[Geojs-users] transforming geojson with crs EPSG:26986

[Jonathan Beezley]

There is a concept of a "per-layer" projection that would theoretically do
the conversion for you automatically.  I don't know that this is really
tested anywhere, so it is likely buggy.

We should make an interface for adding projection definitions.  Some thin
layer over proj4.defs would probably be sufficient.  I think we should also
add an asynchronous lookup method to load definitions on demand from
spatialreference.org.

On Mon, Apr 18, 2016 at 10:30 AM, Michael Grauer <michael.grauer at kitware.com
> wrote:

> Thanks for all the help with this guys.
>
> Aashish and I will talk later today to figure out this particular dataset
> and issue.
>
> I wrote out some questions this led me to.  Don't feel like you need to
> answer them, but they might be helpful for GeoJs development/documentation.
>
> Is there general guidance for transformations within GeoJs, or is this
> something yet to be worked out?  I.e., will there be a list of transforms
> supported by proj4j that are included in GeoJs, or maybe a path to add
> transforms such as those node-proj4js-defs within GeoJs?
>
> If I include GeoJs, proj4j is not exposed externally, so should users of
> GeoJs try to do everything through the GeoJs transform?  What is the
> recommended path to doing an arbitrary transform like what David describes?
>
>
>
>
> On Mon, Apr 18, 2016 at 8:21 AM, David Manthey <david.manthey at kitware.com>
> wrote:
>
>> There aren't many predefined tags in proj4, but
>> http://spatialreference.org lists the transform for many.  For EPSG:26986,
>> you can use "+proj=lcc +datum=NAD83 +ellps=GRS80 +lat_0=41
>> +lat_1=42.68333333333333 +lat_2=41.71666666666667 +lon_0=-71.5 +no_defs
>> +units=m +x_0=200000 +y_0=750000".
>>
>> On Mon, Apr 18, 2016 at 12:53 AM, Aashish Chaudhary <
>> aashish.chaudhary at kitware.com> wrote:
>>
>>> 26986 is a local projection (state level). It is possible that proj4 js
>>> does not have this pre-defined. I believe this demo (
>>> http://opengeoscience.github.io/geojs/examples/reprojection/) lists all
>>> the pre-defined ones. The reason you are getting this dataset because its
>>> fetching from a different server. Let me talk to you in the morning to sort
>>> this out.
>>>
>>> - Aashish
>>>
>>>
>>> On Sat, Apr 16, 2016 at 6:54 PM, Michael Grauer <
>>> michael.grauer at kitware.com> wrote:
>>>
>>>> Hi GeoJs-ers,
>>>>
>>>>
>>>> I'm getting some GeoJson back from a server like the below, but I can't
>>>> get it to display in GeoJs, using 0.9.0.
>>>>
>>>> I've tried transforming it like
>>>>
>>>> geo.transform.transformCoordinates('EPSG:26986', 'EPSG:3857',
>>>> [{x:250428.21609999985,y:921269.2148999982}]);
>>>>
>>>> and a few variations, but I'm never getting back what looks like
>>>> long/lat values, and I get exceptions like
>>>>
>>>> colorbrewer.js:312 Can't use transform source: EPSG:26986r @
>>>>
>>>>
>>>> I could grab the LATITUDE/LONGITUDE properties, but these aren't
>>>> provided for other datasets from the same server of different geometries.
>>>>
>>>> Any advice?
>>>>
>>>> Thanks,
>>>> Mike
>>>>
>>>>
>>>> http://spatialreference.org/ref/epsg/26986/
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> {"type":"FeatureCollection","totalFeatures":1,"features":[{"type":"Feature","id":"MORIS.CARCINUS_MAENAS_2010_PT.1","geometry":{"type":"Point","coordinates":[250428.21609999985,921269.
>>>> 2148999982]},"geometry_name":"SHAPE","properties":{"SITE_NAME":"Beverly
>>>> Public
>>>> Pier","TYPE":"dock","CITY":"Beverly","STATE":"MA","LATITUDE":42.54035,"LONGITUDE":-70.8861,"bbox":[250428.21609999985,921269.
>>>> 2148999982,250428.21609999985,921269.2148999982
>>>> ]}}],"crs":{"type":"name","properties":{"name":"urn:ogc:def:crs:EPSG::26986"}},"bbox":[250428.2161,921269.
>>>> 2148999979,250428.2161,921269.2148999979]}
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Geojs-users mailing list
>>>> Geojs-users at public.kitware.com
>>>> http://public.kitware.com/mailman/listinfo/geojs-users
>>>>
>>>>
>>>
>>>
>>> --
>>>
>>>
>>>
>>> *| Aashish Chaudhary | Technical Leader         | Kitware Inc.
>>>   *
>>> *| http://www.kitware.com/company/team/chaudhary.html
>>> <http://www.kitware.com/company/team/chaudhary.html>*
>>>
>>> _______________________________________________
>>> Geojs-users mailing list
>>> Geojs-users at public.kitware.com
>>> http://public.kitware.com/mailman/listinfo/geojs-users
>>>
>>>
>>
>>
>> --
>> David Manthey
>> R&D Engineer
>> Kitware Inc.
>> (518) 881-4439
>>
>
>
> _______________________________________________
> Geojs-users mailing list
> Geojs-users at public.kitware.com
> http://public.kitware.com/mailman/listinfo/geojs-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/geojs-users/attachments/20160418/8999bfb6/attachment-0001.html>