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Is there a tool in QGIS that will extract the row and column numbers of a raster at a set of points? All I have been able to find is the following:

  • Raster Analysis > Sample raster values
  • (Plugin) Point Sampling Tool
  • GRASS > Vector > v.sample

None of these return the row & column number of the point, as far as I have been able to tell.

I also found this question, but it is rather in-depth and I was hoping to find a tool which could do it automatically if possible.

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  • The column number is going to be the X coordinate of the point minus the X coordinate of the left of the raster divided by the cell size, rounded to an integer. You can get the extent and hence the min X of a raster in the expression editor via layer_properties(layername, 'extent') but I can't yet see how to get the cell size or the number of columns...
    – Spacedman
    Jun 22, 2019 at 10:49
  • 1
    Maybe this answer to a similar question can help you: gis.stackexchange.com/questions/261504/…
    – pan
    Jun 22, 2019 at 15:43

1 Answer 1

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One way to do this is with the gdallocationinfo utility:

micha@TP480:GTOPO30$ gdallocationinfo -geoloc gt30e020n40.tif 31 29
Report:
  Location: (1320P,1320L)
  Band 1:
    Value: 15

You enter the X-Y the -geoloc parameter, and X-Y coords at the end, and it returns the Pixel and Line numbers (together with the value at that pixel)

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  • Seems to work but I am kind of surprised that QGIS does not do this automatically, I would think it would be quite useful to have it as a built-in feature, perhaps as a derived output from the identify tool, or as an optional output in the "Sample raster values" tool.
    – wfgeo
    Jun 23, 2019 at 11:36
  • Since QGIS is a GIS application, and everything is done in the georeferenced space, the row and column numbers are not usually important. So I'm not surprised. The lower level tools, such as GDAL, that deal directly with the image do access the row and column numbers.
    – Micha
    Jun 23, 2019 at 12:32

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