[gdal-dev] convert shapefile from California State Plane to EPSG:4326

[Daniel Fenton]

Hi Maning,

For NAD83 you need to convert the Datum to WGS84. The WKT string you show
does not include that conversion. Proj.4 is missing these in a lot of cases.

Try this string instead:

PROJCS["NAD83_California_zone_5_ftUS",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137,298.257222101]],TOWGS84[-0.9956,1.9013,0.5215,0.025915,0.009426,0.011599,-0.00062],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["standard_parallel_1",35.46666666666667],PARAMETER["standard_parallel_2",34.03333333333333],PARAMETER["latitude_of_origin",33.5],PARAMETER["central_meridian",-118],PARAMETER["false_easting",6561666.667],PARAMETER["false_northing",1640416.667],UNIT["Foot_US",0.30480060960121924]]

Hopefully that works for you. Let me know if it doesn't.

Daniel Fenton
Software Engineer
Esri R&D

On Mon, Feb 8, 2016 at 6:56 AM maning sambale <emmanuel.sambale at gmail.com>
wrote:

> Hi,
>
> I'm trying to convert LA City building data from State Plane to EPSG:4326.
> I converted the data using ogr2ogr.  Visually inspecting using Bing
> imagery, I'm seeing an offset.
>
> Details of SRS info and sample images here:
> https://gist.github.com/maning/093a866fd465ea880032
>
> It is possible that Bing has the offset, but the source of Bing comes
> from LARIAC (Los Angeles Region Imagery Acquisition Consortium)
> imagery, the same source as the building footprints were traced.
>
> Any hints on the "proper" conversion from State Plane to EPSG:4326.
>
> --
> cheers,
> maning
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> https://epsg4253.wordpress.com/
> http://twitter.com/maningsambale
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