Nevermind about the example script, I tested it myself and verified the problem. The fix was simple. We were missing a square root for the denominator of the formula for x and y. Before I submit this patch, can anybody with more knowledge about the hammer projection verify that the equations on the wikipedia page are correct? I would like to verify the transformation before making this change.

Ben Root

hammer.patch (620 Bytes)

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On Wed, Nov 17, 2010 at 8:44 AM, Benjamin Root <ben.root@…1304…> wrote:

On Wed, Nov 17, 2010 at 5:45 AM, Matthias Plum <plum@…669…> wrote:

Hi

I am trying to plot data on the sphere and use the hammer projection.

The data ploting works fine, but the angular grid isn’t shown correctly.

In the attached picture you can see the error(mouse pointer is on the

position 60 E 30 S). Can anyone help me on this subject? Thanks.

Matthias

Matthias,

Looking at the transform equation for Hammer, it looks like there might be a mistake in the calculation. Can you include the script you used to make that figure so I can test the fix?

Thanks,

Ben Root