Add custom projection

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Add custom projection

raulfalco
Hi,
I work for a company where we have our custom mercator projection.
I already developed code snippets to integrate such projection in proj4 4.8.0  (c++).
Is there the chance to collaborate with develop team to integrate it in proj4 main trunk?

Thanks and best regards,

Raul Pra Levis


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Re: Add custom projection

support.mn
Hello,

could you tell us why do you have a custom mercator
projection? and what is custom in it?

Regards: Janne.

===========================================

raul pra levis [[hidden email]] kirjoitti:

>
>
>
> Hi,
> I work for a company where we have our custom mercator projection.
> I already developed code snippets to integrate such projection in proj4 4.8.0  (c++).
> Is there the chance to collaborate with develop team to integrate it in proj4 main trunk?
>
> Thanks and best regards,
>
> Raul Pra Levis
>
>
>      
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj


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Re: Add custom projection

raulfalco
Hi Janne,
thanks for the response.
Our custom projection is an approximated Mercator Meter projection based on International 1909 ellipsoid.
The approx formula is:

y = ln ( tan(1/2 * atan(tan(lat_rad) /  1.0067642927) + PI/2) ) * 6378388.0


The choice of using an approximated projection is historical and related by hardware limitations of thirty years ago.

Regards,

Raul


> Date: Fri, 28 Mar 2014 21:52:28 +0200

> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Proj] Add custom projection
>
> Hello,
>
> could you tell us why do you have a custom mercator
> projection? and what is custom in it?
>
> Regards: Janne.
>
> ===========================================
>
> raul pra levis [[hidden email]] kirjoitti:
> >
> >
> >
> > Hi,
> > I work for a company where we have our custom mercator projection.
> > I already developed code snippets to integrate such projection in proj4 4.8.0 (c++).
> > Is there the chance to collaborate with develop team to integrate it in proj4 main trunk?
> >
> > Thanks and best regards,
> >
> > Raul Pra Levis
> >
> >
> >
> > _______________________________________________
> > Proj mailing list
> > [hidden email]
> > http://lists.maptools.org/mailman/listinfo/proj
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj

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Re: Add custom projection

José Alberto Gonçalves
Hi

I suppose it should be PI/4 instead of PI/2.
That formula is an approximation of the exact Mercator projection for the Hayford ellipsoid.
The differences in the Y coordinate are smaller than 10 meters, for latitudes below 60 degrees. If that is ok for you you can go for the ellipsoid projection::
+proj=intl +proj=merc

If you need more accuracy and your latitude extension is relatively small you can adjust a scale factor and a false northing, and get a much better accuracy.
This may avoid programming the formula.

Regards

José Gonçalves





2014-04-01 15:38 GMT+01:00 raul pra levis <[hidden email]>:
Hi Janne,
thanks for the response.
Our custom projection is an approximated Mercator Meter projection based on International 1909 ellipsoid.
The approx formula is:

y = ln ( tan(1/2 * atan(tan(lat_rad) /  1.0067642927) + PI/2) ) * 6378388.0


The choice of using an approximated projection is historical and related by hardware limitations of thirty years ago.

Regards,

Raul


> Date: Fri, 28 Mar 2014 21:52:28 +0200
> From: [hidden email]
> To: [hidden email]
> Subject: Re: [Proj] Add custom projection

>
> Hello,
>
> could you tell us why do you have a custom mercator
> projection? and what is custom in it?
>
> Regards: Janne.
>
> ===========================================
>
> raul pra levis [[hidden email]] kirjoitti:
> >
> >
> >
> > Hi,
> > I work for a company where we have our custom mercator projection.
> > I already developed code snippets to integrate such projection in proj4 4.8.0 (c++).
> > Is there the chance to collaborate with develop team to integrate it in proj4 main trunk?
> >
> > Thanks and best regards,
> >
> > Raul Pra Levis
> >
> >
> >
> > _______________________________________________
> > Proj mailing list
> > [hidden email]
> > http://lists.maptools.org/mailman/listinfo/proj
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj

_______________________________________________
Proj mailing list
[hidden email]
http://lists.maptools.org/mailman/listinfo/proj


_______________________________________________
Proj mailing list
[hidden email]
http://lists.maptools.org/mailman/listinfo/proj