Why and how evaluating generalised data?

This paper presents our proposal to evaluate generalised data from non generalised data. We propose a methodology of evaluation that decomposes the process of evaluation into sub-processes where the user can enter his own specifications and criteria of evaluation. We also propose different levels of synthesis according to the evaluation needs. The evaluation can be an 'evaluation for editing' to detect and correct generalisation inconsistencies, a 'descriptive evaluation' to describe more precisely how the data set represents the reality, or a 'evaluation for marking' to compare different generalisations. Of course working on data evaluation is also very useful to improve generalisation software. The proposed methodology is implemented on Laser-Scan Lamps2 GIS and has been tested on real geographical data base (the IGN-France BDTopo(C)) to produce maps at medium scale.