[postgis-users] migrating tables to postgis

[MarkW]

Now that you have data in columns in Postgresql, you can use SQL statements
to create your spatial data. Here are the steps:
1) identify your SRID/ spatial reference system
2) create geometries by passing your x and y with a spatial ref to the right
function, and
3) add a row to the geometry_columns table so that other applications can
more easily see the spatial data.

1) It's much easier if you can match your coordinate system to the right UTM
srids in the spatial_ref_sys table; see spatialreference.org for help.
2) See this function:
http://www.postgis.org/docs/ST_GeomFromText.html
(and to prove it works, the reverse is ST_X or ST_Y) to get X,Y back out )
3)
http://postgis.refractions.net/docs/ch04.html#Manual_Register_Spatial_Column
(but also see the help under 'AddGeometryColumn (
http://postgis.refractions.net/docs/AddGeometryColumn.html)

Hope this helps.

Mark


On Tue, Jan 18, 2011 at 3:37 PM, John Callahan <john.callahan at udel.edu>wrote:

> I apologize for asking what seems like an easy question.   I'm really just
> getting started with PostGIS and not sure which way to go here.   I have a
> two tables in MS Access format.  They are:
>
> Table1: StationID, easting, northing, elevation, etc...
> Table2: StationID, data values...
>
> Table1 is basically an inventory of all our stations.  Table2 is a subset
> that includes only stations we have certain data for.   How would I convert
> these into a point data set (of Table2 stations) in PostGIS?   I was able to
> copy the tables from Access into Postgres. Where would I go from here?
> Maybe OGR would help going directly from Access (or text exports of Access)
> into PostGIS?
>
> I am using Postgres 9.0.2/PostGIS 2.0.0 on Windows, and using Quantum GIS
> for viewing.  Thanks for any guidance.
>
> - John
>
> **************************************************
> John Callahan, Research Scientist
> Delaware Geological Survey, University of Delaware
> URL: http://www.dgs.udel.edu
> **************************************************
>
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