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I am trying to figure out how to combine two adjacent rasters into one raster using ArcMap 9.3.1. The problem I am having is that there appears to be a gap in the data. I would like to be able to combine the rasters and/or contour data created from the raster datasets into one so that I can get rid of the gap in information. I am eventually going to do a watershed analysis, so I am seeing the gap in information as a problem.

I'd post a screenshot but I don't have enough reputation points yet.

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If you post a screenshot to I'm happy to upload it. – djq Feb 17 '11 at 17:33
up vote 5 down vote accepted

You need to create a raster that has spatial extents that contain both of your previous rasters (see Create Raster Dataset). I suggest setting the value for this new raster to be 0.

Then, you can add the existing rasters to the new blank raster. To fill in the gap, you can use Spatial Analyst, choosing the option Neighborhood Statistics to interpolate or smooth the gap. Depending on how big it is you may need to adjust the radius you are choosing to smooth.

You may also want to run the smooth part, and then recombine your rasters so that you do not loose resolution on your entire dataset.

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Thanks, that got me headed in the right direction. I used the "Create Raster Dataset" tool found under Data Management Tools in the Toolbox and set it to 0 as you suggested. Then I used the "Mosaic" tool to add my Existing Rasters to the newly created one with the "Blend" function. This both added the Raster Data and merged the two together. Results look good. I may have been able to skip a step by just using the "Mosaic to New Raster" tool. Thanks Again! – WRector Feb 17 '11 at 20:19

There is some generic information on patching the gaps at which can be translated into any gis environment

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