Philippines use Taal Vulcano Eruption as Opportunity to become Very First Asian Country with Open LiDAR

UPDATE: As of January 30th also orthophotos and classified LAZ tiles are available for download.

It took just a few years of nagging, a vulcanic eruption, and then a few more weeks of nagging but now it has happened. The Philippines have become the first country in Asia to offering LiDAR as open data for free and unencumbered download. The portal created by the UP Training Center for Applied Geodesy and Photogrammetry (UP TCAGP) and their DREAM and PHIL LiDAR program already offers LiDAR-derived 1 meter DTM and DSM data flown between 2013 and 2017 as part of a national mission to aquire flood mapping data for a certain area around the Taal Vulcano. In the coming days orthophotos and the classified LiDAR point cloud will be added (at the moment the data is still undergoing another quality assurance review process).

As a quick test we went to the new online portal and downloaded the 34 DTM raster tiles that cover the Taal Vulcano Lake as seen in the screenshot below.

taal_vulcano_open_lidar_download_portal

Downloading the area-of-interest is easy with LiPAD’s nice download portal.

The downloaded 1 meter DTM tiles are in TIF format and each cover an area of 1000 by 1000 meter. However, they are overlapping because they have a 50 meter buffer, so that each raster contains elevation samples organized in 1100 columns by 1100 rows plus “no data” values. We use two LAStools commands to remove the buffers. First we use our new demzip to turn the TIF to RasterLAZ format. Use demzip from version 200131 of LAStools (or newer) as older releases did not handle “no data” values correctly.

demzip -i Taal\DTM\*.tif ^
       -olaz

The conversion from TIF to RasterLAZ also reduces the total file size for the 34 files from 157 MB to 27 MB. Next we remove the buffers using a new functionality in lasgrid (make sure you have the latest LAStools version 200112 or newer).

lasgrid -i Taal\DTM\*.laz ^
        -step 1 ^
        -use_tile_size 1000 ^
        -odir Taal\DTM_unbuffered ^
        -olaz

Without buffers the total file size in RasterLAZ format shrinks to 22 MB. Now we have the data in a format that can either be treated as a raster or as a point cloud. Hence we can use laspublish and quickly create a visualization of the Taal Vulcano Island with Potree which we then copied onto our university Web space for you to play with.  This was he are able to instantly create an 3D visualization portal that lets anyone do various simple and also more complex measurements.

laspublish -i Taal\DTM_unbuffered ^
           -elevation ^
           -odir Taal\DTM_portal ^
           -o TaalVulcanoIsland.html ^
           -title "DTM of Taal Vulcano Island" ^
           -description "DTM of Taal Vulcano Island" ^
           -olaz -overwrite

Below we see the result visualized with the Desktop version of Potree. You can access the interactive portal we have created here with any Web browser.

taal_vulcano_open_lidar_dtm

Visualizing the 1 meter DTM of Taal Vulcano Island as RasterLAZ point cloud with Potree to instantly create interactive portal allowing simple measurements that give an intuition about the height and the size of the vulcanic formation that makes up Taal Vulcano Island.

We would like to acknowledge the UP Training Center for Applied Geodesy and Photogrammetry (UP TCAGP) and their DREAM and PHIL LiDAR program for providing easy and unencumbered open access to this data with a license that encourages data reuse and repurposing. Kudos for being first in Asia to make open LiDAR happen!!!

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