Development of the (Tuscan) Regional Topographic database(DB Topo) by means of Technical Map data (C.T.R. Carta Tecnica Regionale) reorganization.

The project involved experts in designing an object oriented multi-scale topographical database starting from the reorganization of Technical Maps (1: 10.000 scale 708 sections, 1:2.000 scale 4638 elements) and former databases (Hydrological, road and railway graphs).

The contracting authority required an integrated and multi-scale database by means of restructuring of regional technical maps integrated with conceptual, logical and topological features as defined by INTESA-GIS rules for topographical databases. The specifications for the structure of the database are therefore compliant with INTESA - GIS recommendation.

The project proceeded in six phases:

• Software design and optimization
• Upload and reorganization of input C.T.R. data
• Full topology building
• Creation of topographic database classes
• Topographic database 3D classes extraction
• Project analysis, fixing and deployment

ETL (Extraction Transformation and Loading)methodology was applied to the whole process. This approach allowed an optimal workflow through the use of:

• Transcoding methods
• Data handling techniques for errors and deviations
• Automated testing methods
• Data synthesis and data composition algorithms

The implementation of the DB Topo required the creation of a topologically consistent database. Therefore C.T.R. data (CAD structured) were reorganized by means of automated methods and by correction and data acquisition in order to be compliant with the requested object oriented structure. This operation has allowed the storage of geographic information and the correct data displaying and printing. To achieve these results, former topographic data were updated only when data were inconsistent, wrong, or, regarding graphs, not connected or missing.

ESRI ArcInfo coverage was used, in particular during full topology building. This data format is still considered as one of the best to store topological information, using both arc/node and arc/polygon topology complying with the technical requirements.

As results, the database collects the whole geometric and alphanumeric data contained in C.T.R. and graphs, keeping original information. Modified instances (arcs or nodes) are identified by an attribute and an unique identifier. Moreover, an attribute referring to data source was assigned to the archived records.

DB Topo was exported and deployed to local authorities as GML.