International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B3. Istanbul 2004
2. SOFTWARE ARCHITECTURE AND IMPLEMEN-
TATION
Figure 1 shows the software architecture of our solution. It
consists of the following 5 modules:
e InJECT core: basic functions, e.g. project management,
image navigation, zoom, main window, data import and
export, interactive 2D and 3D measurement.
e GIS interface: tools for vector data import/export based on
GML2, see subsection 4.1.
e Building extraction: tools for CSG selection, CSG
representation, matching, VRML representation, texture
extraction. Here we use the existing functionality of
inJECT (Gülch & Müller 2001, Inpho 2004).
e Parcel extraction: tools for the semi-automatic extraction of
area features, see subsection 4.2.
e Line extraction: tools for the semi-automatic extraction of
line features, see subsection 4.3.
Aerial
photographs
High-res satellite
images
ee |
| GIS Interface 3 !
=
; | inJECT Core | |
I I I I
1 1 TUM
1 Building Parcel Line !
! Extraction Extraction Extraction :
| | ICC
b a iue p en eam a mi m
Single houses Vegetation Road networks
3D Urbanareas 2D /3D
2D/3D
Figure 1. Software architecture for the generation and update
of VMapl and FFD GIS data
All modules are fully integrated into Inpho's software platform
inJECT. inJECT requires no special photogrammetric hardware
(stereo glasses, emitter, 3D cursor) and is easy to use even for
non-photogrammetrists since no stereoscopic viewing is needed.
Further software modules, e.g. for the extraction of topographic
or man-made point features, can be easily added, if required.
The software runs on standard PCs under the operating systems
Windows2000 and WindowsNT. It is object-oriented (C++) and
consists of a system core and several tools (plug-ins) which are
linked dynamically. Within the core module the GUI is
implemented using the class library QT (Trolltech), and the
XML import/export is based on the open source XML parsers
Xerces of the Apache XML project.
3. DATA BASE AND WORKFLOWS
The data base consists of the following data groups:
e Images including orientations
e Aerial photographs
e Satellite images
e Orthophotos
e Digital elevation models (DEM)
e VMapl, FFD and military basic vector data
The data flow is depicted in Figure 2. For the set-up of an
inJECT project at least one orthophoto or geocoded satellite
image (GeoTIFF or TFW) is needed. Multiple overlapping aerial
photographs can be incorporated as well. The camera and
orientation parameters can be imported as Z/I Imaging project
files (ASCII), MATCH-AT files or PHOREX2 files.
Optionally, elevation and vector data can be imported. As
elevation data ASCII_XYZ, Intergraph GRD or DTED data are
possible. The vector data is transformed from the VPF to the
GML2 format using the GIS import filter (see subsection 4.1).
Besides geometry, the imported GML data contains complex
information about feature semantics, which is read by inJECT as
well.
GIS Interface
FFD (VPF)
inJECT Core Module
Aerial photographs (TIFF,
b/w, color
Satellite images (TIFF,
b/w, color, multispektral)
Orthophotos (GeoTIFF,
b/w, color, multi channel
DEM (SCOP, ASCII_XYZ,
Grd
inJECT Parcel and
Line Extraction
| Stylesheets | Extracted Features
(XML,GML2)
(XSLT)
Stylesheet
Transformation
5 VMap1 (VPF) )
Figure 2. Data flow for the generation and update
of VMapl and FFD GIS data
The semi-automatic object extraction process is described in
detail within subsections 4.2 / 4.3 and results in new or modified
geometry and feature semantics. The resulting GML data can be
transformed back to VMapl or FFD data. Besides this standard
workflow, the resulting GML data can be transformed to DXF
or VRML using XSLT stylesheets. In case of a 3D extraction
the VRML data can be visualised using a VRML browser (e.g.
vrmlview).
4. METHODS AND ALGORITHMS
4.1 GIS Interface
For the handling of the GIS vector data, an interface between
inJECT and the GIS software packages Dynamo and GeoMedia
(Intergraph) has been developed based on the GML2 format
standard from the Open GIS Consortium (OGC). With this
interface the vector data and the associated XML schemes can
be automatically imported and exported. Imported features can
be edited within inJECT, the user can modify the geometry and
can select or key in the attribute values of each GIS object.
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