Transformation from GRS_1980 to OGSB_1936

[MS10]

Hi, I'm attempting a transformation between these two coordinate systems. I've tried by adding the GRS_1980 raster then selecting Transformations > Using, however the only option is <custom> New Geographic Transformation. I used this method then tried to clip the GRS_1980 raster to the OGSB_1936 however I dont think it has worked correctly as the GRS raster doesnt align and overlay properly with the OGSB raster. Anyone have any advice, some details on the datasets below.

GRS_1980:

Spatial coverage: Europe

Pixel size: 500m

OGSB_1936:

Digital Elevation Model of area in southern England

Pixel size:50

[MS10]

OSGB data is here:

I've already succesfully used the OSGB to ETRS_1989 transformation on this data:

[MS10]

Note: I have been clipping (Data Management > Clip) the GRS_1980 data to the OSGB data prior to attempting any transfomations.

[NeilAyres]

And what are the details of your clip polygon?

See that error there - about empty geometry.

I think that the underlying raster and your clip geometry are not in the same coordinate system.

[MS10]

Clip raster is here:

[NeilAyres]

Then I still think you have messed up the coordinate system of the Lambert data.

I think it should look like this :

Note, this is the same parameters as your original, but the GCS is specified as WGS84

[MelitaKennedy]

I agree with Neil. On your step when you change the coordinate system, rather than selecting the geographic coordinate system folder, right click the name of the current coordinate system, GRS_1980_IUGG_1980_Lambert_Azimuthal_Equal_Area, and select modify. That will open the dialog that I showed earlier. On that dialog, click the geographic coordinate system button on the lower right side. That will leave the Lambert azimuthal projection and parameters alone.