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Accumulo, mail # dev - accumulo geo


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accumulo geo
Anthony Fox 2011-10-26, 20:30
All,

I would like to gauge the interest in an extension to Accumulo to enable
geospatial capabilities.  Currently, I have developed a schema for storing
raster data as tiles in Accumulo and a plugin to Geoserver that allows
Accumulo tables that use the specified schema to be exposed as WMS layers
for importing into a GIS.  This is a natural fit for Accumulo since the
individual tiles are not large but the aggregate set of tiles that make up
a single layer can become very large.  Accumulo packages those tiles into
blocks and distributes them around the cloud for quick access and redundant
storage.  The implementation is in an early state.

I am currently investigating the feasibility of implementing an API for
storing, querying, and processing vector data in Accumulo.  I would like
the API to be able to answer nearest neighbor queries, perform on-the-fly
reprojections for queries that come in in a particular projection, various
standard geospatial transformations such as buffering and finding
intersections, etc.  My current thought is that the approach would be
similar to how PostGIS extends Postgres in that it dictates a schema and
storage format and then provides a user level api (a bunch of sql
functions) for processing that data.  PostGIS also provides an r-tree index
implemented on top of GiST to enable geospatial querying.  This type of
functionality is also a natural fit for Accumulo as r-tree minimum bounding
rectangles can map to tablet extents.  However, this change would require
modifications to core functionality.  Some mechanism for hooking in
alternative 'extents' may be a technique for dealing with this kind of
indexing scheme.

Is there any interest in these kinds of geospatial processing capabilities
in the Accumulo community and has anyone thought about/implemented some
geospatial functions?

Thanks,
Anthony