[mapserver-users] Using a attribute substring for labeling

[lars lingner]

Hello,

while using a ShapeFile, created with gdaltindex, as data source for a
layer I'd like to use a substring of the location attribute for labeling.

I could (and probably will) preprocess the ShapeFile to add the label
text as additional attribute. But I wanted to try this step within
MapServer first.

My current example contains a path and file name. The file name has a 4
digit number in it I would like to use as label. To make it more
complicated, the substring has various positions within the whole string.
Maybe there is a way with tostring() which accepts sprintf formatting,
but I couldn't figure out the correct syntax yet.

With a database layer of course I would be able to use SQL to extract a
substring and pass it as additional attribute, but not with a ShapeFile.

Is there a way to extract a substring from an attribute value and use it
as label? It would be nice to have a function available to use in
EXPRESSION or TEXT parameter.

Thank you in advance for any hints.

Lars