Sorts a Shape data set based on a single column in ascending or descending order. Supports INTEGER, DOUBLE and STRING column types. Useful for prioritizing shapes for rendering and/or labeling.
The idea here is that if you know that you need to display a certain attribute classed by a certain value, it will be faster for MapServer to access that value if it is at the beginning of the attribute file.
sortshp [infile] [outfile] [item] [ascending|descending]
This example uses a roads file ('roads_ugl') that has a field with road classes in integer format ('class1').
sortshp roads_ugl roads-sort class1 ascending
A new Shape data set named 'roads-sort.shp' is created with shapes sorted in ascending order, according to the values in the 'class1' field, as shown below.
Figure1: Attributes Before sortshp
Figure2: Attributes After sortshp