Creating FMEAR Datasets from Surface Models/DEMs

Introduction

FME AR (FME Augmented Reality) is an app available for your mobile devices; both iOS and Android. Augmented Reality is essentially adding information to your real-world view (as opposed to Virtual Reality which is creating a totally artificial environment). FME’s AR app is powered by a data format called fmear.
This article covers how to create an fmear format dataset from an elevation model. The primary transformer to use is a SurfaceModeller, which creates a 3D surface from a set of input points.

The FME AR mobile app is still in development, and the articles in this tutorial series may not reflect its current state. The app should not be used in production. The FME AR mobile app for Android has been deprecated; see FME AR Mobile App on Android Deprecation.

Step-by-step Instructions

1. Read in Elevation Data
Start FME Workbench and open a blank workspace. Add a Canadian Digital Elevation Data (CDED) reader to the canvas and browse to the DEM-Full.dem dataset, which is available for download from the Files section on this article. 
 

 
2. Create TIN Surface 
Now we will create a TIN surface. Add a SurfaceModeller transformer to the canvas and connect the Points/Lines input port to the CDED reader feature type. 
 
In the parameters, set the Surface Tolerance to 10 and then disable Output Contours. 

 
If you were to run the workspace right now and inspect the TINSurface output port, you will see that the elevation looks extreme compared to the land area because the X/Y coordinates are in decimal degrees, but the elevation is stored in meters. We will fix this in the next step. 


 
3. Reproject X and Y
To fix the elevation issue, let’s reproject the coordinates to meters. Add a Reprojector to the SurfaceModeller TINSurface output port. 


In the parameters, set the Destination Coordinate System to UTM8-10. 

 
If you view the Reprojector output in Visual Preview, you will see that the vertical scale is more appropriate for the horizontal scales. 

 
 
4. Add Raster to Overlay
The model looks fine, but it might be better with a raster image overlaid as an appearance. The first step to do this is to add a reader for that raster.
Add a GeoTIFF reader to the canvas and browse to the VancouverImage.tif dataset. 

 
5. Set Appearance
Next, we will use the AppearanceSetter to apply the GeoTiff to the TIN surface. Add an AppearanceSetter to the canvas and connect the Appearance input port to the GeoTIFF reader feature type then connect the Geometry input port to the Reprojector. 


In the parameters, expand the Texture Coordinate Generation section then change Texture Mapping Type to Top Down Georeferenced. 

 
6. Write to FME AR
The data is now ready to write out to FME AR. Add an FME Augmented Reality (FME AR) writer to the canvas and browse to a location to save the data. Name the file VancouverDEM.fmear and click OK. 

 
In the Feature Type dialog, set the FME AR Asset Name to Vancouver and then click OK. 


Connect the Vancouver writer feature type to the Output port on the ApperanceSetter.


7. Run the workspace 
Run the workspace, then upload the dataset to either your phone or a cloud-based hosting platform such as Dropbox or Google Drive. The building model is now in fmear format and can be used in the FME AR app. 
 
8. View Dataset in FME AR
On your device, open the FME AR app. Point your device at a flat plane until the dot grid appears (tabletops or floors work best). 


Then click the orange icon in the bottom to open the file browser. Select the location of your dataset (or add it to your device). After the FMEAR model appears, you can toggle the layers on and off, we will have more layers in future parts. 

 
 

Data Attribution

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

It also includes data available from the U.S. Geological Survey.