[GRASSLIST:919] Re: Handling millions of points in GRASS...

[Bernhard Reiter]

On Wed, Aug 06, 2003 at 09:23:56AM -0700, David Finlayson wrote:

> 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.

How to hold the data depends on your usage requirements.
If you do many queries that could benefit from sofisticated indexes
you should think about using PostGIS.
Also if you need data security.

Also check out this post comparing the upcoming geographical features
of MySQL 4.1 and postgis:
http://intevation.de/pipermail/freegis-list/2003-July/001449.html
Basically MySQL 
does not offer transactional security and nice index technology.

Radim and Sandro already pointed out that there are several
ways to get points out of the database into GRASS.

The more complicated approaches (like moving to PostGIS 
and optimising the indexing) only make sense if you really
have the usage pattern for it. I agree with Radim that cleverly used
text files might give good results.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://lists.osgeo.org/pipermail/grass-user/attachments/20030807/d05ff694/attachment.bin