[Proj] Intro and new Excel wrapper for proj.4

Kristian Evers kreve at sdfe.dk
Thu Sep 22 01:54:32 EST 2016

Hi John,

Very cool indeed. I know of at least one that will find this useful. I've added a link to you github repo on the wiki [0]. Eventually I'll get round to putting on the website as well.

Your work on HTDP sounds interesting as well. I'll have to give it a closer look later. I wonder if there's an overlap between your work and the "transformation pipelines" [1] that Thomas are working on.


[0] https://github.com/OSGeo/proj.4/wiki
[1] https://github.com/OSGeo/proj.4/pull/388

Fra: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org] på vegne af John Buonagurio [jbuonagurio at exponent.com]
Sendt: 21. september 2016 21:18
Til: proj at lists.maptools.org
Emne: [Proj] Intro and new Excel wrapper for proj.4

Hi all,

I'm new to the list. I just finished an Excel API wrapper for
pj_transform(), which was surprisingly straightforward thanks to the
easy build with NMAKE and simple API (I can't say enough good things
about this library). Here's the GitHub page with some basic


I started this a couple years ago actually, but just recently changed it
to use the native Excel C API and added some other improvements like the
EPSG() function to return proj.4 strings from a giant switch statement
(for single file deployment / separate folder and PROJ_LIB not

I have a few improvements planned, but please let me know if you have
any suggestions or feedback:

- create an installer and chm help file
- test against GIGS
- use pj_is_latlong() so you don't have to use radians


On a somewhat unrelated note, I also started working on a library
version of NGS HTDP, and a simple wrapper to use it in R:


The library isn't quite ready for prime time just yet - need to make a
proper C binding with iso_c_binding (only works with GCC at the moment),
add the required explicit interfaces and other cleanup. At this point
the F77 code is mostly unmodified.

I know you have the crs2crs2grid.py utility to generate HTDP grids
between specific epochs, but I think it would be cool to embed HTDP in
such a way that you can provide epoch dates as parameters in the proj.4
string. Would probably take quite a bit of work to do this 'cleanly'

Thanks for the great software,

John Buonagurio

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