Re: newbie postgis and google maps question

The original shape file, that I got from the Oregon Forestry Department, had this projection:

Data Type: Shapefile Feature Class
Shapefile: Z:\FSN\seedzone_pre1996\sz_orwa_pre1996.shp
Geometry Type: Polygon

Projected Coordinate System: NAD_1983_Oregon_Statewide_Lambert_Feet_Intl
Projection: Lambert_Conformal_Conic
False_Easting: 1312335.95800525
False_Northing: 0.00000000
Central_Meridian: -120.50000000
Standard_Parallel_1: 43.00000000
Standard_Parallel_2: 45.50000000
Latitude_Of_Origin: 41.75000000
Linear Unit: Foot

Geographic Coordinate System: GCS_North_American_1983
Datum: D_North_American_1983
Prime Meridian: 0
Angular Unit: Degree


So I projected that into mercator in ArcMap:

Data Type: Shapefile Feature Class
Shapefile: Z:\FSN\seedzone_pre1996\sz_orwa_pre1996_Project.shp
Geometry Type: Polygon

Projected Coordinate System: World_Mercator
Projection: Mercator
False_Easting: 0.00000000
False_Northing: 0.00000000
Central_Meridian: 0.00000000
Standard_Parallel_1: 0.00000000
Linear Unit: Meter

Geographic Coordinate System: GCS_WGS_1984
Datum: D_WGS_1984
Prime Meridian: 0
Angular Unit: Degree


I then used shp2pgsql to add this to my database:

SELECT AddGeometryColumn('members_oldzone', 'poly', 4326, 'MULTIPOLYGON', 2);
ALTER TABLE "members_oldzone" ALTER "poly" SET NOT NULL;
CREATE INDEX "members_oldzone_poly_id" ON "members_oldzone" USING GIST ( "poly" GIST_GEOMETRY_OPS );

Paul Ramsey wrote:

Your original data is probably not 4326. Do you have any clue what  
projection it is in? Where did you get it from?

P

On Jan 20, 2008, at 7:02 PM, Sam Boggess wrote:

>
> Hello,
>
> I'm new to PostGIS and this has to be a cakewalk for
> you experienced users, but your help would be greatly appreciated.  I
> have a PostGIS enabled database that contains polygon data from a
> shapefile using SRID 4326.  All I want to do at this point is mark the
> centers of all of my polygons in Google Maps.  I've written my
> query, and it works great:
>
> select astext(centroid(poly))
> from zones
>
> returns (a bunch of):
> POINT(-13057223.7425678 6208110.75868711)
>
> However, I have no idea what to do with this point data.  Google maps
> expects lat and long; how can i convert this?  In another forum a user
> suggested dividing by 10, but that's a point in Northern Canada,  
> this point
> should be in NE Washington State.
>
> Any Help would be greatly appreciated
> --
> View this message in context: http://www.nabble.com/newbie-postgis-and-google-maps-question-tp14989995p14989995.html
> Sent from the PostGIS - User mailing list archive at Nabble.com.
>
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