[pdal] [EXTERNAL] Re: PDAL and OpenLayers

Thu Dec 26 06:26:55 PST 2013

Thanks Michael!
I didn't even know this existed! Awesome. So, back to the original
question, it should be therefore possible to put together a simple
OpenLayers hillshade or colormap visualizer for a pgPointCloud database
using the chain you suggest and display directly in OpenLayers. Then you
wouldn't even need GeoServer. It might be kind of slow however.

The way I would do this is:

In OpenLayers, set up a WMS layer that calls a special tile URL handler on
your server.

On the server, respond to the tile request by outputting the tile area from
a pgPointCloud database directly into a DEM using pdal pipeline
mypipelinefile.xml
then do the rest as you suggest.
gdal_translate -a_srs epsg:3857 points2grid.asc points2grid.tif
gdaldem hillshade points2grid.tif points2grid_hs.tif -z 5 -az 90

Return the tile response to OpenLayers as a jpeg or png.

Roger

On Thu, Dec 26, 2013 at 1:28 PM, Smith, Michael ERDC-RDE-CRREL-NH <
Michael.Smith at erdc.dren.mil> wrote:

>  Roger and Eran,
>
>  To create a DEM from Pointcloud data using PDAL, you can use the
> Points2Grid driver. Here’s an example pipeline. You might also want add a
> filter to select just the last return or the Bare Earth classification if
> your data is classified.
>
>  For pdal, first create an ascii grid file from
> (las/pgpointcloud/whatever) using pdal. Then convert to tif via
> gdal_translate. Then use gdaldem to create the hillshade and color-relief
> images.
>
>  pdal pipeline point2gridpipe.xml
> gdal_translate -a_srs epsg:3857 points2grid.asc points2grid.tif
>  gdaldem hillshade points2grid.tif points2grid_hs.tif -z 5 -az 90
>  gdaldem color-relief points2grid.tif colorramp.txt points2grid_cr.tif
> -co compress=jpeg -co PHOTOMETRIC=YCBCR -co tiled=yes
>
>   Example pipeline:
>
>  <?xml version="1.0"?>
> <Pipeline version="1.0">
>   <Writer type="drivers.p2g.writer">
>     <Option name="filename”>points2grid</Option>
>     <Option name="grid_dist_x">1</Option>
>     <Option name="grid_dist_y">1</Option>
>     <Option name="output_type">idw</Option>
>     <Option name="output_format">asc</Option>
>     <Filter type="filters.selector">
>       <Option name="ignore_default">true</Option>
>       <Option name="keep">
>         <Options>
>           <Option name="dimension">X</Option>
>           <Option name="dimension">Y</Option>
>           <Option name="dimension">Z</Option>
>         </Options>
>       </Option>
>       <Filter type="filters.inplacereprojection">
>         <Option name="out_srs">EPSG:3857</Option>
>         <Option name="scale_x">1e-05</Option>
>         <Option name="scale_z">1e-05</Option>
>         <Option name="scale_y">1e-05</Option>
>         <Reader type="drivers.las.reader">
>           <Option name="spatialreference">epsg:26911+4326</Option>
>           <Option name="filename">pointcloudfile.laz</Option>
>         </Reader>
>       </Filter>
>     </Filter>
>   </Writer>
> </Pipeline>
>
>
>   --
> Michael Smith
>  US Army Corps
> Remote Sensing GIS/Center
>
>   From: Roger Bedell <rbedell at coordinatesolutions.com>
> Date: Thursday, December 26, 2013 at 5:15 AM
> To: Eran Nevo <eran at utilis.co.il>
> Cc: "pdal at lists.osgeo.org" <pdal at lists.osgeo.org>
> Subject: [EXTERNAL] Re: [pdal] PDAL and OpenLayers
> Resent-From: Michael Smith <michael.smith at usace.army.mil>
>
>   Hello Eran,
> Another possibility is to create DEM files from the LIDAR data, then use
> GDALDEM to create hillshaded tiles. I'm not exactly clear how to create the
> DEM files however...
>
>  One you have DEM files, I wrote a tool that can create a seamless
> hillshaded layer for GeoServer, then it is served up to OpenLayers the
> usual way via GeoServer.
>
>  http://rasternormalizer.codeplex.com/
>
>  Here is the result:
>
>
> http://204.62.18.181/OGI/search.aspx?mapcenterlon=-97.670532226558&mapcenterlat=34.802782432797&mapscale=11&Layers=58d1fa5c-6eb4-4b95-9f42-69cd7277e15d%2C4b945341-bc66-4c09-9df4-26fbb58e4a5b%2C&maptype=OLMap
>
>  Roger
>
>
>
>
>
> On Wed, Nov 13, 2013 at 5:20 AM, Eran Nevo <eran at utilis.co.il> wrote:
>
>>  Yes , it must be run through browser
>>
>> On 13 בנוב 2013, at 03:10, Chris Foster <chris.foster at roames.com.au>
>> wrote:
>>
>>  Does it need to run in a browser?  If not, I've been working on a
>> desktop-based lidar point cloud viewer which might help you out - see
>> http://c42f.github.io/displaz.  I'm close to a 0.2 release which will
>> include a binary installer for windows.
>>
>> Cheers,
>> ~Chris
>>
>> On 13 November 2013 01:26, Eran Nevo <eran at utilis.co.il> wrote:
>>
>> I'm looking for some kind of lidar viewer
>>
>>
>>  On 12 בנוב 2013, at 17:15, "Michael P. Gerlek" <mpg at flaxen.com> wrote:
>>
>>
>>  Eran-
>>
>>
>>  The sheer volume of point cloud data, as Howard says, makes it very
>> hard to
>>
>> display in a traditional web browser system, e.g. OpenLayers fed by JSON.
>>
>> You'll need to find a way to reduce the point count in a smart way - like
>>
>> feeding out a LOD (level of detail) algorithm.
>>
>>
>>  Two or three years ago, people started looking for good ways to do this.
>>
>> There might be an open source solution by now, but it would require
>>
>> something more heavyweight than just OpenLayers.
>>
>>
>>  _mpg
>>
>>
>>  On Nov 12, 2013, at 7:06 AM, Eran Nevo <eran at utilis.co.il> wrote:
>>
>>
>>  Oh , I'm looking for open source solution to show lidar on web
>> application
>>
>>
>>  On 12 בנוב 2013, at 16:40, Howard Butler <howard at hobu.co> wrote:
>>
>>
>>
>>  On Nov 11, 2013, at 12:21 PM, Eran Nevo <eran at utilis.co.il> wrote:
>>
>>
>>
>>
>>  Hi there ,
>>
>>
>>  Can anyone point me to an example how to implement PDAL with OpenLayers
>> ?
>>
>>
>>  I have LAS file and PostGIS db with points in them.
>>
>>
>>  Want to try PDAL.
>>
>>
>>
>>  OpenLayers is a web JavaScript technology. PDAL is a data translation
>>
>> software focused on transformations from one format to another. You could
>>
>> try using PDAL to export point cloud data to GeoJSON (using
>>
>> drivers.text.writer) and importing that into an OpenLayers map in some
>> way.
>>
>> You are very likely to overwhelm any browser, however, with any
>> significant
>>
>> amount of point cloud data.
>>
>>
>>  Howard
>>
>>
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>>
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>
>
>
>  --
> Roger Bedell
> Coordinate Solutions Inc.
>

-- 
Roger Bedell
Coordinate Solutions Inc.
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