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I am having some trouble aligning a raster (elevation) to a fishnet I created. The cell sizes for both the raster and the fishnet are 30x30 meters. I have tried using the clip and extract by mask tools to clip the raster to the fishnet; I made sure that the extent was set to match that of the fishnet. Any thoughts?

For those asking for a screenshot for added clarity. The first image is an example of another raster that I was able to successfully align to the fishnet. In this case, I converted it from a polygon to a raster and made sure the output coordinates and processing extent were the same as my fishnet.

The second image is my elevation raster that will not align to the fishnet.

enter image description here

enter image description here

  • Can you describe a bit more on how the two are not aligning? Raster is bigger than fishnet, fishnet is bigger, etc.? – mkennedy Jan 29 '16 at 22:29
  • A screenshot of the problem would be helpful. – Aaron Jan 29 '16 at 22:35
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If the raster has the right cell values but is just off in the alignment I would ...

  1. convert the raster to a point file
  2. go into an edit session and move the points so they line up in the center of the fishnet
  3. do a spatial join to assign the values from the point layer to the (polygon) fishnet
  4. convert the fishnet to a raster.

Another thing to consider if the fishnet and DEM are close but not exactly the same (like in your screenshots) is possibly using a "Snap Raster" whenever you are doing a raster operation. You could create a raster from the fishnet and then use that as the snap raster. You may want to work the other way around though and make the fishnet conform to the DEM. You could try using the DEM as the "Template Extent" dataset when creating the fishnet.

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Your goal/question is a bit vague but as long as the mis-alignment is on the order of cm and not meters use @jbchurchill's answer. His method might be easier for you. However it will incorporate a systematic shift in your final result. Given the resolution of the DEM (30 meters) a shift of centimeters or (perhaps) even a few meters may not be important to you. Your call.

Otherwise to achieve what you want with the general method described in your question, both the raster and the fishnet need to be in the same Projected Coordinate System. And remember, even if the extents are set the same between the raster and vector data, Raster Coordinates may call to the center of the cell. Vector Coordinates are to the vertices so you'll likely need an offset to make them line up.

  • So it may be as simple projecting my input raster (in this case elevation) into the same projected coordinate system as the fishnet and THEN trying to align them? Currently I believe they are, in fact, different. – Eric M Feb 1 '16 at 14:34
  • @EricM -- If they are different then are likely (almost certain) to have a different origin and so be offset from one another. -- Based on your 2nd image I would say this seems to be the problem. -- Note: It is common Best Practice to always be working in the same Projection across data sets when Editing or doing Analysis. – user23715 Feb 2 '16 at 20:18
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I had the same problem after creating a raster from a fishnet polygon - I could not get the raster to align with the fishnet since I didn't have a snap raster to use and AFAIK there is no way of snapping the raster to a polygon layer (i.e. the fishnet).

A simple solution is the Shift tool in the Projections and Transformations/Raster toolkit. Zoom into almost a single cell scale and use the measure tool to determine the x and y offset between the fishnet and the raster, these are your inputs to the Shift tool.

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