[gdal-dev] Extract Extent or Bounding Box for a subset of shapes for a shapefile

[Chaitanya kumar CH]

Sig,

ogrinfo doesn't force the recomputation of extent. It is considered as a
costly operation. ogrinfo just reports the stored extent.
Whereas in ogr2ogr, creating a new file automatically computes the extents.

On Fri, Apr 22, 2011 at 7:44 PM, Luca Sigfrido Percich
<sigfrido at tiscali.it>wrote:

>
> Hi Matthew,
>
> Your question is interesting. ogrinfo -where seemed to be the answer,
> but...
>
> I tried ogrinfo with the -where "sql where" option with both MapInfo and
> PostGIS layers. In your case it should be:
>
> ogrinfo -ro -so -al -where "$WHERECLAUSE" "whole_shapefile.shp"
>
> The returned extent is always the same, regardless of the presence or
> composition of the -where clause, so it refers to the whole layer rather
> than to the selected features.
> (I'm using GDAL 1.9 dev)
>
> Is this the expected behaviour of ogrinfo -where "..."? Or sould -where
> affect the returned Extent too?
>
> Thank you all
>
> Sig
>
> Il giorno ven, 22/04/2011 alle 08.22 -0500, Matthew Pettis ha scritto:
> > Hi All,
> >
> >
> > I think this is the right list for the question below, as I cannot
> > find a different list that matches my question better.
> >
> >
> > I'm using ogr2ogr and ogrinfo (v1.4), and I want to extract the extent
> > from the result of a subsetting where argument.  I have a solution
> > here that works but I'm wondering if I'm missing some more obvious
> > solution.  In a bash script, I do the following (the core snippet
> > only, as I took out the shebang and option-getting/setting code:)
> >
> >
> > ---------------------------
> > rm -rf /tmp/tmpshpfile.*
> >
> >
> > ogr2ogr -where "$WHERECLAUSE" /tmp/tmpshpfile.shp "$FILE"
> >
> >
> > ogrinfo -ro -so -al /tmp/tmpshpfile.shp | \
> >     grep Extent | \
> >     tr -d '[:alpha:]:() -' | \
> >     tr ',' ' '
> >
> >
> > rm -rf /tmp/tmpshpfile.*
> > ---------------------------
> >
> >
> > I can use it as follows:
> >
> >
> > ---------------------------
> > $ ./bbox.sh -f /path/to/shp/shp_counties.shp -w "COUNTY_NAME='Yellow
> > Medicine'"
> > 226206.484375 4934737.000000313007.250000 4979500.500000
> > ---------------------------
> >
> >
> > Where the argument to '-w' is put into the '$WHERECLAUSE' variable in
> > the script.
> >
> >
> > This works.  As I wrote, though, am I missing something obvious in
> > command-line switches to either of these programs that would simplify
> > this so I wouldn't have to use this script?  Or is there some other,
> > better way of doing this?  Also, is there a way to pipe the output of
> > ogr2ogr on stdout directly to the stdin of ogrinfo?
> >
> >
> > Thanks,
> > Matt
> > _______________________________________________
> > gdal-dev mailing list
> > gdal-dev at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
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-- 
Best regards,
Chaitanya kumar CH.
/tʃaɪθənjə/ /kʊmɑr/
+91-9494447584
17.2416N 80.1426E
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