[postgis-users] lidar: what is the recommended wayof storing/indexing

[Paul Ramsey]

Generally (raw) LIDAR data is not on a regular grid, it's irregular.
So it's not a raster problem it's a billions-of-points problem, and
not just a billions-of-points problem, but a
billions-of-hyper-dimensional-points problem (though the indexing can
be in just 2- or 3-d, really). So grid-based solutions aren't really
going to do it.

P.

On Thu, Jul 8, 2010 at 9:22 AM, Paragon Corporation <lr at pcorp.us> wrote:
> Okay since everyone is providing their suggestions, let me provide my less
> than educated suggestion based on my fuzzy assumption of how Lidar is
> structured.
>
> Why don't you just use the new WKT Raster (PostGIS raster storage)?  It
> allows you to store multiple bands per pixel.  I think you might even be
> able to use GDAL to load the Lidar data right in ot the PostGIS raster
> storage format given this bug fix.
>
> http://trac.osgeo.org/gdal/ticket/3523
>
> So I'm  imaging your z, range, target number, reflectance you would store as
> separate raster bands.
>
> Pierre and Jorge can correct me, but I don't think there is a limit on the
> number of raster bands you can store per raster tile
>
> http://www.postgis.org/documentation/manual-svn/RT_reference.html
>
> With that you can do spatial intersects queries to pull out the different
> band values with
>
> http://www.postgis.org/documentation/manual-svn/RT_ST_Intersection.html
>
> or
>
> http://www.postgis.org/documentation/manual-svn/RT_ST_Value.html
>
> The meta data function would be useful for letting you know how many bands
> you have etc.
>
> http://www.postgis.org/documentation/manual-svn/RT_ST_MetaData.html
>
> Hope that helps,
> Regina
> ________________________________
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Peter
> Baumann
> Sent: Thursday, July 08, 2010 9:32 AM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] lidar: what is the recommended wayof
> storing/indexing
>
> Indeed, a column store for arrays is usually quite ;-) inefficient.
> Let me point you to the rasdaman array DBMS which plugs into PostgreSQL and
> offers an optimized array query language on top. See www.rasdaman.org.
>
> -Peter
>
>
>
>
> Paul Ramsey wrote:
>
> Oh, actually one-row-per-point is a bad idea, because the size of
> lidar sets mitigates against that. Putting them into multipoint
> collections of 50 or 100 points is better. But that implies
> preprocessing things a bit to find good patches. In generally, there's
> a lot of tooling needed to do this well, I fear.
>
> P
>
> On Thu, Jul 8, 2010 at 6:27 AM, Paul Ramsey <pramsey at opengeo.org> wrote:
>
>
> There is no recommended way right now. It's a core development
> activity I'd love to have funded... :)
>
> http://opengeo.org/products/coredevelopment/postgis/pointclouds/
>
> In the meanwhile a approach might be to put the x/y/z into a postgis
> geometry and stuff the rest of the data into an array of doubles in
> another column. Your app would need to know which array element was
> which kind of data, but you'd still have it all available.
>
> P.
>
> On Thu, Jul 8, 2010 at 2:53 AM, Biddy <newskatze at riomhphost.net> wrote:
>
>
> Hi everyone,
>
> is there a recommended way of storing lidar data in postgis?
>
> In particular, I am interested in not just storing long, lat, alt but also
> keeping all the raw data (for example range, target number, reflectance,
> etc.)
>
> Regards,
> B.
>
>
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> --
> Dr. Peter Baumann
>  - Professor of Computer Science, Jacobs University Bremen
>    www.faculty.jacobs-university.de/pbaumann
>    mail: p.baumann at jacobs-university.de
>    tel: +49-421-200-3178, fax: +49-421-200-493178
>  - Executive Director, rasdaman GmbH Bremen (HRB 147737)
>    www.rasdaman.com, mail: baumann at rasdaman.com
>    tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
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> ventis dimissa, sed Deo commendata, precamur ut ei reddatur cui soli
> destinata, nec preripiat quisquam non sibi parata." (mail disclaimer, AD
> 10xx)
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