Identify boundary of raster grids

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02-10-2021 04:17 PM
MingHan
New Contributor III

Hi Everyone 

   Is there any way to obtain the boundary grids of each colored grids which are shown in the following raster? 

MingHan_0-1613002632190.png

 

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7 Replies
DavidPike
MVP Frequent Contributor

What do you mean by boundary?  

If you want the actual jagged cell boundary, probably use polygon to raster Polygon to Raster (Conversion)—ArcGIS Pro | Documentation and either symbolise by outline, or convert to line.

Otherwise if you mean the rectangular bounds (envelope) - Feature Envelope To Polygon—Help | ArcGIS for Desktop

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DanPatterson
MVP Esteemed Contributor

If it is a raster I think David means

Raster to Polyline (Conversion)—ArcGIS Pro | Documentation

Raster to Polygon (Conversion)—ArcGIS Pro | Documentation

You will end up with a multipart featureclass, so you might want to run

Multipart To Singlepart (Data Management)—ArcGIS Pro | Documentation

to get separate shapes for each polygonal area

You might want to try the polyline option  first but if it isn't satisfactory, you can always convert the polygons to polylines  if you use the raster to polygon option,


... sort of retired...
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DavidPike
MVP Frequent Contributor

Whoops! Yes Indeed 😂

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MingHan
New Contributor III

Hi All

    I tried with this procedure, it works for most of the cases, here is one exception as shown in the following figure: 

    As you can see, when two type of grids is nearby each other, one of their boundaries will be missing. Because the polygon and polyline of the nearby part is overlapped. 

Any suggestions for this problem? 

Thanks 

Ming  

 

MingHan_0-1613057081464.png

 

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DavidPike
MVP Frequent Contributor

I might do a negative buffer of the polygons you have, then erase the original polygon with that buffer.  Then run the polygon to raster tool, ensuring you have an appropriate Cell Size which will not destroy the original boundary when re-rasterized.

Why are you converting this boundary back to a raster? It seems unorthodox.

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MingHan
New Contributor III

Thanks, I will try that, I need to work on the boundary grids showed in the raster map. I do not know how to locate the boundary grids efficiently. 

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DanPatterson
MVP Esteemed Contributor

If it just the boundaries you are concerned about, you dont need to worry about them being different classes.  When represented as a polygon or polyline, their 1 cell thickness will vanish and the features will share an edge.


... sort of retired...
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