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Posted by Bill Blum on August 14, 2004, 1:05 am
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Could someone point me in the right direction for the following problem
that I've run into....
Given two points on the earth, in WGS84 or NAD83 lat/long, I need to be
able to find the following:
- distance between them
- terrain profile between the points
Pointers to journal articles/algorithms/source code would be
appreciated. ( Windows-based applications aren't useful, as I'm using
Macintosh and Sun platforms. )
Thanks!
- Bill Blum
Grad Student, Wright STate University
Replies to group please, email address goes nowhere.
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Posted by Dave Patton on August 14, 2004, 2:23 am
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> Could someone point me in the right direction for the following problem
> that I've run into....
>
> Given two points on the earth, in WGS84 or NAD83 lat/long, I need to be
> able to find the following:
> - distance between them
> - terrain profile between the points
http://williams.best.vwh.net/avform.htm
http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
For the terrain profile you would have to have
information about the terrain, presumably a
Digital Elevation Model(DEM). The availabilty
of DEMs vary throughout the world, so a lot will
depend on where the points are, and what sort
of results are required.
--
Dave Patton
Canadian Coordinator, Degree Confluence Project
http://www.confluence.org/
My website: http://members.shaw.ca/davepatton/
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Posted by Bill Blum on August 14, 2004, 2:34 pm
Please log in for more thread options Dave Patton wrote:
> For the terrain profile you would have to have
> information about the terrain, presumably a
> Digital Elevation Model(DEM). The availabilty
> of DEMs vary throughout the world, so a lot will
> depend on where the points are, and what sort
> of results are required.
>
I've got access to DTEDs for everywhere I need, so that's not an issue.
Thanks for the pointer to the Vincenty article.
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Posted by Paul Hirose on August 14, 2004, 5:26 pm
Please log in for more thread options I can't help regarding the terrain profile between points, but the
newsgroup FAQ discusses various ways of calculating the distance:
http://www.census.gov/cgi-bin/geo/gisfaq?Q5.1
--
To reply by email delete INVALID from address.
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Posted by Ron McConnell on August 17, 2004, 4:26 am
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Hi, Bill,
I see you have already been directed to the US NGS versions
of Vincenty's inverse and direct/forward algorithms.
Note that there are 3D versions if one has the elevation data
as you do.
FYI, also:
Vincenty Inverse and Direct formulas, Chapter 4 of
Geocentric Datum of Australia, Technical Manual
<http://www.icsm.gov.au/icsm/gda/gdatm/gdav2.2.pdf>
Also Excel spreadsheet = vincenty.xls
My freeware GCB program (executable and source) at my web site
includes Sodano's inverse in addition to Vincenty's.
Cheers,
Ron McC.
w2iol@arrl.net
Ronald C. McConnell, PhD
WGS-84: N 40º 46' 57.6" +/-0.1"
W 74º 41' 22.1" +/-0.1"
FN20ps.77GU31 +/-
V +5058.344 H +1504.253
http://home.earthlink.net/~rcmcc
Old dogs can learn new tricks.
They just have trouble unlearning old ones.
- Bob Welborn
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