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I'm looking into the EMAG2 dataset (http://www.geomag.org/models/emag2.html) which claims to be a 2 arc minute resolution. I want to create square pixel tiles where pixels will be of an exact distance like 100m or 100Km. But how can this be done if the grid cells may be of different areas on difference places in the world?

To reiterate, if a dataset is 2 arc minute resolution, does that mean the grid cells change aspect ratio and area size at different coordinates in the world?

I'd prefer to use the GDAL/OGR toolset.


Edited according to clarification: How do you convert an arc-based (e.g. 2 arc-minute) resolution grid dataset to a square aspect-ratio "pixel like" (e.g. 100Km by 100Km pixels) resolution raster image dataset assuming that arc-based resolution grids have grid cells that have different area sizes at different coordinates? (this assumption may not be true, please tell me if so.)

  • The algorithms for raster reprojection are well known and easily researched. The resampling method is usually a parameter to the command. This Question seems to be more statement of fact than question. Do you have specific issue with the reliability of a specific set of parametets to convert a specific image? If so, please edit the question. – Vince Oct 18 '16 at 10:37
  • The question is firstly: "To reiterate, if a dataset is 2 arc minute resolution, does that mean the grid cells change aspect ratio and area size at different coordinates in the world?" and secondly: "But how can this be done if the grid cells may be of different areas on difference places in the world?". As for the specific image, it's the EMAG2 dataset, of which there are many formats available. But I'm just confused in general regarding arc-based resolution vs pixel based resolution. – CMCDragonkai Oct 18 '16 at 11:33
  • As per the Tour there should be only one question asked per question. – PolyGeo Oct 18 '16 at 11:49
  • Please edit the question in response to requests for clarification. Even if there weren't two questions, this is still too broad, because it would require a textbook chapter to explain how image projection works. – Vince Oct 18 '16 at 13:23
  • While I don't fully know all of image projections, I understand the concept. All I'm asking is about how this applies to arc based resolution datasets, since this implies that grid cells have different areas (due to changing distance aspect ratios) for every cell. – CMCDragonkai Oct 18 '16 at 13:50

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