Research project T4/DD/24 (Research action T4)
The NIS wants to take advantage of new technologies to accelerate the work and make it more objective. NIS proposes to use a methodology developed by Laboratoire Surfaces based on an image processing system and on SPOT satellite images.
The succession of activities will be as follows:
1. Geometrical correction of SPOT images;
2. Merging of multi spectral and panchromatic images;
3. Tracing of the built area map by classification;
4. Delimitation of built areas and construction of a boolean mask; dilatation followed by erosion procedure (morphological closing) in order to regroup built areas closer than 100 metres from each other;
5. Selection of all built areas from 3.0 to 9.9 ha, from 10.0 to 19.9 ha and 20.0 ha and more;
6. Selection of all rural sectors to be redefined and of relevant high resolution digital orthophotoplans;
7. Creation of a selection of new statistical sectors by heads-up digitising on top of the selected orthophotoplans;
8. Boundary determination of urban agglomerations over 2500 ha, according to 200 metre EUROSTAT distance criteria;
9. Trial of a selection of new digital very high resolution images;
10. Printing of a selection of statistical sectors maps;
11. Updating of the DSECR street-file for a selection of redefined sectors;
12. Training NIS staff in charge of updating statistical sectors in the use of remote sensing and GIS techniques.
Laboratoire Surfaces is mainly required to deliver:
- a digital cartography with built areas appeared in areas with dispersed settlement since 1981;
- a selection of relevant orthophotoplans;
- a digital cartography with urban agglomeration boundaries determined according to 200 metres EUROSTAT criteria;
- a trained staff.
These deliverables will allow the NIS to finalise the statistical area partition, to determine its content in terms of street sections and buildings for the 2001 census and to propose urban areas for the future European urban statistical system.
