Application Data

[Giridhar Manepalli]

Thanks a lot all of you for your help. I will work on it and soon let
you know, what I experienced.


On Fri, 18 Mar 2005 12:03:18 +0100, Arnulf Christl
<arnulf.christl at ccgis.de> wrote:
> Giridhar Manepalli wrote:
> > Hello All,
> > I would like to appreciate Bart who is on the list for helping me get
> > in touch with some of the concepts of GIS and Mapserver.
>
> Bart should be awarded something on the OpenGeoSpatial. Its a pity he is
> not coming!
>
> [...]
> > Imagine that the above data is huge (as large as 100GB), so I need to
> > dump this information to a database.
>
> The sheer size of the data is not a problem for either PostgreSQL or
> PostGIS. But as Stephen and Brent suggest it *is* a problem to try start
> optimizing and tuning the database with the full load. Start as
> suggested with smaller sections.
>
> Be aware that when requesting such a large dataset it is important that
> you know what functionality you want to use. We have learned a few weeks
> ago that a feature request (WFS) can be a performance killer although
> map requests (WMS) on the same MapServer and the database are perfectly
> fast.
>
> > I would like to know, how to use this data from a table to Map it onto
> > a MAPServer.
>
> One of many ways to do it:
> - Upload CSV text file into the database
> - Create new geometry column with AddGeometryColumn
> - Write an SQL which combines and copies the x and y columns with
> AddGeometryFromText into the new geometry column.
> The SQL can be qute ugly depengding on how many intermediate steps you
> need to put together the WKS string.
>
> if the the col 'objgeom' (TEXT) contains values like: "(7.15 55.8)"
> update test set the_geom = GeometryFromText('POINT '|| objgeom || '"', 4326)
>
> if the the col 'objgeom' (TEXT) contains values like: "7.15 55.8"
> without the brackets:
> update test set the_geom = GeometryFromText('POINT ('|| objgeom || ')"',
> 4326)
>
> Another way to do it:
> Create a shape file from the data with somme other tool and load it into
> PG/PostGIS using shp2pgsql.
>
> ***
>
> I just saw that Jim already pointed you to all the docs. One more thing:
> Never forget to create a GIST index on the geometry column and vacuum
> analyze the database to make it take effect.
>
> Best, Arnulf.
>
> --
> ------------------------
> Arnulf B. Christl
> ------------------------
> http://www.ccgis.org
> http://www.mapbender.org
> ------------------------
>