[gdal-dev] Re: ogrtindex take only one feature from a layer

[Jukka Rahkonen]

easyl <thlin.box <at> gmail.com> writes:

> But will a huge merged shapeflle take a long time to load in a Mapserver?
> since I have really a lot of shapefiles to merge. 
> 
> I just thought the ogrtindex may help. :)

Hi,

Ogrtindex can help you. We are having one dataset which contains a few hundred
shapefiles, and because we receive the updates in the same way we prefer keeping
them separate instead of combining all data together. In addition we would be
close to reach the size limit of shapefile, max 4 GB for the .shp part of a
shapefile

What we do is
- run shptree for each shapefile
- run ogrtindex
- run shptree also for the index shapefile if it is big
- use the index shapefile as Mapserver data source. 

Partial data updates are simple to do if data are delivered always in the same
way. Just write the new shapefile and the .qix index over the old files. There
is no need to touch the ogrtindex file 

Mapserver documentation at http://mapserver.org/optimization/tileindex.html is
valid.

I do not believe there is any big difference in speed when using either one big
shapefile or a ogrtileindex layer but it depends a bit on the data. Tileindex
cannot be effective if original shapefiles are overlapping a lot.

-Jukka Rahkonen-