[PROJ] Newbie question on projections

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[PROJ] Newbie question on projections

Daniel Suson

I have a project that takes spherical maps (either Terrestrial or astronomical) as its input. The inputted data is stored in a "flat" 360x180 (scaled up or down depending upon the resolution) 2-D array. As an early step in the process I then display the map in one of the basic projections (currently Mollweide, but I would like to support others). I am hoping that I can use PROJ4 to transform this into another 2-D array that can then be passed into the display routines.

  1. Is this something that PROJ4 can do?
  2. If so, can this capability be called as a library function from within the program?
  3. If not, is there another library I should consider to support this need?

Thank you for your help with this.


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Re: Newbie question on projections

Paul Ramsey
Proj will convert double arrays of longitude/latitudes into Mollweide, if that’s the question? It’ll also convert into a whole zoo of other interesting global projections, if you’re looking for alternatives. It can be called as a library https://proj4.org/development/quickstart.html

On May 23, 2019, at 10:14 AM, Daniel Suson <[hidden email]> wrote:

I have a project that takes spherical maps (either Terrestrial or astronomical) as its input. The inputted data is stored in a "flat" 360x180 (scaled up or down depending upon the resolution) 2-D array. As an early step in the process I then display the map in one of the basic projections (currently Mollweide, but I would like to support others). I am hoping that I can use PROJ4 to transform this into another 2-D array that can then be passed into the display routines.

  1. Is this something that PROJ4 can do?
  2. If so, can this capability be called as a library function from within the program?
  3. If not, is there another library I should consider to support this need?

Thank you for your help with this.

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https://lists.osgeo.org/mailman/listinfo/proj


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Re: Newbie question on projections

Alan Snow
Depending on your end goal, I would recommend using GDAL to reproject 2D data. This will resample your data from a 2D grid in one projection to a 2D grid in a new projection.

If you are a Python user, I would recommend:

Hopefully this helps,
Alan

On Thu, May 23, 2019 at 12:42 PM Paul Ramsey <[hidden email]> wrote:
Proj will convert double arrays of longitude/latitudes into Mollweide, if that’s the question? It’ll also convert into a whole zoo of other interesting global projections, if you’re looking for alternatives. It can be called as a library https://proj4.org/development/quickstart.html

On May 23, 2019, at 10:14 AM, Daniel Suson <[hidden email]> wrote:

I have a project that takes spherical maps (either Terrestrial or astronomical) as its input. The inputted data is stored in a "flat" 360x180 (scaled up or down depending upon the resolution) 2-D array. As an early step in the process I then display the map in one of the basic projections (currently Mollweide, but I would like to support others). I am hoping that I can use PROJ4 to transform this into another 2-D array that can then be passed into the display routines.

  1. Is this something that PROJ4 can do?
  2. If so, can this capability be called as a library function from within the program?
  3. If not, is there another library I should consider to support this need?

Thank you for your help with this.

_______________________________________________
PROJ mailing list
[hidden email]
https://lists.osgeo.org/mailman/listinfo/proj

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[hidden email]
https://lists.osgeo.org/mailman/listinfo/proj


--
Alan Snow

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