[postgis-devel] Cubic splines in GML

[Andrei Ionita]

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Hi everyone,

I am seeking help on understanding the concept that GML is defining for
cubic splines. I am involved in writing an interpolation algorithm in
the deegree software that returns points on a cubic spline.

Firstly, I have been looking at the GML definition of cubic splines and
wondering how to interpret it. There, a cubic spline consist of control
points and starting and ending tangent vectors. It appears as the
piecewise cubic polynomials (that are defined mathematically for a cubic
spline) can be deduced from the two tangents, but how does one do that?

Or is the target of the GML type not one of defining a rigorous math object?

Apart from that however, I would also like to ask if someone from
PostGIS has stumbled upon a discrete algorithm for interpolating cubic
splines, or at least can give me some literature references.

Thanks for your attention. Any answers related to this subject will
surely be of help.

Regards,
Andrei
- --
Andrei Ionita

l a t / l o n  GmbH
Aennchenstrasse 19               53177 Bonn, Germany
phone ++49 +228 18496-0          fax ++49 +228 18496-29
http://www.lat-lon.de            http://www.deegree.org

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