Re: [Openev-discuss] List of all support files related to ESRI shape files?

[Frank W. <war...@po...>]

On 1/10/06, Jenkins, Bart (NE) <Bar...@gd...> wrote:
>
> All,
>   I've downloaded various .shp files for viewing into OpenEV and see that=
 it
> is really a set of files that, in total, describes the data set and vario=
us
> supporting information.  Can anyone tell me or point me to the TOTAL list=
 of
> all the different file types and extensions that OpenEV processes when
> reading datasets?  Specifically, I'm wondering if there is a way to
> associate a Map Projection (NAD83, WGS84) and a Datum with a dataset, in =
a
> file, that will be picked up automatically when i load the dataset.

Bart,

I believe that OpenEV currently ignores coordinate system information
for vector layers.  This is a significant deficiency compared to rasters
which are reasonably sophisticated about coordinate system support.

> Otherwise, I have to use some python code and create a SpatialReference
> object to get the projection I need.

I don't think setting the coordinate system on a vector layer
(ie. GvShapesLayer) will accomplish anything.  But you can
set it on the map after loading the vectors, and then get
proper handling.

To set the coordinate system on the GvViewArea you
should call the set_projection() method with the WKT
(well known text) description of the coordinate system.

For WGS84 you can use:

GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS
84",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["degree",0.017453292=
5199433]]

For NAD83 you can use:

GEOGCS["NAD83",DATUM["North_American_Datum_1983",SPHEROID["GRS
1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532=
925199433]]

Note that NAD83 and WGS84 are geographic coordinate
systems, and not properly referred to as projections.  They
are essentially "unprojected".

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.c=
om
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent