1. Modeling Unordered Point Data for 3D GIS Mapping
2 approaches for improved usability and accuracy

2. The Problem GIS rendering increasingly powerful/flexible
Precise, automated laser (LIDAR) point cloud data collection increasingly common
This benefits engineers and archaeologists
interested in highly detailed documentation
Common scenes still challenging in GIS
constraints in surface modeling, complexity
Important for archaeologists to incorporate buildings, caves, viewsheds into GIS environment.

3. Current Approaches True 3D in ESRI applications
Point cleaning and thinning

4. The Alternatives
This paper presents two alternatives to 3D modeling in the GIS, which facilitate the use of these types of models.
Modeling with 3rd party reverse modeling software
Converting and cleaning laser scanner data files

5. Project Goals
Make laser point cloud data usable and practical in the ESRI GIS environment
Priorities
Make files formats readable by GIS
True 3D surfacing (as opposed to 2.5D)
Georeference model
Integrate with other GIS layers in ESRI GIS
For point data, remove outliers
For point data, thin points by 50% for import

6. Unordered Point Cloud Data
point entities (x, y, z values)
lack topology- no network between points
can be imported into GIS and CAD as text files, and plotted as an event theme based on their provided coordinates

7. Unordered Point Cloud Data
Very common laser scanning file type
X, Y, Z, brightness
No topology

8. Two Approaches Surfacing Complex Scenes Point Cloud Cleaning
RapidForm, a reverse modeling software application
Several datasets - very simple (a statue), to complex (a large viewshed)
processing of the simple dataset most successful
Point Cloud Cleaning
custom application using Visual Basic and SQL
focused on the basic goal of file selection, conversion, and decimation based on user input

9. Two Approaches
Point
cloud
Each approach involves independent processing AND some level of import and integration in ArcGIS
clean
import
import
clean
thin
Cleaning Tool
decimate
triangulate
Export cloud
3D Modeling
Software
Fix normals
GIS
import
Fill holes
import
Interpolate
Restore detail
Export model

10. Surfacing Complex Scenes
Open point cloud
in modeling app
The “overhang” problem
What is “real” 3D?

11. Surfacing Complex Scenes
Remove excess/
unwanted points
Point cloud assessment and decision-making
Data reduction

12. Surfacing Complex Scenes
Clean
Triangulation
Normals
Surface repair

13. Surfacing Complex Scenes
Surface
Surfacing Complex Scenes
Thinning
Triangulation
Holes…

14. Surfacing Complex Scenes
Model to cloud fitting
Point density
Subdivision
Curvature/ heterogeneity

15. Surfacing Complex Scenes
Sharpening
Point Cloud Fitting
Smoothing
Spikes

16. Surfacing Complex Scenes
Enhancement and
analysis, etc.
Enhancement
Curvature Mapping
Face Angle Plot
Contours

17. Surfacing Complex Scenes
Convert
Surfacing Complex Scenes
File Conversion
Large .dxf files
Normals display in 3D viewers
Scale defaults

18. Surfacing Complex Scenes
Open .dxf in
GIS (ArcMap)
Perform
scale/geographic
transformation
Georeferencing
Coordinate shifts
Display bugs
Rendering

19. Surfacing Complex Scenes
Save as shapefile
Open .shp in
GIS (ArcScene)
Converting to native format
Dxf Shapefile
Coordinate transformations
Rendering

20. Surfacing Complex Scenes

21. 3D Modeling Workflow Clean Surface Convert Open point cloud
in modeling app
Remove excess/
unwanted points
Surface
(Perform
geographical
Transformation)
Fit surface
to point cloud
Convert
(Perform
geographical
Transformation)
Decimate by 75%
Enhancement and
analysis, etc.
Open .dxf in
GIS (ArcMap)
Open .shp in
GIS (ArcScene)
Perform
scale/geographic
transformation
Save as shapefile

22. Point Cloud Cleaning .pts file format and structure
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.pts file format and structure
Access database, template table
Error-checking and data import

23. Point Cloud Cleaning Point cloud spatial distribution Density
Brightness value

24. Point Cloud Cleaning CloudBurst point cloud cleaner File format
Statistics
Cleaning
Decimation

25. Point Cloud Cleaning CloudBurst point cloud cleaner File format
Statistics
Cleaning
Decimation

26. Point Cloud Cleaning CloudBurst point cloud cleaner File format
Statistics
Cleaning
Decimation

27. Point Cloud Cleaning CloudBurst point cloud cleaner File format
Statistics
Cleaning
Decimation

28. Conclusions
Laser scanning devices/LIDAR aid archaeologists and engineers in mapping complex features
So-called 3D GIS is not truly 3D enough to model laser point clouds effectively
Reverse modeling software produces superb, intricate models and has overlapping file formats with GIS
Expensive, difficult
Numerous gotchas related to scale and coordinates
Rudimentary point cloud cleaning and conversion software facilitates point cloud import and modeling in the GIS
Simple models only!
Decimation routine unacceptable- is there a solution?