in each LOD. The 
D2 by additional 
sed for modelling 
umns, or antennas. 
etries | gml Solid, 
> linked with the 
derived from the 
th the CityGML 
> differences and 
igrams are defined 
, Level of Detail 
...etc. (Tab.1) In 
ned with the UML 
o has aerial stereo 
program. Also, the 
the representation 
dels, issued by the 
| CityGML 
  
is 
| Yes 
Yes 
poke 
Yes 
Lu 
ERDAS LPS & 
Data models 
  
  
  
  
  
4. METHODOLOGY 
To use technologies, which make the work possible are Digital 
Photogrammetric Workstations, Erdas Stereo Analyst, Stereo 
Analyst and Feature Assist for ArcGIS, FME and CityGML as 
an accepted data model for 3D GIS. 
During the workflow the following 19 steps which are listed 
  
1. AERIAL IMAGES 
prim 
  
Farc 
tn ES FES ARC GIS 
       
    
   
  
  
  
   
First of all the workflow is described using different colours and 
in different boxes referring the different programs which are 
used during the thesis work. Also on the workflow diagram the 
number refers to the steps which are in order on the thesis 
workflow. (Fig.4.1) 
  
   
  
$f ERDAS LPS > | 8. IMPORT BLOCK 
z ERAPARAMETERS HRRAIN EDET OR 
  
VAINTERNAL ORIENTATION 
STEREOANALYST 
CP DIGETAUTERRAIN MODEL 
8-0. EDIT TERRAIN 
  
| FEATURE ASSIST 
  
  
YBR EXTERNAL ORIENTATION 
  
10 DIGITIZINGROOF 
11-12 ROOFTOP TOOLS 
  
  
4 GROUND CONTROL POINTS 
  
  
i 13 EXTRUDE ROOF BASE 
14.DEFINE ATTRIBUTES 
| 18 FOOTPRINTS 
  
  
  
  
5 BLOCK MODEL po A 
  
re 
ST IE ARC MAP 
  
  
1LEDIT ATTRIBUTES 
  
  
  
  
  
Figure 4.1: Workflow Diagram 
below: 
1. 
2. 
1 
r2 
1 
Ww 
14. 
15, 
16. 
17 
1 
2 
Adding Aerial Stereo images on ERDAS LPS and arranging 
to get 3D view 
Defining the camera properties associated with the camera 
parameters 
Orientation Parameters 
A. Interior Orientation Parameters 
B. Exterior Orientation Parameters 
Adding the Ground Control Points on ERDAS LPS 
Building a Block Model in ERDAS LPS 
Import the Block Model in the Arc GIS Stereo Analyst 
Adding a Digital Terrain Model in ArcGIS 
Editing the Terrain using the Terrain Editor 
Adding Terrain on Feature Assist 
. Digitizing the roof structure from Aerial stereo images in 
3D view using Feature Assist for ArcGIS 
. Chosing the roof template in ArcGIS Stereo Analyst to 
digitize it 
. Digitizing the building installations and merging with the 
building roof 
» Extruding the roof structure with Extrude Roof Base based 
on the terrain model. 
Giving the attributes of the building, 
Footprints of the buildings from Multipatch Shape file 
Converting from “Multipatch” to “Polygon Z” on FME 
Workbench 
+ Giving the attributes to the building's surface 
18. 
Converting the building data from “Shape” to “CityGML” 
on FME Workbench 
+ Displaying the CityGML data model in Land Explorer or 
Aristotales 
The result of the thesis work is a valid CityGML building 
model. In this paper work the aerial images were only the data 
which have been used within ERDAS LPS Program and the 3D 
city model have been created as a result. 
5. CONVERSION WITH FME 
In this chapter, the main aim is filling the gap between 
photogrammetric tools and the CityGML data model has been 
solved by adding several transformers in the FME program. The 
conversion part is divided into two main part: 
1. Conversion from ESRI Multipatch shape file format to 
ESRI PolygonZ shape file format with calculation of the 
building height. (Fig.5.1) 
  
    
   
    
    
   
     
    
  
   
  
  
  
    
   
   
   
   
   
    
  
   
   
   
   
   
   
   
   
    
  
    
     
   
   
   
    
  
  
  
Figure 5.1: Conversion from ESRI Multipatch to ESRI 
PolygonZ shape file