PDAL: Point cloud Data Abstraction Library

464 Pages·2017·21.18 MB·English

PDAL: Point cloud Data Abstraction
Library
Release 1.6.0
Andrew Bell
Brad Chambers
Howard Butler
Michael Gerlek
PDAL Contributors
Dec 14, 2017

CONTENTS
1 News 3
1.1 10-12-2017 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 About 5
2.1 About . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Download 13
3.1 Download . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 Quickstart 15
4.1 Quickstart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5 Applications 23
5.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6 Community 39
6.1 Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
7 Drivers 41
7.1 Pipeline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
7.2 Readers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
7.3 Writers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
7.4 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
8 Dimensions 185
8.1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
9 Python 189
9.1 Python . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
10 Tutorials 193
10.1 Tutorials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
11 Workshop 239
i
11.1 PointCloudProcessingandAnalysiswithPDAL . . . . . . . . . . . . . . . . 239
12 Development 323
12.1 Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
12.2 API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386
12.3 FAQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 451
12.4 License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 452
12.5 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453
13 Indicesandtables 455
Bibliography 457
Index 459
ii
PDAL: Point cloud Data Abstraction Library, Release 1.6.0
PDALisaC++BSD(http://www.opensource.org/licenses/bsd-license.php)libraryfor
translatingandmanipulatingpointclouddata(http://en.wikipedia.org/wiki/Point_cloud). Itis
verymuchliketheGDAL(http://www.gdal.org)librarywhichhandlesrasterandvectordata.
TheAbout (page5)pageprovideshighleveloverviewofthelibraryanditsphilosophy. Visit
Readers(page50)andWriters(page79)tolistdataformatsitsupports,andseeFilters
(page104)forfilteringoperationsthatyoucanapplywithPDAL.
Inadditiontothelibrarycode,PDALprovidesasuiteofcommand-lineapplicationsthatusers
canconvenientlyusetoprocess,filter,translate,andquerypointclouddata. Applications
(page23)providesmoreinformationonthattopic.
Finally,PDALspeaksPythonbybothembeddingandextendingit. VisitPython(page189)to
findouthowyoucanusePDALwithPythontoprocesspointclouddata.
TheentirewebsiteisavailableasasinglePDFathttp://pdal.io/PDAL.pdf
CONTENTS 1
PDAL: Point cloud Data Abstraction Library, Release 1.6.0
2 CONTENTS
CHAPTER
ONE
NEWS
1.1 10-12-2017
PDAL1.6.0hasbeenreleased. VisitDownload (page13)toobtainacopyofthesourcecode,
orfollowtheQuickstart (page15)togetgoinginahurrywithDocker
(https://www.docker.com/).
3
PDAL: Point cloud Data Abstraction Library, Release 1.6.0
4 Chapter 1. News
CHAPTER
TWO
ABOUT
2.1 About
2.1.1 What is PDAL?
PDAL(https://pdal.io/)isPointDataAbstractionLibrary. ItisaC/C++opensourcelibrary
andapplicationsfortranslatingandprocessingpointclouddata
(https://en.wikipedia.org/wiki/Point_cloud). ItisnotlimitedtoLiDAR
(https://en.wikipedia.org/wiki/Lidar)data,althoughthefocusandimpetusformanyofthe
toolsinthelibraryhavetheiroriginsinLiDAR.
2.1.2 What is its big idea?
PDALallowsyoutocomposeoperations(page104)onpointcloudsintopipelines(page41)
ofstages. ThesepipelinescanbewritteninadeclarativeJSONsyntaxorconstructedusingthe
availableAPI.
Why would you want to do that?
AtaskmightbetoloadsomeASPRSLAS
(http://www.asprs.org/Committee-General/LASer-LAS-File-Format-Exchange-Activities.html)
(themostcommonLiDARbinaryformat)dataintoadatabase,butyouwantedtotransformit
intoacommoncoordinatesystemalongtheway.
OneoptionwouldbetowriteaspecializedmonolithicprogramthatreadsLASdata,reprojects
itasnecessary,andthenhandlesthenecessaryoperationstoinsertthedataintheappropriate
formatinthedatabase. Thisapproachhasadistinctdisadvantageinthatwithoutcareful
planningitcouldquicklyspiraloutofcontrolasyouaddnewlittletweaksandfeaturestothe
operation. Itendsupbeingveryspecific,anditdoesnotallowyoutoeasilyreusethe
componentthatreadstheLASdataseparatelyfromthecomponentthattransformsthedata.
5
PDAL: Point cloud Data Abstraction Library, Release 1.6.0
ThePDALapproachistochaintogetherasetofcomponents,eachofwhichencapsulates
specificfunctionality. Thecomponentsallowforreuse,composition,andseparationof
concerns. PDALviewspointcloudprocessingoperationsasapipelinecomposedasaseriesof
stages. YoumighthaveasimplepipelinecomposedofaLASReader (page59)stage,a
Reprojection(page173)stage,andaPostgreSQLWriter (page98),forexample. Ratherthan
writingasingle,monolithicspecializedprogramtoperformthisoperation,youcan
dynamicallycomposeitasasequenceofstepsoroperations.
Fig.2.1: AsimplePDALpipelinecomposedofareader,filter,andwriterstages.
APDALJSONPipeline(page41)thatcomposesthisoperationtoreprojectandloadthedata
intoPostgreSQLmightlooksomethinglikethefollowing:
{
1
"pipeline":[
2
{
3
"type":"readers.las",
4
"filename":"input.las"
5
},
6
{
7
"type":"filters.reprojection",
8
"out_srs":"EPSG:3857"
9
},
10
{
11
"type":"writers.pgpointcloud",
12
"connection":"host='localhost' dbname='lidar' user='hobu'",
13
"table":"output",
14
"srid":"3857"
15
}
16
]
17
}
18
PDALcancomposeintermediatestagesforoperationssuchasfiltering,clipping,tiling,
transformingintoaprocessingpipelineandreuseasnecessary. Itallowsyoutodefinethese
pipelinesasJSON(https://en.wikipedia.org/wiki/JSON),anditprovidesacommand,pipeline
(page31),toallowyoutoexecutethem.
Note: Rasterprocessingtoolsoftencomposeoperationswiththisapproach. PDAL
conceptuallystealsitspipelinemodelingfromGDAL(http://gdal.org/)’sVirtualRasterFormat
6 Chapter 2. About