GPS

[Doug Yanega]

>A colleague working in Papua New Guinea is having great difficulty getting
>GPS fixes under the tropical canopy. Does anyone have experience with novel
>solutions to this problem? - there is no need for sub-metre accuracy - 5-10m
>would be fine.

How is your colleague at landmarks and general sense of direction? I
ask because I've found that sometimes - rarely, in truth, but often
enough to be worth it - if one can find a collecting locality on a
satellite image, then it may be possible to get a good lat/long fix
and altitude using the Google Earth program (freeware!). Out of
dozens of localities I've "proofed" (by checking actual GPS readings
versus the parameters given in GE) they have all come out quite close
in elevation - at least within the usual margin of error one
experiences with a GPS. For backwoods areas like PNG, the satellite
photos are often at lower resolution than US locales, but - as I said
up front - if you're the kind of person who has a good mental map of
a place, sometimes even a low-res photo is enough. I've managed to
get coordinates for a fair number of out-of-the-way localities in
Mexico and Thailand that way, because I have a good visual/spatial
memory. It's been a long, long wait, but with GE, folks like me who
routinely need to georeference legacy material finally have a tool
that is almost ideal (my only real gripe is that GE has a million
different "layers" options, but for some %@&*^! reason they do NOT
include watercourses - not even the Amazon River is marked in any
way!).

GE is, for me, the most addictive piece of software (that is not a
computer game) I've ever seen. It might help your friend, if he has
no other options.

Peace,
--

Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California - Riverside, Riverside, CA 92521-0314
phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
              http://cache.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82