Interesting. I came across this paper detailing the design of opentopography.org's lidar system, and they indicate they are doing something akin to load the LAS data in, and then running a spatial index (I'm too early in this game to know the difference between what they are describing and how the GIST index works): http://www.springerlink.com/content/x5q937840983un76/fulltext.pdf
Once I build an index for this 3-d data, setting aside the file size issues, should the spatial querying be relatively efficient? If so, how would I go about doing a cross-tile query? Howard, I am interested in checking out your tools but I don't have access to Oracle, just open source databases. Can I use postgresql to utilize your algorithms? Thanks! --j On Fri, Jun 24, 2011 at 12:39 PM, Shaun Langley <[email protected]> wrote: > Hi Howard, > > I think this is an excellent question! I'm actually in the process of > developing a manuscript that outlines the different methods for storage and > querying of spatial data such as LIDAR. In my situation, I'm leaning towards > using triggers to create dynamic views that would allow me to simultaneously > query all tables of a given type. I intent to explore a variety of different > storage types though... I would love to hear about what you decide to do! > Keep in touch! > > Cheers, > Shaun > > On Jun 24, 2011, at 2:46 PM, Jonathan Greenberg wrote: > >> Folks: >> >> This topic I believe has been brought up before, but I thought I'd >> send an email since I'm a bit of a noob with POSTGIS. We have a large >> collection of Lidar points that I would like to perform spatial >> querying on (e.g. give me all points within a certain bounding box). >> The data (currently in LAS format, but easily loadable into the DB), >> is tiled up into smaller subsets. The data is x,y,z,intensity (and >> some other attributes that aren't so important) I have a few >> questions: >> >> 1) Should I load ALL of the LAS files into one massive table for >> querying (this is going to be a LOT of points). >> 2) If not, is there a trick where if I load up each LAS file into a >> separate table (which would, in theory be preferable since I'd like to >> do some testing before dealing with a database of this size), but >> somehow when I do a spatial query, the query can span multiple tables >> (e.g. say the query box is at the intersection of two adjacent tiles)? >> >> Related: what is the most efficient way to do a spatial query that >> effectively "rasterizes" this data, e.g. the min z value between x1 >> and x2, and y1 and y2, where x2-x1 and y2-y1 are the x and y pixel >> sizes? I'm not talking about interpolation, I'm talking an exact >> query. >> >> Thanks! >> >> --j >> >> -- >> Jonathan A. Greenberg, PhD >> Assistant Project Scientist >> Center for Spatial Technologies and Remote Sensing (CSTARS) >> Department of Land, Air and Water Resources >> University of California, Davis >> One Shields Avenue >> Davis, CA 95616 >> Phone: 415-763-5476 >> AIM: jgrn307, MSN: [email protected], Gchat: jgrn307 >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users > > -------------------------- > Shaun Langley > Graduate Student, PhD > Department of Geography > Michigan State University > Home: (517) 974-9346 > > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
