[Gdal-dev] GDAL 1.2.2 Released
Eduardo Patto Kanegae
lists at webmapit.com.br
Thu Sep 16 20:32:28 EDT 2004
On Thu, 16 Sep 2004 19:08:13 -0400, Frank Warmerdam <warmerdam at pobox.com> escreveu:
> De: Frank Warmerdam <warmerdam at pobox.com>
> Data: Thu, 16 Sep 2004 19:08:13 -0400
> Para: Eduardo Patto Kanegae <lists at webmapit.com.br>
> Assunto: Re: [Gdal-dev] GDAL 1.2.2 Released
> Eduardo Patto Kanegae wrote:
> >>SQLite Driver:
> >> - New read/write driver implemented for SQLite databases.
> > # it means will be possible to store POINTS tables on databases such
> > as MySQL, Informix, MSSQL, DB2, etc a then display these data using
> > tools like MapServer ? or it will also possible to store complex
> > geometries(line/poly's)?
> The above comment just refers to a driver being implemented for the SQLite
> database system (http://www.sqlite.org). It doesn't help with any of the
> databases you mention.
# ops... :-) ... sorry my ignorance folks. I thought sqlite was a database framewok like ADO or ODBC.
> However, OGR also has support for ODBC data connections and this has been
> used to read data from a variety of RDBMS systems. Note that the ODBC
> driver has limited support for geometries from these tables, and it is
> sometimes necessary to use the OGR VRT (virtual) driver as an extra
> layer to indicate what fields of a table from ODBC should be used as x, y
> or as well known text style geometry.
> I would suggest you read up on the VRT and ODBC OGR drivers if you are
> interested in this.
# thanks Frank,
> >>CSV Driver:
> >> - New read/write driver implemented for comma seperated value files.
> > # I never used this OGR option... what is it for? it is possible to load a CVS like:
> > POINTID;NAME;X;Y
> > 0;A;210.5;53
> > 1;B;268;9.68
> > ... and so on...
> Yes, but there is no implicit knowledge in OGR that X and Y are location
> information. This would have to be interpreted by a VRT datasource
> referring to the CSV datasource.
> I would add that your example uses semi-colons as field seperateors.
> Currently the CSV only supports _comma_ seperated value files.
> >> - Integration a series of methods utilizing GEOS when available. Note
> >> that Intersect() is still just an envelope comparison.
> > # cool... means OGR can make topological tests?
> Yes. There are methods on the OGRGeometry to do various topological
> tests now. There are also methods for converting between OGR and GEOS
> geometry formats if you want to use other GEOS capabilities directly.
> You might want to skim the OGRGeometry method list for stuff like
> Intersect(), Touches(), Overlaps(), ConvexHull(), Buffer(),
> Intersection() and Difference().
> Best regards,
> I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush | Geospatial Programmer for Rent
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