Hi,
The Shape driver work with qix file internally (speed up spatial
filters). You can find if qix file exist with cpl function: CPLCheckForFile
Also you can create own QuadTree with: CPLQuadTreeCreate
Best regards,
Dmitry
14.02.2014 9:39, Chaitanya kumar CH ?????:
Chuiqing,
You can create an index through SQL. This is the preferred method even
if you stick to the shapefile format for your vector data.
OGRDataSource::ExecuteSQL()
OGR's Shapefile driver supports these SQL commands among others:
CREATE SPATIAL INDEX ON layer_name [DEPTH n]
DROP SPATIAL INDEX ON layer_name
REPACK layer_name
RECOMPUTE EXTENT ON layer_name
On Fri, Feb 14, 2014 at 10:56 AM, C. Zeng <[email protected]
<mailto:[email protected]>> wrote:
Hi Chaitanya,
Thank you for your response,
I know I can do this through GDAL binary, and my question is: how
can I integrate this function into my code?
I have a platform like QGIS, I would like the program itself have
the ability to create and load .qix file. For example, when I open
the .shp file, I can detect whether there is .qix, if not then
create a new qix file;
When the user zoom the map window, it will filter the map content
via the qix file to accelerate the searching.
Does GDAL/OGR has similar functions/classes, something like
OGRSFDriverRegistrar::Createqix(savepath),
OGRSFDriverRegistrar::Loadqix(path),to open and use qix files?
Thank you,
Chuiqing,
On Thu, Feb 13, 2014 at 11:46 PM, Chaitanya kumar CH
<[email protected] <mailto:[email protected]>> wrote:
Chuiqing,
The OGR Shapefile driver supports spatial indexing through qix
files. To explicitly create a spatial index use the Create
Index command:
CREATE SPATIAL INDEX ON tablename [DEPTH N]
Depth can range from 1 to 12. You can issue the SQL command using
ogrinfo.
ogrinfo -sql 'CREATE SPATIAL INDEX ON shapefilename [DEPTH N]'
path/to/shapefile/directory
http://www.gdal.org/ogr/drv_shapefile.html -> Spatial and Attribute
Indexing.
On Fri, Feb 14, 2014 at 3:12 AM, <[email protected]
<mailto:[email protected]>> wrote:
Hi chaitanya_ch,
I know you are an expert on this, I want to know how can I
use GDAL library to implemented qix reading and using in
spatial filtering.
I have many large shape files in Gigbyte level, they are
very slow when navigating in my app. I want to use *.qix
file through GDAL library to accelerate it.
How can I do that?
Thank you,
C. Zeng
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Best regards,
Chaitanya kumar CH.
+91-9494447584 <tel:%2B91-9494447584>
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Best regards,
Chaitanya kumar CH.
+91-9494447584
17.2416N 80.1426E
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