[Qgis-user] Vectorialization of cadastral raster maps

[venerio giuseppe anardu]

Hello to everybody,

Here in Italy we have the problem in convert cadastral coordinates Cassini-Soldner in other CRS. So, for survey purposes, I referenced a cadastral raster map in black and white (overlayed with a vectorial map and satellitar image to find proper control points and at the end check the referenced map) and digitize the parcels of interest. This operation is easy to do for some parcels, but would become very harsh if the task involves a large amount of parcels.
So I tested the "vectorialization" tool but the result was a little bit disappointing: I obtained a couple of saw-like lines divided in little sements that likely represent the two edge of each parcel border line; besides in the case of small parcels the result is unreadable. I tryed to use the simplify tool to try to enprove the results at least for the major parcels, but it doesn't positively affect the former result.
Does anyone have suggestions to accomplish this task?
Does exist a better tool to digitize a raster, maybe that draw a vector line in the middle of the raster lines? 
I used for several years ArcGIS in a company and I've found that ArcScan does a really good work in digitizing rasters and has a multiparameter raster snapping very useful: does exists some ArcScan-like tool for QGIS?

With many thanks in advance,

Venerio Giuseppe Anardu
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