This thesis addresses easy and effective development of mapping and
transportation applications which especially focuses on the generation
of pedestrian networks for applications like navigation, itinerary
calculation, accessibility analysis and urban planning. In order to
achieve this goal, we proposed a two layered data model which encodes
the public space into a hierarchy of semantic geospatial objects. At the
lower level, the 2D geometry of the geospatial objects are captured
using a planar partition which is represented as a topological 2D
arrangement. This representation of a planar partition allows efficient
and effective geometry processing and easy maintenance and validation
throughout the editions when the geometry or topology of an object is
modified. At the upper layer, the semantic and thematic aspects of
geospatial objects are modelled and managed. The hierarchy between these
objects is maintained using a directed acyclic graph (DAG) in which the
leaf nodes correspond to the geometric primitives of the 2D arrangement
and the higher level nodes represent the aggregated semantic geospatial
objects at different levels. We integrated the proposed data model into
our GIS framework called StreetMaker together with a set of generic
algorithms and basic GIS capabilities. This framework is then rich
enough to generate pedestrian network graphs automatically. In fact,
within an accessibility analysis project, the full proposed pipeline was
successfully used on two sites to produce pedestrian network graphs
from various types of input data: existing GIS vector maps,
semi-automatically created vector data and vector objects extracted from
Mobile Mapping lidar point clouds.While modelling 2D ground surfaces
may be sufficient for 2D GIS applications, 3D GIS applications require
3D models of the environment. 3D modelling is a very broad topic but as a
first step to such 3D models, we focused on the semi-automatic
modelling of objects which can be modelled or approximated by
generalized cylinders (such as poles, lampposts, tree trunks, etc.) from
single images. The developed methods and techniques are presented and
discussed.
If you don't see the file, download it from the "download" icon
