[postgis-users] Massive Lidar Dataset Datatype Suggestions?

[Robert W. Burgholzer]

Perhaps I've weighed in on this before, so excuse me if I sound like a 
broken record. This situation appears to me to be best suited to a raster 
analysis. I would like to see (help to develop) this type of functionality 
in postgis.

 From what I have seen, there are no raster components to the OGC specs for 
SQL. IMHO, this is a logical next step, and also one that could be 
potentially very powerful for the integration of environmental data such as 
the lidar elevations and so forth. Of course, with anything worthwhile, 
this will require some time and expertise - something I am more than 
willing to be involved in. If anyone could comment on some documents that 
might point one to how to outline a raster specification for SQL, that 
would be great.

A potential set of components:
- Raster as rectangular feature
- Geometry column holds boundaries of raster rectangle
- raster data as file pointer or large data object (BLOB?)


Rob

At 12:34 PM 11/13/2004 -0800, you wrote:
>Greetings all,
>
>I asked some questions about massive point datasets in April, before the 
>implementation of LWGEOM. Then I fell off the face of the earth for a 
>while.  Know I'm back working on this issue again and would love some input.
>
>I have a LIDAR dataset of 473 million points with 2 point geometries 
>(first & last returns), timestamp and 2 laser intensity returns (integer).
>
>I am trying to figure the best setup for storing, extracting and 
>processing this dataset.  btw, it is a smallish dataset. We will be 
>processing 2 billion+ point projects in the near future.
>
>Currently I compiled & installed postgresql 8.0 beta 4, with postgis 0.9 
>release, geos 2.0.1, and proj 4.  This is on Fedora Core 2, smp 733mhz, 
>1GB ram, 160gb hdd Intellistation.
>
>I am using HWGEOM, with WKT right now and managed to create a table 
>with  oid & the_geom for one point per return.
>The upload took 48 hours and is roughly 85GB.
>The GiST indexing took ~80 hours and is ~35GB.
>
>This is obviously non-optimal considering we now have WKB and LWGEOM to 
>play with.  I couldn't get LWGEOM to install properly from the cvs 
>extract, which is why I reverted to the 0.9 version.
>
>So, any suggestions on how to get the full 9-column dataset uploaded with 
>a more efficient data structure?  (note: current machine is just a test 
>machine. Production will have a LOT more drivespace).
>
>Also, I intend to perform a fair amount of point processing inside the 
>database using either plpgsql or java api.  Is this a bad idea?
>
>Thanks for any input.
>
>________________
>Collin Bode
>GIS Informatics Researcher
>Power Lab, Integrative Biology
>University of California, Berkeley
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Robert Burgholzer
Environmental Engineer
MapTech Inc.
phone: 804-869-3066
http://www.maptech-inc.com/