sinu transformations with spherical datum incorrect

[gbrauen]

The sinu class of transformations support both elliptical and spherical datums.

Both forward and inverse transformations with spherical datums are incorrect.

I'll attach a diff to add a test using EPSG:53008 to test/testdata.js which currently fails. Correct values were determined using proj4.

[gbrauen]

It seems like there may be two issues here:

1) proj4js seems to invoke datum shifts for spherical datums unless the proj description contains "+datum=none". This seems to be different from the proj4 command line behaviour. If I add "+datum=none" to the EPSG:53008 code in the patch posted above, then the result from the forward projection matches the results from proj4.

2) Inverse projections are not working. Even with the "+datum=none" change mentioned, the inverse projection result does not match the proj4 command line.

[gbrauen]

I am attaching a patch to this that fixes the handling of sinu for spherical datums, as long as the "+datum=none" pair is added to the proj description. I'm unsure what to do about needing to add that parameter pair.

proj4js_r2314_sinu_spherical_datum_FIX.diff

The update patch is cumulative with the first one I included to show the original problem.

Also, it changes one line in test/index.html to use proj4js.js rather than proj4js-combined.js so I didn't have to rebuild the combined script. I have to change all of the line endings in the build script and then the relevant diffs for this problem are really hard to find among all of the script and proj4js-combined.js cosmetic changes.

[madair]

opened as github issue ​https://github.com/proj4js/proj4js/issues/53

will be fixed there.