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I have a GeoTIFF (USGS Land Use / Land Cover) which works great with AERSURFACE. If I use gdalinfo to get the coordinate system, it comes back as:

PROJCRS["unknown", BASEGEOGCRS["NAD83", DATUM["North_American_Datum_1983", ELLIPSOID["GRS 1980",6378137,298.257222101004, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4269]], CONVERSION["Albers Equal Area", METHOD["Albers Equal Area", ID["EPSG",9822]], PARAMETER["Latitude of false origin",23, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8821]], PARAMETER["Longitude of false origin",-96, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8822]], PARAMETER["Latitude of 1st standard parallel",29.5, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8823]], PARAMETER["Latitude of 2nd standard parallel",45.5, ANGLEUNIT["degree",0.0174532925199433], ID["EPSG",8824]], PARAMETER["Easting at false origin",0, LENGTHUNIT["metre",1], ID["EPSG",8826]], PARAMETER["Northing at false origin",0, LENGTHUNIT["metre",1], ID["EPSG",8827]]], CS[Cartesian,2], AXIS["easting",east, ORDER[1], LENGTHUNIT["metre",1, ID["EPSG",9001]]], AXIS["northing",north, ORDER[2], LENGTHUNIT["metre",1, ID["EPSG",9001]]]]

9822 isn't a valid EPSG code (??any more??) but I've seen a custom definition similar to this:

PROJECTION "proj=aea" "lat_1=29.83333333333334" "lat_2=45.83333333333334" "lat_0=37.5" "lon_0=-96" "x_0=0" "y_0=0" "ellps=WGS84" "datum=WGS84" "units=m" "no_defs" END

I'm trying to set up a MapServer (for Windows) using the custom definition so that I can serve up sections of the large (16GB) image. When I try to make a GetMap request, how do I specify the "default" projection for my map? The SRS/CRS parameter is required and must be specified with an EPSG name. But, in my case, I'm just trying to get whatever is defined for the map.

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    One way is to add a custom projection with a fake EPSG code. A well known example from the past is EPSG:900913. In earlier days it was enough to add a new line into a text file named epsg that ships with MapServer but with the new versions of MapServer and Proj library it may not be as easy any more. But MapServer can re-project on-the-fly so it should be fine to use your image as it is and use any SRS/CRS in GetMap (you must configure what codes you support in the mapfile). WMS does not have a concept of default SRS/CRS but user must always define the desired output in GetMap request.
    – user30184
    Commented Sep 7, 2021 at 7:37
  • Could you add the LAYER part of your mapfile and a link to some test data if possible?
    – user30184
    Commented Sep 7, 2021 at 8:11
  • In that place code 9822 means the Albers Equal Area method METHOD["Albers Equal Area", ID["EPSG",9822]] just like 9001 in another place means metre ["metre",1, ID["EPSG",9001]. This definition does not contain EPSG code for the complete projected coordinate system.
    – user30184
    Commented Sep 7, 2021 at 8:19
  • see gis.stackexchange.com/questions/301733/… for similar issue
    – nmtoken
    Commented Nov 8, 2021 at 13:26
  • epsg:9822 is a valid EPSG CRS code, it isn't however anything to do with North American datum or Albers Equal Area ~ epsg.org/crs/wkt/id/9822
    – nmtoken
    Commented Nov 8, 2021 at 13:35

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