[MetaCRS] Proj4js: Converting from EPSG:4326 -> EPSG:28193 fails
Mike Adair
madair at dmsolutions.ca
Tue Mar 24 15:45:21 EDT 2009
The projection class code supported by Proj4js is listed here:
http://trac.osgeo.org/proj4js/wiki/UserGuide#Supportedprojectionclasses
The ones that are listed as 'validated' have been tested against some
test points and I feel pretty confident that they are working
correctly. This list should cover the most common projections I've
encountered.
The ones listed as 'not validated' (these seem to be mostly in the
PROJ4/nad/esri file) have projection code available but they don't match
up against test points. I would like to get these fixed and validated
before we do a 1.0 final release of Proj4js.
Then there are other projections supported by PROJ4 that aren't on
either list, such as cass, that I've never had need for, so never
implemented. If there is a need I could do the work but that requires
me finding some free time to do that, others are welcome to contribute
that way as well.
Mike
Josh Rosenthal wrote:
> Unfortunately, having the conversion be accessible in a lightweight
> webapp/hta was part of the basic idea (to say nothing about javascript
> being the primary development I'm comfortable with), and as such I
> think I'm stuck. How much of proj.4 is missing from proj4js? Did I
> just pick the odd one out, or is it a fair variety of proj.4? (ie: how
> likely am I to run into this for other projects?)
>
> Josh
>
> On Tue, Mar 24, 2009 at 3:10 PM, Christopher Schmidt
> <crschmidt at metacarta.com <mailto:crschmidt at metacarta.com>> wrote:
>
> On Tue, Mar 24, 2009 at 12:02:27PM -0700, Hugues Wisniewski wrote:
> > Hi,
> >
> > I don't know if you'd be interested in this but CsMap supports
> this Cassini projection and the system 28193
> > You can access the CsMap API or if you have access to the
> MapGuide MgCoordinateSystem API that is a wrapper around CsMap you
> can do it too
>
> Proj.4 does as well; but neither proj.4 nor CsMap are accessible in
> Javascript.
>
> -- Chris
>
> > Hugues
> >
> > From: metacrs-bounces at lists.osgeo.org
> <mailto:metacrs-bounces at lists.osgeo.org>
> [mailto:metacrs-bounces at lists.osgeo.org
> <mailto:metacrs-bounces at lists.osgeo.org>] On Behalf Of Josh Rosenthal
> > Sent: Tuesday, March 24, 2009 9:45 AM
> > To: Mike Adair
> > Cc: metacrs at lists.osgeo.org <mailto:metacrs at lists.osgeo.org>
> > Subject: Re: [MetaCRS] Proj4js: Converting from EPSG:4326 ->
> EPSG:28193 fails
> >
> > Hi Mike,
> >
> > Thanks a lot. I couldn't figure out if I was doing something
> wrong or... In any case, you said 'yet'. Is there a timeline as
> to when we could expect cassini projections to be supported, or do
> you have any other suggestions as to how to convert coordinates
> to/from that? Curiously, it appears as though
> spatialreference.org
> <http://spatialreference.org><http://spatialreference.org> does
> support those reprojections, though I'm not sure what the back end
> is over there.
> >
> > In any case, any advice would be welcome,
> >
> > Thanks,
> >
> > Josh
> > 2009/3/24 Mike Adair <madair at dmsolutions.ca
> <mailto:madair at dmsolutions.ca><mailto:madair at dmsolutions.ca
> <mailto:madair at dmsolutions.ca>>>
> > Josh,
> >
> > The cassini projection code ("proj=cass") hasn't been
> implemented in Proj4js yet.
> >
> > Mike
> >
> >
> > Josh Rosenthal wrote:
> > Hi Folks,
> >
> > I hope I'm sending this to the right list. Apologies if not.
> >
> > I'm hitting a bit of a problem with a proj4js conversion, and
> I'm hoping someone can help. I'm trying to go from EPSG 4326 to
> 28193, and I'm just getting my original coordinates returned. As
> per http://spatialreference.org/ref/epsg/28193/ , I have the
> proj4js definition for 28193 as:
> > Proj4js.defs["EPSG:28193"] = "+proj=cass
> +lat_0=31.73409694444445 +lon_0=35.21208055555556 +x_0=170251.555
> +y_0=1126867.909 +a=6378300.789 +b=6356566.435
> +towgs84=-275.722,94.7824,340.894,-8.001,-4.42,-11.821,1 +units=m
> +no_defs";
> >
> > To demonstrate, I've modified the converter in the proj4js
> homepage to also have 28193 (Old Israel Grid/Palestine 1923) and
> 2039 (New Israel Grid). You can see the demo here:
> http://arkeotech.googlepages.com/Proj4js.htm
> > Converting the coordinates 35,31 from 4326 to 2039 works fine,
> but from 4326 to 28193 just returns 35,31. Looking at the spatial
> reference page for 28193, you can use the viewer to get an
> approximation for those coordinates... it should be somewhere
> roughly around 149353, 1046172
> >
> > Any thoughts?
> >
> > Thanks,
> >
> > Josh
> >
> >
> >
> ------------------------------------------------------------------------
> >
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> >
> >
> > --
> > Michael Adair
> > Senior Software Architect
> > DM Solutions Group Inc.
> >
> > Office: (613) 565-5056 x26
> > madair at dmsolutions.ca
> <mailto:madair at dmsolutions.ca><mailto:madair at dmsolutions.ca
> <mailto:madair at dmsolutions.ca>>
> > http://www.dmsolutions.ca
> > http://research.dmsolutions.ca
> >
> >
>
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>
>
> --
> Christopher Schmidt
> MetaCarta
>
>
--
Michael Adair
Senior Software Architect
DM Solutions Group Inc.
Office: (613) 565-5056 x26
madair at dmsolutions.ca
http://www.dmsolutions.ca
http://research.dmsolutions.ca
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