[gdal-dev] Re: Performance of reading large polygons with holes

[Even Rouault]

> Hi,
> 
> Ok, this is interesting for several reasons :
> 
> 1) Trying to run the 'ogrinfo -sql "select max(OGR_GEOM_AREA) from tpi_1"
> tpi_1.shp' showed that a badly written optimization in OGR 1.9.0 broke such
> a query. Now fixed per http://trac.osgeo.org/gdal/ticket/4633
> 
> 2) Width GDAL trunk, 1.9, 1.8 and 1.7, I never get Martin's result. I
> always get :
> 
>   MAX_OGR_GEOM_AREA (Real) = 70726589354.8597
> 
> Reached on shape index = 289 (first shape is index = 0):
> 
> OGRFeature(tpi_1):289
>   id (Real) = 904743.0000000000000000000000000000000
>   gridcode (Real) = 4.0000000000000000000000000000000
>   class_name (String) = Plains or Open Slopes
> 
> I though it could come from a compiler issue, but I get the same results
> with GCC 4.4.3 in debug and optimized mode,  and also with MSVC 2008
> 
> 3) This runs in about ~ 5 seconds on all those versions on my machine
> (after several runs so that the I/O cache is hot)
> 
> OS: Ubuntu 10.04 64bit
> CPU : Intel(R) Core(TM) i5 CPU 750  @ 2.67GHz
> RAM : 4 GB

I've just tried with http://tsusiatsoftware.net/jeql/files/jeql-0.11.zip and I 
get the following results :

time java -cp commons-
lang-2.6.jar:h2.jar:javaproj-1.0.6.jar:jcommon-1.0.16.jar:jeql-0.11.jar:jfreechart-1.0.13.jar:jts-1.12.jar:jtsio-1.12.jar:proj4j-0.1.0.jar:stax2-2.1.jar:stax-
api-1.0.1.jar:wstx-lgpl-3.2.7.jar -Xms256M -Xmx1024M jeql.JeqlCmd script.jql
col0:Double 
70726589354,85522

real	8m30.478s
user	8m29.480s
sys	0m0.530s

I've also inserted that shape into a Spatialite and PostGIS DB and they also 
return very close areas with their ST_Area() implementation.

So I'm not sure that Martin and I are working on the same shapefile...

Here is mine :

-rw-r--r--   1 even even  322589721 2012-04-21 06:52 tpi_1.dbf
-rw-r--r--   1 even even        893 2012-04-21 07:03 tpi_1.prj
-rw-r--r--   1 even even  389028108 2012-04-21 06:53 tpi_1.shp
-rw-r--r--   1 even even    8039716 2012-04-21 06:52 tpi_1.shx

$ md5sum tpi_1.shp
c50c502cae5b172e270dc02e8562c69c  tpi_1.shp


> 
> Best regards,
> 
> Even
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