool within the "value_field" (using the ID field of the shape and not the max resistivity). So your output raster should have for each polygon a different ID without merging. Later you could do some join/spatial statistic operations to get the max resistivity for each "former" polygon.

I can not try to reproduce the steps because we do not have the nescessary licences here.

Re: polygon to raster

JayantaPoddar — Thu, 07 May 2015 11:22:23 GMT

Hi Evan,

FIll the ID field (Add Field, if necessary) of the polygon layer with values 1 and 2 for PolygonA and PolygonB respectively.

Convert the polygon to Raster using the ID field.

Re: polygon to raster

curtvprice — Thu, 07 May 2015 12:47:03 GMT

Here's a more complete explanation, for the good of the thread.

The raster data model is based on a single value per cell for most operations. If you want to preserve attributes on the raster side, these suggestions are right on - specify the ObjectID field as a "Value field" for the Polygon To Raster tool, and then copy the polygon attributes over to the raster attribute table using the Join Field tool.

However, for analysis purposes with raster tools like the Raster Calculator, it really does make sense to convert to raster using the field you will be analyzing. (The Lookup tool may be used in map algebra to access attributes for calculation purposes, but is generally more convenient and efficient to not have to use it.)

Re: polygon to raster

Anonymous User — Thu, 07 May 2015 21:06:54 GMT

Thank you all! solved!