Is there a way to highlight a section of a river that falls withing an overlaying kernel density plot?

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04-09-2019 05:49 AM
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by Anonymous User
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So I have two .shp feature classes (Rivers and River use) as well as a Raster layer, which is a kernel density of River use > 0. 

Is there a way to change the color of the river polygons where overlaying kernel density is present (ie. sections of river where there is river use)?

Example of kernel density overlaying rivers

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5 Replies
Suzanne-Boden
Esri Regular Contributor

Hi Christopher, an easy, quick way to do this if your "river polygons" are the nine areas shown in the screenshot above is to manually select the eight polygons that contain a kernel density, then save the selection as its own layer (right-click the river polygon layer > Selection > Create layer from selected features). Change the symbology of the new layer, which will draw on top of the original layer. 

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by Anonymous User
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Thanks Suzanne, however, I may have poorly explained what I am actually trying to do which is change the color of the blue rivers where the density lies directly over it. My thought is that I could then hide the density plot and be left with red sections of river where the density plot once overlayed. Does that make sense?

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Robert_LeClair
Esri Notable Contributor

One way that comes to mind:

  • Convert your Rivers polygon to a raster using the Feature to Raster GP tool.  The FIELD parameter will assign the cell value to the raster.  This could be a "dummy" field in the feature class calc'ed to one for example.
  • Then run the Mosaic to New Raster GP tool.  The first input could be your DENSITY raster.  The second input is your Lakes raster.  For the MOSAIC OPERATOR parameter, this could be set to FIRST.  So wherever the 2 rasters overlap, the value from the first raster, DENSITY, is used for the output cells in the new output raster dataset.  If there is no overlap, then cell values are derived from the DENSITY and LAKES raster respectively.
  • Then add your new raster dataset to a map and symbolize accordingly.  The dummy cell values for the lake are blue and other density cell values get their red color ramp colors.


Should work!

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by Anonymous User
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I have found a way to do this that is exactly what I was hoping for. 

Step 1.) Use Reclassify tool on the Kernal Density Raster layer

Step 2.) Use the Raster to Polygon tool

Step 3.) Select by attributes on new layer

Step 4.) Export  selected data to new layer.

Step 5.) Use the intersect tool

Suzanne-Boden
Esri Regular Contributor

Awesome, Christopher! Your map clearly shows river section use. Thanks for sharing the solution. 

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