[GRASS-dev] what is the ideal way to store spatial data

Gerald Nelson gnelson at uiuc.edu
Sun Dec 30 11:12:55 EST 2007

Since all spatial data are about describing a specific location on a specific planet, usually earth, it would seem that the best way conceptually to store data is with respect to a single easily defined reference point such as the gravitational center of the planet. Any location could then be measured with three values. x,y like latitude and longitude, and z a distance measure from the reference point along a ray. 

Projections such as utm, etc, are about how to convert the 3-d data described above into 2-d with a minimum of distortion. Given the speed of modern computers this conversion process ought to be increasingly easy to do on the fly, as needed. 

The reason I raise this question is to ask the experts whether it would make sense (for 7.x) to think of a single standard way of storing data in grass and then all operations would do the conversions as necessary? There are (at least) two advantages of this. One is standardization of data storage in a form that is closest to a true representation of the real world. A second is to reduce the potential for confusion/mistakes when data are shared and the metadata are not, or are inadequate. I am continually getting access to data where the units are not clearly defined. But even if they are defined say as some utm coordinate, there must be some error in measurement built in.

Just some thoughts on a Sunday morning.

Gerald Nelson
Professor, Dept. of Agricultural and Consumer Economics
University of Illinois, Urbana-Champaign
office: 217-333-6465 
cell: 217-390-7888
315 Mumford Hall
1301 W. Gregory
Urbana, IL 61801

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