[postgis-devel] GSoC PostGIS Raster Ideas, Implement a set of geometry to raster functions

[dustymugs]

That's a good question. There aren't many generic interpolation methods
that are simple to apply to an arbitrary dataset. The most generic
(inverse distance weighting) has already been implemented. The next most
generic (kriging) could be implemented but I don't see a solid reason as
that capability and much more is accessible using PL/R.

So, interpolation should be specific to a purpose/context. I have been
thinking that we may end up with specific extensions, e.g.
postgis_lidar, postgis_elevation, postgis_hydrology.

-bborie

On 04/17/2013 10:12 AM, Pierre Racine wrote:
> So what interpolation capabilities should we provide?
> 
> Something specific for lidar and something else specific for distribution of a species? In other word, only specialized interpolation methods? No generic ones?
> 
> Pierre
> 
>> -----Original Message-----
>> From: postgis-devel-bounces at lists.osgeo.org [mailto:postgis-devel-
>> bounces at lists.osgeo.org] On Behalf Of Bborie Park
>> Sent: Wednesday, April 17, 2013 11:58 AM
>> To: PostGIS Development Discussion
>> Subject: Re: [postgis-devel] GSoC PostGIS Raster Ideas, Implement a set of
>> geometry to raster functions
>>
>> I won't say I am against providing interpolation capabilities.  What I
>> will say is that I am absolutely against providing generic
>> interpolation capabilities applicable to everything.  The
>> interpolation and prior knowledge needed to generate a raster from a
>> LIDAR point cloud is very different than that needed to estimate the
>> distribution of a species.
>>
>> -bborie
>>
>>
>> On Wed, Apr 17, 2013 at 7:52 AM, Pierre Racine
>> <Pierre.Racine at sbf.ulaval.ca> wrote:
>>> Hi Ivan,
>>>
>>> Basically we need to be able to interpolate from very few points or from
>> millions of them. Those points have to be stored as PostGIS GEOMETRY and
>> we want to be able to produce only one raster (passing the georeference
>> metadata similar to what we pass to ST_AsRaster) or a tiled raster coverage
>> based on an already one.
>>>
>>> Could you speak more about the approach you would use to interpolate
>> millions of points into a tiled raster coverage based on another one, which
>> would be, for me, the most difficult case?
>>>
>>> Are you aware and do you understand Martin Isenberg approach for
>> "Generating Raster DEM from Mass Points via TIN Streaming"
>> (http://www.cs.unc.edu/~isenburg/)?
>>>
>>> Bborie also has a strong opinion about (against) interpolation. Maybe we
>> would like to hear about its point of view?
>>>
>>> Pierre
>>>
>>>> -----Original Message-----
>>>> From: postgis-devel-bounces at lists.osgeo.org [mailto:postgis-devel-
>>>> bounces at lists.osgeo.org] On Behalf Of Ivan Alargic
>>>> Sent: Wednesday, April 17, 2013 10:12 AM
>>>> To: postgis-devel at lists.osgeo.org
>>>> Subject: [postgis-devel] GSoC PostGIS Raster Ideas, Implement a set of
>>>> geometry to raster functions
>>>>
>>>> Hi all,
>>>>
>>>> Can someone tell me if the idea about implementation of geometry to
>>>> raster functions is still available for GSoC 2013?
>>>>
>>>> I am particularly interested in the implementation of ST_Interpolate
>>>> function but I would be also ready to implement other geometry to
>> raster
>>>> functions if it would be required.
>>>>
>>>> This topic is interesting to me because it is related to my research about
>>>> storing and processing of LiDAR data in PostGIS. Moreover, I posses
>>>> experience with Triangle library, which I used to generate terrain models
>>>> from LiDAR data and interpolate elevation.
>>>>
>>>> Regards,
>>>>
>>>> Ivan Alargic
>>>> University of Novi Sad, Serbia
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