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From: yuleat@prlhp1.prl.philips.co.uk (yuleat)
Newsgroups: comp.graphics
Subject: Contour to grid algorithm
Message-ID: <661@prlhp1.prl.philips.co.uk>
Date: 25 Oct 88 09:47:03 GMT
Reply-To: yuleat@prlhp1.UUCP ()
Organization: Philips Research Laboratories, Redhill, UK
Lines: 26

Can anyone help me with the following problem?

I have data for a relief map in terms of height contours.
The data stored for each contour is :
    1. A height above sea-level
    2. A linked list of points, which are joined by
       straight line segments to make up the contour.

The area mapped by this data is rectangular and all component
points of the contour must be within this area.  As a result,
some contours do not join up, as they start/finish off the map.
All the contour line segments are guarenteed not to touch/cross.

The problem I have is that I wish to convert this relief data
stored in contour form into a form where a uniform rectangular
grid is used.  Each point of the grid will have a spot height.

I have considered a number of "simple" algorithms, but they
all tend to fail in particular cases (mostly near the corners
of the rectangular map area, when contours are sparse).

How do I work out what the height should be at each point?

                Thanks in advance,

        Andy Yule (yule@prl.philips.co.uk)