TIN from Point Data

Introduction

In this tutorial, you will learn how to create a Triangulated Irregular Network (TIN) from a 3D point dataset using the TINGenerator in FME. The TINGenerator in FME can create TINs from Points/Lines or Breaklines, whether the features are 2D or 3D.

Step-by-step Instructions

In this scenario, you want to create a TIN because you are interested in draping 2D features on a 3D TIN. This tutorial will only cover the TIN creation, but if you are interested in learning how to drape imagery textures on terrain surfaces, read the Draping Imagery Textures on Terrain Surfaces article.

Source
The source dataset is a point cloud containing elevation information. 


1. Create a New Workspace
Open FME Workbench and create a blank workspace. 

 
2. Add an ASPRS Lidar Data Exchange Format (LAS) Reader
Add an ASPRS Lidar Data Exchange Format (LAS) reader to the canvas by clicking on the Reader button on the top menu bar or by going to Readers > Add Reader. In the Add Reader dialog, select ASPRS Lidar Data Exchange Format (LAS) as the Format, then for Dataset browse to the ElevationPoints.las dataset which is available for download from the Files section on this article. Then click OK to finish adding the reader.

 
3. Create TIN
Click on the ElevationPoints reader feature type to select it.  Then add a TINGenerator transformer to the canvas by typing “TINGenerator” to bring up the list of FME Transformers in the Quick Add Search. Select the TINGenerator from the list of Transformers by double-clicking or by using the arrow keys and the Enter key to add it. Ensure that the reader feature type is connected to the Points/Lines input port. 


 
Double-click on the TINGenerator to open the parameters. In the parameters, set the Surface Tolerance to 100, then click OK. 

 
The ElevationPoints dataset we are working with contains approximately 1.4 million elevation points. Without filtering out points, the TIN would be very jagged and require more processing power. To reduce the number of points used to create the TIN, we needed to specify a surface tolerance. A larger surface tolerance value will speed up the surface model construction and simplify the TIN - the larger the value, the more input points will be filtered out. To learn more about Surface Tolerance values, see the TINGenerator Documentation.
 
4. Scale the Z Coordinate
Next, add a Scaler to the canvas and connect it to the TINSuraface output port on the TINGenerator. 

 
In the parameters, set the Z Scale Factor to 0.1, then click OK. 

 
The Z scale controls how high the features will be extruded from the ground. Lowering this will make the features look more realistic.
 
5. Run Workspace
Connect an Inspector transformer to Scaler Scaled output port. 

 
Run the workspace by clicking on the Run button on the top toolbar, or by using Run > Run Workspace on the top menu bar. 

 
After running the workspace, the output will be a 3D surface of the elevation of the area.  

Data Attribution

Data used in this tutorial originates from open data made available by the City of Vancouver, British Columbia. It contains information licensed under the Open Government License - Vancouver.