[GRASSLIST:916] Re: Handling millions of points in GRASS...

[Sandro Klippel]

David,

On grass 5.0 do you not need postgis, only the postgres is necessary.
The standard postgresql have some geometry types already (point,
polygon, line,..) and operators for it (inside, overlap,..). Conversion
between pair of floats (x, y) and point type is easy. With the grass
module 'd.site.pg' you can load the points specified by a sql query and
then interpolate it. Areas and lines can be loaded from grass to
postgres by the module 'v.to.pg' and then used in sql queries.

I think that grass-odbc-mysql does not have those features.

Sandro. 

On Wed, 2003-08-06 at 13:23, David Finlayson wrote:
> I have a bathymetry project that is attempting to collect and map every 
> sounding ever collected for Puget Sound, Washington. So far, I have 
> several million soundings stored in a MySQL database. But with the new 
> Sonar aboard our vessel, the new interest in bathymetric LIDAR and 
> cooperation with NOAA, that number is expected to grow exponentially in 
> the next few years.
> 
> What is the best way to get this data into GRASS?  What's the best way 
> to manage it?
> 
> I know that RDBMS support is coming soon and that (apparently) PostGIS 
> is already functional on some platforms (Linux, Cygwin?).  But what is 
> the word from the trenches?  I have been very happy with MySQL and would 
> rather use this if functionality is comparable to PostGres, but it would 
> be better to move now rather than wait if necessary...
> 
> A major task that needs to be handled is some way to select points both 
> by spatial location (polygons not boxes) and by attributes such as age, 
> survey, and platform.  Currently, I have a table of soundings (x,y,z,ID) 
> and a table of headers  (ID,date,platform,etc.) and I load it into 
> ArcGIS (ESRI, inc.) through ODBC where I can grid up the data into 
> rasters for further analysis. Hence, I am currently dependent on Windows.
> 
> Thanks for your thoughts.
> 
> -- 
> David Finlayson
> School of Oceanography
> Box 357940
> University of Washington
> Seattle, WA  98195-7940
> USA
> 
> Office: Marine Sciences Building, Room 112
> Phone: (206) 616-9407
> Web: http://students.washington.edu/dfinlays
-- 
Sandro Klippel <sandro.klippel at talha-mar.com.br>

talha-mar projetos ambientais
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