[MetaCRS] [Proj4js] geocent proj issue.

[Paul Ramsey]

You know what would be cool? Downloading the part of the grid you need
from a WCS (and by "cool" I mean, "unbearably doctrinaire from a
standards point-of-view")

P

On Fri, Sep 10, 2010 at 8:02 PM, Mike Adair <madair at dmsolutions.ca> wrote:
> Hi Clement,
>
> There aren't any plans to support grid shift files currently.  The main
> issue is downloading some potentially large files to the client.
>
> Mike
>
>
> On 9/10/2010 3:29 AM, Clément Ronzon wrote:
>
> Hi Mike,
>
> I'm going to check the PROJ.4 files to reproduce the geocent behavior you
> described.
> I'll keep you in touch.
>
> I've another question about "nadgrids" this time: do you know if Proj4js
> could be able to handle nadgrids files ? May be using Ajax requests...
>
> Thanks for your help!
> Sincerely,
> Clément Ronzon
> 151 Av. Félix Faure
> 69003 LYON, FRANCE
> Tel. # : +33 (0)9 54 43 12 20
> Fax # : +33 (0)9 59 43 12 20
> Cell. # : +33 (0)6 08 21 23 27
> http://twcc.free.fr
> http://www.grottocenter.org
> http://www.zakbag.com
>
>
> On Thu, Sep 9, 2010 at 8:51 PM, Mike Adair <madair at dmsolutions.ca> wrote:
>>
>> Hi Clement,
>>
>> The contents of the old geocent.js file is now contained in the main
>> proj4js.js file and it mainly handled conversions to/from
>> geocentric/geodetic coordinates.
>>
>> I assume you are trying to convert from geocentric to Lat/long coords?  I
>> see that PROJ.4 handles that case where the geocent 'projection' is defined
>> with the identity transform (like you have done) but i don't think that will
>> work in Proj4js.  You may be able to step through a transformation and see
>> where the geocentric - geodetic transform occurs and where any errors may be
>> introduced.
>>
>> Mike
>>
>>
>>
>> On 9/8/2010 6:54 AM, Clément Ronzon wrote:
>>
>> Hi everyone!
>>
>> I'm new on this mailing list, so I'll introduce myself in a few words: my
>> name is Clément Ronzon, I'm living in France but I'm going to move to Mexico
>> in a few months, I'm working in Informatics design and development for
>> France Telecom, and I'm the developer of TWCC (http://twcc.free.fr).
>>
>> I have a question about geocent projections.
>> I have the following definition :
>> Proj4js.defs["IGNF:AMST63"] = "+title=Ile d'Amsterdam 1963 +proj=geocent
>> +towgs84=109.7530,-528.1330,-362.2440 +a=6378388.0000 +rf=297.0000000000000
>> +units=m +no_defs";
>>
>> But when proj4js tries to load the geocent proj file it fails because
>> there is no geocent.js file. Actually I found that this file has been
>> removed (http://trac.osgeo.org/proj4js/ticket/16).
>>
>> So I tried to create /lib/projCode/geocent.js with this content:
>> Proj4js.Proj.geocent = {
>>     GEOCENT_LAT_ERROR:0x0001,
>>   init: function() {
>>     //no-op
>>   },
>>   forward: function(pt) {
>>     //identity transform
>>     return pt;
>>   },
>>   inverse: function(pt) {
>>     //identity transform
>>     return pt;
>>   }
>> };
>>
>> But it seems that the result of transformations is wrong (some meters on X
>> and Y).
>> Could someone tell me how can I solve this issue please ?
>>
>> Thanks in advance! And, by the way, congratulations for those metaCRS
>> projects!!!
>> Clément Ronzon
>> 151 Av. Félix Faure
>> 69003 LYON, FRANCE
>> Tel. # : +33 (0)9 54 43 12 20
>> Fax # : +33 (0)9 59 43 12 20
>> Cell. # : +33 (0)6 08 21 23 27
>> http://twcc.free.fr
>> http://www.grottocenter.org
>> http://www.zakbag.com
>>
>> _______________________________________________
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>>
>> --
>>    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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>> MetaCRS at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/metacrs
>>
>
>
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>
> --
>    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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