Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
 
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: converting a paper contour map to a digital 3D image

Tony

I believe that the process you describe is the same as making a digital terrain model from contour data. This is a fairly standard operation in the world of Geographic Information Systems. Unfortunately, the choice of software for doing this on a Mac is limited.

The first step is to scan the contours. Often, if there is accessory data on the paper map, it is most efficient to trace the contours first to avoid having to edit out the noise in the digital raster domain. The contours then need to be vectorized. On the Mac there are several choices of graphics software to "trace" raster linework to create a vector coverage (e.g. Adobe Streamline, Canvas).

The next step is to label the contour lines with the appropriate attribute data e.g. elevation. Then a raster grid is interpolated between the contour lines, to give the regular x,y,z data you are after. This is a job for GIS. This is where the choice really becomes limited. The best tools for this both run on OSX under X-Windows: GRASS (open source), and TNTmips (expensive). I used to use Spyglass Transform (now sold by Research Systems as Noesys), for the grid interpolation too (but only under OS 9).

While I would prefer to use a Mac for all this, GIS is one area where there are better tools for Windows. I have used ArcVIew running on VirtualPC for some of these tasks, and there are specialized PC tools like R2V for vectorizing scanned maps, and ANUDEM (written by Mike Hutchinson in the Maths Dept. at ANU) for making DEMs from contour data.

If what you want to do is just create a set of x,y,z points along a contour, rather than an interpolated grid, then the best tools I know are in specialized GIS software, including ArcScan (part of ArcGIS) and R2V (expensive commercial WIndows software). These tools will follow or trace any single raster contour line from a scan, and with ArcGIS, you can output the location of nodes along the vectorized line. You may be able to do this in GRASS on the Mac, though I haven't tried it.

Brian
___________________________________
Brian Slater
Assistant Professor, Soil Science
School of Natural Resources
The Ohio State University
2021 Coffey Road
Columbus OH 43210
614-292-5891


On Wednesday, June 11, 2003, at 01:08 AM, email@hidden wrote:

Hi all,

I asked about this sometime ago but did not get a reply.

perhaps it is too difficult to do.

What I was after was a way to take a contour plot of a terrain (or any thing fro that matter) and convert the contour intervals and positions into a digital x,y, z type data set for use in a 3D visualization program.

Any ideas?

Something along the lines of data thief or its successors would be ideal. ie be able to follow a selected contour and generate a set of xy points that related to it.

I suspect that it would be tough to do something like that in a completely automatic sense but maybe...

Any help would be appreciated.

Thanks very much.

tony
_______________________________________________________
Dr. Anthony P. Scott,
Computational Quantum Chemistry Gp,	Office Ph.: 	61-2-6125-3573
Research School of Chemistry,		Dept. Ph.:  	61-2-6125-3637
Australian National University,			Fax: 			61-2-6125-0750
Canberra, ACT 0200,				
AUSTRALIA.

E-mail: email@hidden
_______________________________________________________
_______________________________________________
scitech mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/scitech
Do not post admin requests to the list. They will be ignored. 
_______________________________________________
scitech mailing list | email@hidden
Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/scitech
Do not post admin requests to the list. They will be ignored.
References: 
 >converting a paper contour map to a digital 3D image (From: email@hidden)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2007 Apple Inc. All rights reserved.