Subject: RE: Coordinate systems

Selecting a Coordinate System

Subject:      RE: Coordinate systems

Author:       Jesse Yoder jesse@flowresearch.com

Date:         Sun, 8 Feb 1998 12:06:58 -0500

John Conway wrote -

>"People studying such subjects as potential theory,

fluid dynamics and the like use all sorts of non-linear coordinate

systems determined by the particular shapes that concern them.  So

for instance you'd use spherical polar coordinates (r,theta,phi) for

a problem involving spheres, cylindrical polars (r,theta,z) for one

involving cylinders, ellipsoidal coordinates (often called "confocal"

coordinates" for one involving ellipsoids, and so on."

RESPONSE: I find your comments on fluid dynamics very interesting, since

I claim that Circular Geometry has implications for the measurement of

fluid flow in pipes. So what you are saying, then, is that engineers

measuring circular pipes use coordinate systems that are appropriate for

the particular circular shapes they are measuring. I find this very

encouraging to hear.

I also find it interesting to hear you say this, since you have

indicated that you don't find the idea of selecting a Point size to suit

a particular measurement to be a worthwhile concept -- yet you claim

that other people already do something even more extreme -- select a

different coordinate system to suit a particular measurement. So

according to you, it's just fine to shift coordinate systems to make a

particular measurement, which is implied by what I have been saying all

along.

Jesse Yoder

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