[Proj] GeoTiff <-> Proj.4

support.mn at elisanet.fi support.mn at elisanet.fi
Wed Oct 1 10:08:12 EDT 2008


There is no general rule how to map GeoTiff GeoKeys to proj.4
parameters (or is there?) Every projection has it's own mapping?

Can I write "lat_ts" instead of "lat_0" ??

Is there "lon_ts"?

Here I have those keys I have found some mapping,
but how about the others. Must be different for each


ProjLinearUnitSizeGeoKey	3077 in meters                 

ProjStdParallelGeoKey		3078 in GeogAngularUnit -> lat_1
ProjStdParallel2GeoKey	3079 in GeogAngularUnit -> lat_2
ProjOriginLongGeoKey		3080 in GeogAngularUnit  -> lon_0
ProjOriginLatGeoKey		3081 in GeogAngularUnit  -> lat_0
ProjFalseOriginLongGeoKey	3084 in GeogAngularUnit 
ProjFalseOriginLatGeoKey	3085 in GeogAngularUnit 
ProjCenterLongGeoKey	3088 in GeogAngularUnit 
ProjCenterLatGeoKey		3089 in GeogAngularUnit 

ProjFalseEastingGeoKey	3082 in ProjLinearUnits -> x_0
ProjFalseNorthingGeoKey	3083 in ProjLinearUnits -> y_0
ProjFalseOriginEastingGeoKey	3086 in ProjLinearUnits 
ProjFalseOriginNorthingGeoKey	3087 in ProjLinearUnits 
ProjCenterEastingGeoKey	3090 in ProjLinearUnits 
ProjCenterNorthingGeoKey	3091 in ProjLinearUnits 

ProjScaleAtOriginGeoKey	3092 in ratio   -> k_0
ProjScaleAtCenterGeoKey	3093 in ratio   

ProjAzimuthAngleGeoKey	3094 in GeogAzimuthUnit -> alpha
ProjStraightVertPoleLongGeoKey	3095 in GeogAngularUnit 
ProjRectifiedGridAngleGeoKey	3096 in GeogAngularUnit 


Regards: Janne.

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