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I have a global tif file in epsg:4326 and a shapefile of points distributed around the global. I want to retrieve the sum of the value of pixels around 10km of each point.

One obvious thing to do is to convert tiff to points and intersect in an equal area projection. Unfortunately conversion to points takes ages so i abandoned it.

Then focal statistics with the corresponding buffer and getting value for each point is an option, but what projection do you think is best for this?

I used mollweide and it seems that when I measure the pixels in any area of the world they have the same size.

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  • If you think that convert pixels to points and reproject them must work, reproject the raster is not the same. Starting with a 360x180 pixels raster in EPSG:4326: reproject the points in a Mollweide projection will give you 360 points in a Pole, but just one pixel if you reproject the raster.
    – Gabriel De Luca
    Commented Jan 21, 2020 at 22:07
  • Yes but I assume that this is correct. I am not sure thought how transformation of these 360 to 1 pixel works. Does it sum the values of all pixels to the one? Or it takes the value of the central one and erases the rest...
    – GeoF
    Commented Jan 22, 2020 at 13:23
  • Unfortunately I have a total ignorance of ArcGIS tools, but I suppose the pixel values are not modified when reprojecting the raster, at least this is the case with the GDAL library. The resulting pixel takes the closest pixel value, unless there is an interpolation specified in the process. What kind of data has the original pixels?
    – Gabriel De Luca
    Commented Jan 22, 2020 at 13:43
  • global population data
    – GeoF
    Commented Jan 22, 2020 at 14:15
  • If the population was computed for the projection and cell size of that raster, seems to me better to do not reproject it.
    – Gabriel De Luca
    Commented Jan 22, 2020 at 14:39

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