Proposal for RC --> NSIDC data transfer methodology: Rev. 1.11

[Luke Copland]

A couple of quick responses to Bruce's questions...

> The Point_Measurements table can hold small datasets.  We've talked a bit
> about how (and whether) to handle large elevation grids, but haven't come
> to a conclusion.  GeoTIFF files would probably work for that.  I wonder
> what the volume of such data would be.

...geotiff files seem to be pretty efficient at handling datasets. A DEM
of the entire Devon Island Ice Cap and surrounding areas (approx. 250 x
150 km) at 100 m spacing is ~10 Mb in size. A DEM produced from a full
ASTER scene by the EROS Data Center is ~15 Mb in size.

> > We're tending towards the idea of working upwards from a glacier
> > terminus, and counting all tributaries that feed ice and water into the
> > terminus as part of one single glacier.
> 
> Sounds reasonable.  Does ArcView do this delineation for you automatically?
> Or have you written Avenue scripts to do it?
...the Basin extension in ArcView does this delineation automatically
from a DEM, and can be downloaded from www.esri.com. The hydrologic
modelling extension also needs to be loaded to provide the inputs for
the basin extension - the hydrologic modelling extension is provided
with ArcView in the examples directory.

> 
> > I'm currently working on defining and cataloguing the glaciers on Manson
> > Ice Cap, Ellesmere Island, as a way to work through potential problems
> > and to demonstrate our methods to others. Once done, I'll send on the
> > information to NSIDC so that it can be input to the database and any
> > issues can be identified.
> 
> This is exactly what we were hoping for!  We would appreciate other groups
> who are at a similar stage to do likewise.
> 
> Siri Jodha and I just chatted and realized we interpreted your last
> sentence slightly differently.  By "issues", do you mean with the data
> transfer method?  Or were you talking about issues with the definition of
> "glacier"?  (I assume you meant the former.)
...I guess I mean with both! It will provide an opportunity to see
whether others agree with our definition of glaciers, and will also
provide a test for the database. I'm away Oct. 11 to Nov. 12, so am not
sure if I'll get the whole ice cap done before I leave. However, I can
try and send NSIDC the information for just a couple of glaciers/basins
before I go as an initial test.

Cheers,
Luke.

-- 
Dr. Luke Copland
Department of Earth & Atmospheric Sciences
University of Alberta
Edmonton, Alberta T6G 2E3, Canada

Tel: 780 707 5583, Fax: 780 492 7598
luke.copland at ualberta.ca, http://arctic.eas.ualberta.ca/luke