GEOCASSINI AND NETWORK DETECTION

AVAILABLE DATA AND ITS STORAGE IN GEOCASSINI

Nature Where ? How ?
Orthophotos Open data DataBase Directory
Orthophotos Specific productions DataBase Directory
Cadastre Open data API
Network data Manager’s GIS DataBase Directory
Network detection Specific productions DataBase Directory
Lidar survey Specific productions DataBase Directory
Topographic plan Specific productions DataBase Directory
Survey of works Specific productions DataBase Directory
Occasional georeferencing Specific productions DataBase Directory

GOAL: carry out the plan for surveying the detection of networks

Example of a traditional survey

HOW:

• for linear detection zones or reasonable surfaces, by video capture of floor markings
• for larger areas, by using points clouds from lidar surveys

GOAL: obtain the georeferenced drawing of the detected networks.

OPERATING MODE for linear detection zones or reasonable surfaces

Using a Gopro, a smartphone or any other video sensor, the operator films the markings on the ground by moving along them

• without additional equipment if the surveyed area is previously covered by a digital twin in 3D point clouds
• by regularly noting GPS setting points in the opposite case

To note : The RezoCassini application, available on GooglePlay, is specially designed for assistance and the production of videos by smartphone.

Once produced, the video is transferred to GeoCassini, and the transformation of the video into colorized 3D point clouds is triggered.

A few minutes later (5 minutes on average), the point cloud is available to be georeferenced. Prior to the treatment, the user can also request an orthophoto of the raised area.

The user georeferences the point cloud verification in two ways:

• either from calibration points taken in the field (GPS), in the absence of a digital twin of 3D point clouds
• or by cloud/cloud calibration from existing point clouds in the work area

Once the georeferencing has been carried out, a table of deviations from the calibration points makes it possible to assess the precision of the georeferencing. The operation can be repeated to achieve the desired precision (centimeter).

The georeferencing validated, the file is saved in the DataBase and the project is updated automatically.

Bureau Veritas has certified the RezoCassini process according to standard NF S 70 003-3.

The “cloud/cloud” open trench survey using GeoCassini is 5 times more accurate than GPS methods.

With GeoCassini, the cloud/cloud methodology is much more efficient:

• no need for specific equipment (GPS)
• automated and fast processing because on the cloud
• time saving in stocktaking procedures
• much better accuracy than current GPS methods
• certified accuracy

The cloud/cloud calibration is based on the exploitation of the digital twin in 3D point cloud of the study area

• it is carried out before the work detection phase
• e-Cassini offers several solutions for having territorial digital twins: contact@e-cassini.fr

For larger areas

Result of a mobile mapping coupled with a georadar

They are surveyed with a georadar equipped with a GPS and towed by a vehicle.

They are also connected to a “mobil mapping” type lidar to have the inertial unit of the latter.

Note 1: the lidar mobil mapping simultaneously surveys the study area
Note 2: the inertial unit of the mobile mapping is used to georeference the trajectory of the ground penetrating radar

The georadar signal is processed in dedicated software and allows the 3D drawing of the detected networks.

The lidar data is itself processed separately in dedicated software.

Note 3 : if we have a digital twin of territory in 3D point clouds, the lidar data does not need to be processed.

RESULTS OBTAINED

For linear detection areas or reasonable surfaces

The georeferenced colorized 3D point cloud can be directly used in GeoCassini to draw the network survey plan at their exact depths. The plan can be drawn in 3D or 2D (orthophoto).

Result of a GoPro capture of network detection

Example of a top view drawing in the point cloud

• the result can then be exported in the main usual exchange formats
• the result can also be modeled in 3D with GeoCassini

3D modeling of networks with the right diameter

Georeferenced colorized 3D point cloud automatically updates territory digital twin

• it is a true 3D centimetric cartography of the underground networks which is thus updated
• this mapping represents a real challenge for improving
DT/DICT procedures

The entire process facilitates and simplifies subsequent interventions on the network

• The location of the networks is very precise and access to their positioning is possible through the e-Cassini marketplace.

• GeoCassini is interconnected with the augmented reality software vGis, which makes it possible to precisely identify the presence of underground networks in a study area.

Visualization of networks in the digital twin

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