Improving 3-D Buildings Into Realistic Objects

Miguel Pavon, TNRIS

Transcript

1. IMPROVING 3D BUILDINGS INTO REALISTIC OBJECTS TEXAS GIS FORUM 2019 FROM ZERO D TO 3D LOW and HIGH RES. BUILDINGS A LIDAR POINT CLOUD TO 3D BUILDINGS GALLERY.
2. GETTING CONSENSUS ABOUT DIMENSIONS 0 D 1 D 2 D 3 D
3. • Frequency: • 20,000 (20k) to • 340,000 (340k) pulses per second (Hz) • Point Spacing • 0.5 m. to • 1.4 m. • Multiple returns LIDAR COLLECTIONS
4. ADDRESS POINTS, PARCELS, LIDAR AND 3D BUILDINGS • LIDAR: • New lidar collections in 2019. • More to come in 2020-21
5. 10 STEP AGENDA 1. Check that the lidar collection has “buildings” as one of the classifications of the point cloud (LP360) 2. Create building footprint polygons (LP360) 3. If Digital Elevation Model is not available create it using “ground” classified points (LP360) 4. Create a Digital Surface Model using “ground” and “building” classified points (LP360) 5. Create a new raster mosaic for DEM if DEM tiles available from vendor (ArcGIS Pro) 6. Create a normalized Digital Surface Model (nDSM) subtracting the DEM from the DSM to get object heights (ArcMap or ArcGIS Pro) 7. a) Low-res version: using DEM, DSM, nDSM and building footprints extract the roof forms for buildings and Create 3D buildings (ArcGIS Pro) or b) High-res. using lidar cloud and footprints create 3D multipatch building 8. Enable and symbolize 3D buildings in a 3D Scene (ArcGIS Pro) 9. Review buildings and QA/QC the attributes, fix incorrect roof forms (ArcGIS Pro) 10. Next Steps
6. CHECK THAT THE LIDAR COLLECTION HAS “BUILDINGS” AS A CLASS
7. BUILDINGS CLASS
8. CREATE BUILDING FOOTPRINT POLYGONS (LP360)
9. CREATE DIGITAL ELEVATION MODEL (DEM) FOR GROUND
10. CREATE A DIGITAL SURFACE MODEL TILES USING “GROUND” AND “BUILDING” CLASSIFIED POINTS
11. CREATE A NORMALIZED DIGITAL SURFACE MODEL (NDSM) = DSM - DEM
12. 7A. LOW-RES VERSION • Using: • Digital Elevation Model (DEM), • Digital Surface Model (DSM), • Normalizes Digital Surface Model (nDSM) and • Building footprints (Feature class or shapefile) extract the roof forms for buildings and create 3D buildings with ArcGIS Pro (downloadable Roof_FormExtraction.tbx toolset)
13. USING DEM, DSM, NDSM AND BUILDING FOOTPRINTS EXTRACT THE ROOF FORMS
14. ENABLE AND SYMBOLIZE 3D BUILDINGS IN A 3D SCENE
15. REVIEW BUILDINGS AND QA/QC THE ATTRIBUTES, FIX INCORRECT ROOF FORMS
16. 7B. HIGH-RES VERSION • Using: • Lidar point cloud (classified) • Building footprints (Feature class or shapefile) Create 3D multipatch features with ArcGIS Pro (native 3D features toolset, LAS Building Multipatch tool)
17. LIDAR CLOUD AND LOW-RES 3D BUILDINGS
18. LIDAR CLOUD AND HI-RES 3D BUILDINGS
19. MULTIPATCH HI-RES 3D BUILDINGS
20. LIDAR CLOUD AND HI-RES 3D BUILDINGS
21. EXTRACTING INFORMATION … takes time and resources . . . but it is very useful in emergency situations and many other scenarios.
22. SO, HOW LONG IT WILL TAKE? • Consider billions of points as a portion of one collection (T2995 is one portion, Stratmap_2018_Upper_TX_Coast has 10 portions) • Get a Desktop computer with resources to process thousands of points a second for i.e.: 2D Buildings footprint delineation. • 1B points / 1K points/s = 1 M seconds • 1M Seconds / 60 s/min = 16,660 minutes • 16,660 min. / 60 min/hr = 277 hours • 277 hr. / 24 hr/day = 12 days
23. 3D BUILDING STATUS APP https://arcg.is/1iHmzD0 • 3D Buildings • Green – done • Yellow - processing
27. NEXT STEPS ? • Conflation • Census • Next Gen 911 Use • Repetitive Loss • Building type • Appraisal values • Texture • Texas Completion* • . . . * We will have buildings statewide a few months or a year after we complete lidar for the state (statewide lidar may happen in 2020-21).
28. QUESTIONS ? • 1700 N. Congress Av. R. B-40 Austin Texas, 78711-3231 ph. (512) 463-8399 fax (512) 463-7274 Miguel.Pavon@TWDB.Texas.gov