Enables debugging of the class object. Verbose output is generated and sent to the standard error output (STDERR) or the MapServer logfile if one is set using the LOG parameter in the WEB object.
Four types of expressions are now supported to define class membership. String comparisons, regular expressions, simple logical expressions, and string functions. If no expression is given, then all features are said to belong to this class.
String comparisons are case sensitive and are the fastest to evaluate. No special delimiters are necessary although string must be quoted if they contain special characters. (As a matter of good habit, it is recommended you quote all strings).
Regular expressions function just like previous versions of MapServer. However, you must now delimit a regular expression using /regex/. No quotes should be used.
Logical expressions allow you to build fairly complex tests based on one or more attributes and therefore are only available with shapefiles. Logical expressions are delimited by parentheses “(expression)”. Attribute names are delimited by square brackets “[ATTRIBUTE]”. These names are case sensitive and must match the items in the shapefile. For example: EXPRESSION ([POPULATION] > 50000 AND ‘[LANGUAGE]’ eq ‘FRENCH’) ... The following logical operators are supported: =,>,<,<=,>=,=,or,and,lt,gt,ge,le,eq,ne. As you might expect this level of complexity is slower to process.
One string function exists: length(). This obviously computes the length of a string. An example follows:
EXPRESSION (length('[NAME_E]') < 8)
String comparisons and regular expressions work from the classitem defined at the layer level. You may mix expression types within the different classes of a layer.
Allows for grouping of classes. It is only used when a CLASSGROUP at the LAYER level is set. If the CLASSGROUP parameter is set, only classes that have the same group name would be considered at rendering time. An example of a layer with grouped classes might contain:
LAYER
...
CLASSGROUP "group1"
...
CLASS
NAME "name1"
GROUP "group1"
...
END
CLASS
NAME "name2"
GROUP "group2"
...
END
CLASS
NAME "name3"
GROUP "group1"
...
END
...
END # layer
Maximum scale at which this CLASS is drawn. Scale is given as the denominator of the actual scale fraction, for example for a map at a scale of 1:24,000 use 24000. Implemented in MapServer 5.0, to replace the deprecated MAXSCALE parameter.
See also
Minimum scale at which this CLASS is drawn. Scale is given as the denominator of the actual scale fraction, for example for a map at a scale of 1:24,000 use 24000. Implemented in MapServer 5.0, to replace the deprecated MINSCALE parameter.
See also
The symbol name or number to use for all features if attribute tables are not used. The number is the index of the symbol in the symbol file, starting at 1, the 5th symbol in the file is therefore symbol number 5. You can also give your symbols names using the NAME keyword in the symbol definition file, and use those to refer to them. Default is 0, which results in a single pixel, single width line, or solid polygon fill, depending on layer type.
You can also specify a gif or png filename. The path is relative to the location of the mapfile.
You can also “stack” 2 symbols to achieve interesting effects. You define the second symbol, which effectively sits “on top” of the symbol normally defined above. See Cartographic Symbol Construction with MapServer for more information.
The following parameters allow you to define the symbol, and they are equivalent to their non-overlay counterparts: