[Mapserver-users] speeding up large shapefiles

[Bart van den Eijnden]

Hi Steve,

thanks for your answer. I did not want to spend a lot of time on tiling if 
it would not make any sense. I once did this with ECW files without much 
performance gain.

How can I get shp2tile to work on Windows? Any binaries/source code 
available somewhere?

BTW what is the difference in using tile4ms and using ogrtindex?

Best regards,
Bart

On Sun, 25 Jan 2004 08:34:43 -0500, <woodbri at swoodbridge.com> wrote:

> Bart,
>
> This would definitely help. There is an OpenSource utility to assist
> in the tiling at http://imaptools.com/?tab=4 called shp2tile it has a
> lot of options to help tile the shpfile using different algorithms.
>
> If you tile the results into a directory like tiledir then you can
> run on linux:
>
> find tiledir -name "*.shp" -exec shptree {} \;
> find tiledir -name "*.shp" > tiledir.in
> tile4ms tiledir.in tiledir-tile
> shptree tiledir-tile
>
> To create spatial indexes and to create the tile index.
>
> As far as size of each tile, you are correct that there are a lot of
> variables involved. Because of the file system cache that most modern
> OSs have, you do not want to make the files too small as it will cost
> you more to open/close a lot of files than it will cost you to read
> some extra data into the file system cache.
>
> Also, if you have LOTS of attributes in your dbf file that you do not
> need for rendering then you might want to think about thinning these
> down to what you do need so you have to do less disk IO to read your
> attributes when rendering your maps.
>
> -Steve Woodbridge
>
> On 25 Jan 2004 at 13:50, Bart van den Eijnden wrote:
>
>> Hi list,
>>
>> I saw a few posts from early 2003 about speeding up large shapefiles, 
>> but
>> never found any conclusions on the subject.
>>
>> I have a question with regard to speeding up large shapefiles:
>>
>> would it make sense to split up my large (350 Mb) shapefile in tiles, 
>> and
>> then use an OGR tileindex on the tiles (with quadtree indexes on both
>> tileindex and tiles)? If so, can anything be said about an ideal tile 
>> size
>> in Mb, or is this too much dependent on the data?
>>
>> Ofcourse this will also be dependent on the area I am displaying with my
>> shapefile, and the maximum area a user can get displayed (by using the
>> MINSCALE/MAXSCALE settings in my MAP file).
>>
>> Thanks in advance for any input on this.
>>
>> Best regards,
>> Bart
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>> Mapserver-users at lists.gis.umn.edu
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>>
>
>
>



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