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metapost [2019/06/02 23:35]
brucemutton [Symbol Sizing and Positioning] clarify symbol parameter indicator
metapost [2019/06/04 00:02]
tarquinwj [Magnetic effects]
Line 166: Line 166:
  
 I'm going to suggest that the best values for U: components are between [U/u=1.0] to [U/u=1.2] I'm going to suggest that the best values for U: components are between [U/u=1.0] to [U/u=1.2]
 +
 +An here are some examples with a slightly improved U: variable, with the symbol aligned top-left and oriented 30 degrees, and the output rotated 15, 105, 195, 285 degrees.
 +
 +{{:metapost:symbolparameterindicatorsamples.png?400|}}
 +
 +And one last example, using ''point water'', with the above code added, that demonstrates how align is related to scrap coordinates rather than the output coordinates.
 +
 +{{:metapost:symbolscrapaligntooutputalignexplained.png?400|}}
  
 Bruce Bruce
Line 358: 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: 11 days ago
  • by tarquinwj