How to Construct Railroad Style lines?

[Bob Basques]

Oh, no, now you got me going . . .

You could use the same process of stacking things by using two lines on 
top of one another, place a white line (we use white as a Transparent 
color here by default) on top of a slightly wider line of a different 
color, this will in effect give you two side by side lines (rails), then 
place the "tie" (really wide, scrunched up dashed line) on top to get 
the Railroad Ties to loo right.

Basically display the same line three time, Color for rails, then on top 
of that, a transparent color slightly narrower in width, then the Dashed 
line type on top of that that is wider than the rail line, and you have 
real look Railroad tracks.

bobb

Bill Thoen wrote:
> I see what I did wrong... you need to include an OVERLAYCOLOR parameter 
> in the CLASS object to get this to show the 'tie' symbol (the example on 
> the wiki at  http://mapserver.gis.umn.edu/cgi-bin/wiki.pl?SymbolExamples 
> leaves this out too, and so it doesn't work either).  I tied to fix that 
> but I couldn't get edit access to the wiki  (and BTW, the word 
> "illusive" on that page should probably be "elusive" if anyone's feeling 
> pedantic and is able to make some edits there).
>
> What it does is drop a dashed line over the solid line with the dashed 
> line set to be 3 times thicker than the solid line. Since the dash 
> pattern is 1 pixel followed by 3 empty ones this has the effect of 
> creating a line like a string of square beads (e.g. ---o---o---o---o). 
> It looks okay, but it's not the classic cartographic symbol for railroads.
>
> Has anyone come up with something better?
>
> Bill Thoen wrote:
>   
>> It seems that line styles for railroads (i.e. lines that look like  
>> ---|--|--|--|--) are pretty hard to find in the documentation. I did 
>> find one googlit on the subject from 2003 
>> (http://mapserver.gis.umn.edu/data2/wilma/mapserver-users/0302/msg00716.html) 
>> but I can't seem to make it work. The following map file excerpt built 
>> from that suggestion just seems to produce a simple red line. I don't 
>> see how this makes the "tie" lie crossways to the track line. Does 
>> anyone know what I did wrong? Is there a more modern solution?
>>
>> MAP
>>  ...
>>  SYMBOL
>>      NAME 'line'
>>      TYPE ELLIPSE
>>      FILLED TRUE
>>      POINTS 1 1 END
>>   END
>>   SYMBOL
>>      NAME 'tie'
>>      TYPE ELLIPSE
>>      FILLED TRUE
>>      POINTS 1 1 END
>>      STYLE 1 3 END
>>   END
>> ...
>>  LAYER
>>      NAME railroads
>>      GROUP transportation
>>      TYPE LINE
>>      STATUS ON
>>      CONNECTIONTYPE OGR
>>      CONNECTION "railroads.TAB"
>>      LABELITEM "Name"
>>      CLASS
>>         NAME "Railroads"
>>         COLOR 255 100 100
>>         SYMBOL 'line'
>>         SIZE 1
>>         OVERLAYSYMBOL 'tie'
>>         OVERLAYSIZE 3
>>      END
>>      PROJECTION
>>         "init=epsg:4326"
>>      END
>>   END
>> ...
>> END
>>
>>
>> TIA,
>> - Bill Thoen
>>
>>     
>
>   


-- 

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