The GIS Project was ment to be a "playground" for any kind of geoinformational problem / challenge and we were completely free to choose any topic with relation to geoinformatics.
In a group of two we choose to work on a geodatabase to perform an accessibility analysis for the branches of an Austrian food supply company in Salzburg. All calculations have been performed
within the database and a GIS is only used to display the data. Our main focus was put on the excessive use of Open Source Software, such as Quantum GIS, PostgreSQL or the pgRouting-plugin for PostGIS.
What we wanted to do
The overall goal of this project was the calculation and visualization of catchment-areas of Spar branches in the city of Salzburg for three different types of movement (by foot, by bicycle and by car) on the
basis of a road-graph. Such an accessibility analysis could serve as a basis for the decision about the location of further branches and give a good overview of the market coverage of a company. Other very
important goals are the excessive use of open source software, such as PostGIS or Quantum GIS and the work with object-relational databases. During the semester's course we gained experience in working
with those spatial databases and their peculiarities.
A powerful open source object-relational database system. The database is used to store all geo-related content. This comprises mainly the road network, the Spar markets, the administrative boundary
area of Salzburg and tables for the analysis, the point clouds and alpha shape polygons for the catchment areas. The database runs as a server-service in the background and can be accessed through
clients like a WebGIS or a Desktop GIS like QuantumGIS.
Spatially enabling the PostgreSQL server and allowing it to be used for geographic information systems (GIS). PostGIS follows the OpenGIS "Simple Features Specification for SQL".
This means that all geo processing tasks can be performed with SQL queries and are stored in the PostgreSQL database in form of tables or views. PostGIS enables the PostgreSQL
database to additionally store the geometry type of a feature and his spatial reference system identifier (SRID) as columns in the specific table.
A web-based administration-tool for PostgreSQL. This tools allows a convenient manipulation of the database via a graphical user interface (GUI). You still have to know the SQL commands,
but you don't have to bother about issues like database connection strings etc. that normally have to be performed over a command line interface (CLI).
Extends the PostGIS geospatial database with routing functionality to perform our catchment area analysis. Therefore the driving distance function of pgRouting is used.
An open source Desktop GIS with PostGIS database and OpenLayer connection availability to visualize and analyze the database content.