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

[Michael Grauer]

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
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/geojs-users/attachments/20160418/012411f5/attachment.html>