[Mapserver-users] Building a legend - with class objects in layers

[Norbert Thieme]

Richard Orchard schrieb:
> hi,
> 
> I am using mapserver to display some geology datasets.
> 
> A particular layer has multiple classes in order to show the various
> features (different rock types).  The features are color-coded, therefore, i
> need each feature (class) to display in the legend.
> 
> However, when the legend is generated, it just creates one item, based on
> the layer name.  it doesn't iterate through the various class objects.
> 
> Is this the way it is supposed to work?  Or is there a way to get it to
> create a legend item for each class item within a layer.  At present i am
> creating new layer objects for each item i want to display.  I have put the
> map file i am using at the bottom of this email.
> 
> Thanks in advance,
> 
> 
> Richard
> 
> 
> 
> 
> ---- mapfile
> 
> 
> MAP
>   NAME "Australia - General Information"
>   STATUS ON
>   EXTENT 109.337 -44.387 158.742 -8.8081
>   SIZE 400 300
>   SHAPEPATH "D:\webs\www3\gis_data\australia"
>   SYMBOLSET "D:\webs\www3\mapserver\etc\symbols.sym"
>   FONTSET "D:\webs\www3\mapserver\etc\fonts.txt"
>   IMAGETYPE PNG
>   IMAGECOLOR 255 255 255
>   UNITS DD
>   #
>   # Start of web interface definition
>   #
>   WEB
>     MINSCALE 2e+06
>     MAXSCALE 5e+07
>     #
>     # On Windows systems, /tmp and /tmp/ms_tmp/ should be created at the
> root
>     # of the drive where the .MAP file resides.
>     #
>     IMAGEPATH "D:/webs/www3/temp/"
>     IMAGEURL "/temp/"
>   END
>   #
>   #
>   # Start of querymap object
>   #
>   QUERYMAP
>     STATUS OFF
>     SIZE -1 -1
>     COLOR 255 0 0
>     STYLE HILITE
>   END
>   #
>   # Start of legend object
>   #
>   LEGEND
>     STATUS ON
>     IMAGECOLOR 255 255 255
>     POSITION LL
>     KEYSIZE 18 12
>     KEYSPACING 5 5
>     TEMPLATE "ttt"
>     LABEL
>       TYPE BITMAP
>       SIZE MEDIUM
>       OFFSET 0 0
>       BUFFER 0
>       MINDISTANCE -1
>       MINFEATURESIZE -1
>       COLOR 0 0 89
>       PARTIALS TRUE
>       FORCE FALSE
>     END
>   END
>   #
>   # Start of scalebar object
>   #
>   SCALEBAR
>     STATUS ON
>     COLOR 255 255 255
>     OUTLINECOLOR 0 0 0
>     BACKGROUNDCOLOR 0 0 0
>     IMAGECOLOR 255 255 255
>     UNITS KILOMETERS
>     INTERVALS 5
>     SIZE 150 5
>     STYLE 0
>     POSITION LL
>     LABEL
>       TYPE BITMAP
>       SIZE SMALL
>       OFFSET 0 0
>       BUFFER 0
>       MINDISTANCE -1
>       MINFEATURESIZE -1
>       COLOR 0 0 0
>       PARTIALS TRUE
>       FORCE FALSE
>     END
>   END
>   #
>   # Start of OutputFormat object
>   #
>   OUTPUTFORMAT
>     NAME "png"
>     MIMETYPE "image/png"
>     DRIVER "GD/PNG"
>     EXTENSION "png"
>     IMAGEMODE PC256
>     TRANSPARENT FALSE
>   END
>   #
>   # Start of layer definitions
>   #
>   LAYER
>     NAME "Roads"
>     STATUS ON
>     DATA "./roads/roads"
>     TYPE LINE
>     UNITS METERS
>     SIZEUNITS PIXELS
>     METADATA
>       "Description"    "Test"
>     END
>     CLASS
>       NAME "Roads"
>       STYLE
>         SYMBOL 0
>         COLOR 220 0 0
>         SIZE 1
>         MINSIZE 1
>         MAXSIZE 100
>       END
>     END
>   END
> 
>   LAYER
>     NAME "Earth Quake Risk 0.05 - 0.10"
>     STATUS ON
>     DATA "./earthQuakeHazard/eqriskdd"
>     TYPE POLYGON
>     UNITS KILOMETERS
>     SIZEUNITS PIXELS
>     METADATA
>       "Description"    "Earth Quake"
>     END
>     CLASS
>       NAME "RISKVAL2"
>       EXPRESSION ('[RISKVAL]' eq '0.05 - 0.10')
>       LABEL
>         TYPE TRUETYPE
>         FONT "fritqat-bold"
>         SIZE 10
>         POSITION LL
>         OFFSET 0 0
>       END
>       STYLE
>         SYMBOL 0
>         COLOR 255 150 123
>         SIZE 1
>         MINSIZE 1
>         MAXSIZE 100
>       END
>     END
> 
>   END
> 
> 
>   LAYER
>     NAME "Earth Quake Risk < 0.05"
>     STATUS ON
>     DATA "./earthQuakeHazard/eqriskdd"
>     TYPE POLYGON
>     UNITS KILOMETERS
>     SIZEUNITS PIXELS
>     METADATA
>       "Description"    "Earth Quake"
>     END
>     CLASS
>       NAME "RISKVAL2"
>       EXPRESSION ('[RISKVAL]' eq '< 0.05')
>       LABEL
>         TYPE TRUETYPE
>         FONT "fritqat-bold"
>         SIZE 10
>         POSITION LL
>         OFFSET 0 0
>       END
>       STYLE
>         SYMBOL 0
>         COLOR 255 255 181
>         SIZE 1
>         MINSIZE 1
>         MAXSIZE 100
>       END
>     END
>   END
> 
>     LAYER
>     NAME "Earth Quake Risk > 0.10"
>     STATUS ON
>     DATA "./earthQuakeHazard/eqriskdd"
>     TYPE POLYGON
>     UNITS KILOMETERS
>     SIZEUNITS PIXELS
>     METADATA
>       "Description"    "Earth Quake"
>     END
>     CLASS
>       NAME "RISKVAL2"
>       EXPRESSION ('[RISKVAL]' eq '> 0.10')
>       LABEL
>         TYPE TRUETYPE
>         FONT "fritqat-bold"
>         SIZE 10
>         POSITION LL
>         OFFSET 0 0
>       END
>       STYLE
>         SYMBOL 0
>         COLOR 247 81 148
>         SIZE 1
>         MINSIZE 1
>         MAXSIZE 100
>       END
>     END
>   END
> 
> 
> 
> # Layer
> END
> 
> 
> 
> 
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> 


Hi!

The layerobject->numclasses gives you the count of classes. With this 
you can loop through and use layer->getClass(int classIndex) to get each 
class and draw the legendicons.

Regards,
Norbert