making efficient map layers

[Jeff Portwine]

When I use a class definition like this, I only get the 1 pixel line, I
don't see it overlayed on the wider line.

    CLASS
      maxscale 99000
      STYLE
        SYMBOL 0
        SIZE 3
        COLOR 0 255 0
      END
      STYLE
        SYMBOL 0
        SIZE 1
        COLOR 255 255 255
      END
    END

This class only draws the white line and ignores the green style... I'm not
sure why.

-Jeff

>> - How do you go about changing the width of the different types of
>> roads?  I assume each class of road is in a different layer and you
>> somehow manipulate the line width?
>
> In your class for the roads do something like this:
>
> CLASS
>   EXPRESSION ...
>   STYLE  # first draw a 5 pixel wide green line
>     SYMBOL 0 # built in circle symbol
>     SIZE 5
>     COLOR 0 255 0  # green
>   END
>   STYLE  # then draw a 3 pixel wide white line on top of the green
>     SYMBOL 0   # that leaves a 1 pixel border on each side of the white
>     SIZE 3
>     COLOR 255 255 255  # white
>   END
>   STYLE  # then draw a 1 pixel wide black line down the center
>     SYMBOL 0
>     SIZE 1
>     COLOR 0 0 0  # black
>   END
>   ...
> END
>