Digital Mapping Project for Cellular Network Planning
TurkCell Iletisim Hizmetleri A.S.
Cities of Ankara, Istanbul and Izmir
The aim of the project was to produce a reliable digital map database for a cellular network planning system. The map data was converted into a customer’s specific data format. Project consisted of digital hybrid maps in PLANET 2.8 format for cities of Ankara, Istanbul and Izmir. The raster map resolution of these city maps was 12.5 metres. The digital raster maps in both cases consisted of two components: terrain height data and land use i.e. clutter data. Vector map consists of road network and some area (water, airfield and specific features) outlines. The mapping area is approx. 5,500 km².
Scope of the work:
- An aerial colour photography with DGPS projective centre registration at scale of 1:15,000 for each three city is carried out.
- Ground control is established by relative GPS survey.
- Every photograph is scanned with resolution of 21 microns, using a high precision PHODIS SCAI photogrammetric scanner.
- An aerial photo block is composed and a GPS-supported aerial triangulation performed for each city respectively.
- DTM for each city was generated in open areas by automatic extraction of elevation points from digital aerial stereo images. In dense urban areas the DTM was computed on basis of mass points and break lines digitized manually from stereo models.
- Digital orthophotos are produced for the project area
- Roads are digitized from orthophotos. Roads were divided into four classes by their width.
- Building heights are calculated by subtracting real DEM values from automatically generated Digital Surface Model values in same horizontal positioning for areas classified as building. Building height values are then classified into six categories.
- The clutter data is digitized from orthophotos and partly from stereomodels as vector polygons, and then converted into raster format. Classification is based on radiowave propagation properties as follows:
1) Sea Water
3) Open areas
5) Forest -10m
6) Forest 10m-
7-11) according to road classes
13-18) according to building heights
The co-ordinate system for the project is defined to WGS-72 Datum with UTM-projection appropriate for each city area, as this is supported by PLANET 2.8 cellular network planning software.