RasterAnnotations
The annotations layer provides an excellent mechanism for automatically placing labels and symbols. For some uses, however, you may want a symbol with effectively no label at all. Unfortunately, many mechanisms for attempting this result in neither the symbol nor the label to display. The following method allows for no (visible) label while still rendering symbols at automatically selected locations.
LAYER
NAME "shields"
DATA shield_file
STATUS default
TYPE annotation
CLASS
TEXT ' '
STYLE
SYMBOL [shieldtype]
END
LABEL
MINFEATURESIZE auto
MINDISTANCE 10
REPEATDISTANCE 250
POSITION CC
END
END
END
Note the key here being the space character (not empty quotes) for the specified text