[Merkaartor] Drawing buildings

Boris Cornet borisC at osm-at.org
Wed Sep 8 23:55:57 BST 2010


Hi!

Today (Thursday, September 9, 2010) at 00:08 Chris Browet typed:

> Now that I get the general idea, question is how to calculate 1) and 2)...

> I understand 1) and 2) as the nodes so that one of its adjacent
> segment is parallel and has the same length as its opposite side, right?

Not quite so. Both positions form a right angle at the red node.
1) forms a right angle at the lower left node, while 2) forms a right
angle at the upper right node. The length of both sides will have to
be calculated.

>   How do you calculate the length of the [other] moving sides?
Whew! To much for me at this time of the day, but I guess this is just
a matter of using Pytagoras.

> Would that be supposed to work for polygon with a number of sides
> != 4 or just for rectangular areas?

The method will obviously not work for a triangle, but apart from that
the number of polygon sides is irrelevant since only the two adjacent
sides are involved.

--
Good night,
   Boris




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