A Detail On Using A Plane Table

The lines do not have to all
cross at the same place

file: mapCT.htm

This page discusses a detail of using a plane table, which you might be doing if you were "playing at" making maps.

For the purposes of this page, I set up a rather artificial scenario... but it absolutely has firm parallels with "normal" plane table use.

I put the plane table a few feet in front of a plain wall, and put some labels... "X", "A", "B", "C", "D" and "E".. on the wall.

The premise I am working to is that you want to know the following angles, all named as if the plane table were at "Y"...

     XYA
     XYB
     XYC
     XYD
     XYE

View from above. The ruler you can see on the plane table is the sight tool for lining up on a target to draw the line for that target...

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View from surveyor's position. Arrows indicate the "sights" with which the strip of wood can be lined up on target. Currently shown pointing towards target "X"...

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NOTE: Lines do not need to... indeed probably shouldn't... all cross the line towards "X" at the same place.

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Valid HTML 4.01 Transitional Page tested for compliance with INDUSTRY (not MS-only) standards, using the free, publicly accessible validator at validator.w3.org. Mostly passes.

...and passes... Valid CSS!

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