[GLIMS] Merge of RGI into GLIMS has begun

[Bruce RAUP]

Hi all,

I've begun to merge the Randolph Glacier Inventory (RGI) into the GLIMS
Glacier Database.  I have just ingested the RGI New Zealand glacier
outlines.  The main tasks for doing this merge include:

- "flattening" the shapefiles (changing "holes" to nunatak polygons) to
   conform to the GLIMS data model.

- changing the GLIMS IDs in the RGI data set to those already assigned to
   outlines in GLIMS, so that each glacier has outlines tagged with the same
   glacier ID.  Otherwise, double-counting and other horrible things happen.

- finding and assigning appropriate metadata about analyst(s), as-of
   date(s) for the outlines, imagery, etc.  This is probably the most
   difficult part, and I'll need the aid of the community in many cases.

I want to give a heads-up to the GLIMS community early in the process and
solicit comments so that any concerns can be dealt with before much data is
ingested.

In particular, to the RGI community:  GLIMS IDs that you've assigned to
glaciers that already were represented in the GLIMS database will change.
We should figure out how to flow this information back into the RGI.

Note that after an ingest has taken place, we can still update the metadata
when needed.  For example, if we learn of the involvement of an additional
analyst, or more detail about the mapping process, we can add that
information to the database.

I am also working on two output options for GLIMS:

1. a way to get the "latest snapshot" of the database.  That is, a way to
download one outline for each glacier, taking only the most recent one in
each case;

2. a way to download GLIMS data with all nunatak polygons converted to
"holes" in the glacier boundary polygon.

I'm not sure when these will be ready, but they are in the works.

I welcome all comments and suggestions.  Note that I'll be in Nepal for the
next 2.5 weeks, and next week I will be unplugged from the Internet.  I'll
be at AGU after that, Tuesday-Friday, where I hope to have a nice poster on
this topic.

Cheers,
Bruce