optimize mapserver performance

There are several ways to improve UMN-mapserver performance. These are a couple of them:

- Take care that mapserver only draws features which are visible and readable by setting proper scale-ranges for layers. If you have mapserver draw 1000s of features leaving you with a chaotic map which is onreadable, think again.

- For shapedata use the mapserver tool shptree to create a tree index for larger shapes. Mapserver uses the index to find the proper features to draw. The index is saved in shape.qix file. http://mapserver.gis.umn.edu/docs/reference/utilityreference/shptree. Very usefull is this batch file which indexes all shapes in a directory at once (save as xxx.bat and place in shape directory)

@ECHO OFF
set shptree=""
IF EXIST C:\ms4w\tools\mapserv\shptree.exe (
set shptree=C:\ms4w\tools\mapserv\shptree.exe
)

IF %shptree%=="" (
ECHO shptree.exe is missing.
GOTO:EOF
) ELSE (
GOTO loopDir
)

:loopDir
FOR /R %%A in (*.shp) do CALL :Subroutine %%A
GOTO:EOF

:Subroutine
ECHO Index: %1
%shptree% %1
GOTO:EOF

- For a set of rasters use gdaltindex (bundled with gdal/ms4w) to index the rasters into a single shape file.

- If you have a set of comparable shapes (like shapes per city in a district). Combine them into one layer using a tileindex (tile4ms tool). http://mapserver.gis.umn.edu/docs/reference/utilityreference/tile4ms. Tile4ms uses an input file with all the shape titles to combine. This input file can be generated with a dos-command

dir /b /s *.shp > metafile.txt

If you ever decide to move the shapes to another location. Remember to update the tileindex-dbf since it contains file references.

If you have a very large shape, it's sometimes faster to cut the shape in parts and combine the parts using tile4ms. Imaptools has created a tool, shp2tile, which can automatically slice a big shape into a set of tiles. Shp2tile as windows binary is included in ms4w.