Description
The topographic canvas is a set of topographical support points of high precision used as a reference to surveyors, topographers for field surveys.
It makes it possible to meet the obligation to link all topographic operations to the legal reference system RGF93.
These points are materialised in the field, calculated in XY coordinates (projection CC47) and Z (NGF-IGN69), identified on MSDS and made available to all.
It covers the entire City of Tours. Some points can also be found in the communes of Saint-Cyr-sur-Loire, Saint-Pierre-des-Corps, La Riche, Joué-lès-Tours and Chambray-lès-Tours.
It consists of 25 pairs of primary points (ex: P15001) calculated by GPS in post-processing, and 919 secondary points (e.g. S15051) calculated by traditional method.
HOW TO RECOGNISE A POINT IN THE CANVAS?
The landmarks are most often materialised by a survey nail and a CAT-engraved washer sealed at the edge of sidewalks and by terminals in non-urbanised areas.
Resources
| Name | Format | Description | Link |
|---|---|---|---|
| canvas-tours.zip | ZIP | Open resource | |
| canvas-tours.csv | CSV | Open resource | |
| canevas-tours.geojson | JSON | Open resource | |
| canevas-tours.json | JSON | Open resource |