I have a high-resolution World View 2 satellite image with a cell size of 0.5 m. However the image is in a WGS84 coordinate system, so to get meter distance values instead of degrees I have converted it to a WGS84 UTM projection.

The raster in UTM projection has a cell size of 0.35.

How can I convert the image into a UTM projection and maintain the 0.5 m cell size?

I am using ArcGIS Pro and converted the coordinate system from WGS84 to UTM using "Project Raster" tool.

  • 2
    Define Raster Projection is almost always the wrong tool for the job; instead you want Project Raster. – Vince Jul 27 at 11:14
  • Apologies, the tool was Project Raster. From what I remember, it is not possible to use Define Projection on raster files. – EdyK Jul 27 at 12:24

First, as @Vince said in the comments you want to be using Project Raster rather than Define Projection. Project Raster lets you switch between known projections, where as Define Projection is when your data does not have a defined projection.

Second, take a look at the Environment Settings, specifically Cell Size. The setting allows you to force the output pixels to be a certain size, so you could set this to be 0.5 meters. Note, that any kind of reprojection or warping of rasters is going to adjust the pixels slightly, in terms of size or shape (which is why you initially got 0.35m pixels). When you force them to remain 0.5m resampling of your data is going to occur. Depending on how you are using the data this may or may not be an issue.

In this GIS SE post about raster values changing after reprojecting take a look at @SonOfABeach's answer for some additional details on how reprojecting effects pixel values.

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  • 1) Apologies, the tool I used was indeed Project Raster. 2A) Does this mean it is normal for raster reprojections to result in a different cell size / pixel resolution? 2B) You mentioned that resampling may be an issue if I force cell sizes to remain. Does this mean that resampling does not occur when you do not force pixels to remain at 0.5m (i.e. run project raster using the default environment settings)? – EdyK Jul 27 at 12:25
  • @EdyK 2A - yes, that is correct. 2B - some warping will still occur. See the link I'm about to add to my answer for more details. – ycartwhelen Jul 27 at 12:48

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