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metapost [2019/06/03 01:04]
brucemutton [Symbol Sizing and Positioning] explain align in scrap versus output
metapost [2019/06/04 00:02]
tarquinwj [Magnetic effects]
Line 366: Line 366:
  
   text en "point u:​warning"​ "​warning/​danger"​   text en "point u:​warning"​ "​warning/​danger"​
-      ​+ 
 +===Magnetic effects=== 
 + 
 +Certain rocks can cause a compass to give the wrong reading. This icon can be used to show areas where this happens (ie. where the survey may be unreliable as a result); a spinning compass: 
 + 
 +<​code>​ 
 +code metapost 
 +  % a spinning compass 
 +  def p_u_magnetism (expr P,R,S,A)= 
 +    scale:​=0.5u;​ 
 +    halfline:​=(0.5u/​20S);​ %half thickness of PenC - pen thicknesses do not scale with S 
 +    pointheight:​=scale*.9;​ 
 +    pointwidth:​=scale*.4;​ 
 +    U:​=(scale,​scale);​ 
 +    T:=identity aligned A rotated (R-20) scaled S shifted P; 
 +    % a circle 
 +    thdraw fullcircle scaled 2scale withpen PenC withcolor black; 
 +    % filled triangle 
 +    thfill (0,​pointheight)--(pointwidth,​0)--(-pointwidth,​0)--cycle withcolor black; 
 +    % black triangle outline 
 +    thdraw (0,​-pointheight+halfline)--(pointwidth-halfline,​0) withpen PenC withcolor black; 
 +    thdraw (0,​-pointheight+halfline)--(-pointwidth+halfline,​0) withpen PenC withcolor black; 
 +    % spin arcs, a full circle is path 0-8, anticlockwise,​ starting from the right 
 +    thdraw subpath (2.4,3.5) of fullcircle scaled 1.5scale withpen PenC withcolor black; 
 +    thdraw subpath (6.4,7.5) of fullcircle scaled 1.5scale withpen PenC withcolor black; 
 +  enddef; 
 +  initsymbol("​p_u_magnetism"​);​ 
 +endcode 
 +</​code>​ 
 + 
 +{{ ::​magnetism.png?​nolink |}} 
 + 
 +Select this as point type "​u"​ with "​-subtype magnetism"​ in its options. Use it with this line in your layout: 
 + 
 +  text en "point u:​magnetism"​ "​magnetism"​
 ====Line Symbols==== ====Line Symbols====
 ===View whole centerline for underground=== ===View whole centerline for underground===
  • metapost.txt
  • Last modified: 3 days ago
  • by tarquinwj