[ncl-talk] questions about WEB Mercator map projection

[Rick Brownrigg]

Hi,

No, as you note, NCL does not support WEB Mercator. I am not familiar
enough with the projection codes to advise how/where to make modifications.
However, you might find the following document useful -- it details the
differences between Mercator and WEB Mercator, showing the relative error
between the two.

Good luck!

http://earth-info.nga.mil/GandG/wgs84/web_mercator/%28U%29%20NGA_SIG_0011_1.0.0_WEBMERC.pdf



On Tue, Apr 10, 2018 at 11:59 PM, 康贤彪 <xianbiaokang at 163.com> wrote:

> Hi, All
>     Whether the NCL support WEB mercator map projection?  if not, could
> someone be kindly give me some advice how to make some modifications to the
> NCL source code so that it supports the WEB mercator projection?
>    As we have known, the NCL indeed support mercater map projection, in
> which the earth radius is decreasing from equator to higher latitudes.
> However, the google map uses the WEB mercator, where the earth radius is
> kept to a constant in anywhere of the earth.  Now I need to  plot a shaded
> coutour figures and then overlay it onto the google map, So the coutours I
> have to draw should use the WEB mercator projection just as that used by
> Google maps. it seems that current version of NCL does not support WEB
> mercator map projection, so, I ask for a help about how to make some
> modifications in the NCL source code, so that it can support the WEB
> mercator projection
>
> Sincere thanks for your help
>
> Xianbiao Kang
>
>
>
>
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20180412/7bdeb69e/attachment.html>