Generation of glacier IDs for GLIMS: perl code

[Greg Scharfen]

Bruce --

I also prefer the familiarity of east and west longitudes, so this
revision looks good to me, Greg

_____________________________

On Wed, 12 Jun 2002, Bruce Raup wrote:

> Hi all,
>
> In addition to messages pointing out my north-south mistake, I got some
> feedback (much of it from Hugh Kieffer) on GLIMS glacier IDs:
>
> 1.  It was thought that having a flexible number of digits to the right of
> the implied decimal place could lead to confusion.  Thus, leaving it at 3
> digits was recommended.
>
> 2.  It was pointed out that the underscore is unneeded.
>
> 3.  There was a preference for having the E/W, N/S designators *follow*
> their corresponding numbers.
>
> 4.  The original specification called for only east longitudes, in the
> range of [0,360).  Luke Copland stated that using west longitudes for his
> area was easier.  If we allow W or E longitudes to be used, then we must
> allow longitudes only in the range (-180,180].  Otherwise, we could get
> two IDs in the western hemisphere that point to the same place on the
> ground, but that would be distinct IDs (e.g. G050000W040000N and
> G310000E040000N).
>
> Reminder:  the rationale for having the lon/lat encoded in the glacier ID
> is so that Regional Centers can generate unique IDs without having to
> consult with anyone else (like, e.g. querying the database for the next
> available ID).
>
> So, I propose an ID format as follows:
>
>   Gdddddd[W|E]ddddd[N|S]
>
> There are 3 digits to the right of the implied decimal place.  [W|E] means
> either W or E.  Longitudes must be in the range [0,180], with W or E
> designating hemisphere.  Latitudes range [0,90].  As an example, if there
> were a glacier where NSIDC is, it would have the ID "G105253W040013N".
>
> IS THIS OKAY WITH EVERYONE?
>
> Thanks,
> Bruce
>
> --
> Bruce Raup
> National Snow and Ice Data Center                     Phone:  303-492-8814
> University of Colorado, 449 UCB                       Fax:    303-492-2468
> Boulder, CO  80309-0449                                    braup at nsidc.org
>
>
>
>