GEOCASSINI AND SEWERAGE NETWORKS

GOAL: to create the digital twin of a sewerage network to facilitate maintenance and improve hydraulic modeling resulting from its knowledge.

HOW: by integrating all the data available from the network into a digital twin of the territory, to promote updating and cross-exploitation.

AVAILABLE DATA AND ITS STORAGE IN GEOCASSINI

Nature Où ? Comment ?
Orthophotos Open data DataBase directory
Orthophotos Specific productions DataBase directory
Cadastre Open data API
Network data Manager’s GIS DataBase directory
Network geodetection Specific productions DataBase directory
Lidar data Specific productions DataBase directory
Topographic map Specific productions DataBase directory
Survey of works Specific productions DataBase directory
Occasional georeferencing Specific productions DataBase directory

REALIZE THE DIGITAL TWIN OF THE NETWORK UNDER GEOCASSINI

Example of digital twin on the agglomeration of Cholet (800km² area and 1500km of roads)

have the Lidar survey of the streets

• obtain 3D points clouds colorized points with centimetric precision and georeferenced. It is the digital twin of the territory concerned.
• it is carried out in mobile mapping
• supplemented by pedestrian acquisitions (Backpack, videos)
• possible rural areas can be acquired by drone

Survey with RezoCassini of a sewerage manhole

Example of dimensioning in a sanitation manhole surveyed with a 360 camera

> Lidar surveys of network parts (outcrops, manholes, drains, etc.)

Goal: to replace the traditional surveys of manholes by GPS filled in by sheets, which are themselves re-entered into the concessionaire’s GIS. This method is tedious and is a source of errors that are difficult to control.

• Surveys are taken with a small 360° camera equipped with an LED spotlight at the end of a telescopic pole. The user lowers the camera to the bottom of the gaze and raises it. A 360° video is obtained which, loaded into RezoCassini, is transformed into a 3D point cloud colorized, georeferenced points with millimetric precision.

• The “.las” files obtained are saved in DataBase and the project is automatically updated.

• We then have all the information that characterizes each manhole: diameters and waterways of the departures and arrivals of the connections, falls, riffles, slopes, heights, etc.

From this description, the 3D modeling of the camera passages can be calibrated to identify and geolocate the disorders in a pipe.

• The 360° camera can be attached to a “dog” type robot to survey large diameter pipes, crawl spaces, etc.
• The video signal from the 360° camera can be used by an artificial intelligence algorithm to detect structural disorders in the parts of the network.

Import available data from the network

• The territory’s digital twin represents the centimetric geolocated position of all outcrops in the network.
• It is therefore easy to correct the position of the imported data to “stick” to reality.
• If the 3D description of the manholes is available, the network
can also be repositioned in 3D, on the real values.

Example of discrepancy that can be found by importing data from the GIS before correction

Example of discrepancy that can be found by importing data from the GIS before correction

Correct network position relative to digital twin data

• The territory’s digital twin represents the centimetric geolocated position of all outcrops in the network.
• It is therefore easy to correct the position of the imported data to “stick” to reality.
• If the 3D description of the manholes is available, the network can also be repositioned in 3D, on the real values.

Example of a sewerage network, illustration of the visualization of several networks in 3D

Model the network in 3D

• GeoCassini makes it possible to model the network in 3D, from imported and corrected data.
• 3D modeling can be exported in IFC format; there is no longer any need for specific software for this task.

Representation of water pipes by laying date

GIS queries and sampling

• It is possible to request the metadata of the network and thus
display the network by nature of the pipes, age of the pipes, diameter of the pipes, depth of the pipes, etc.
• These queries can be synchronized with 3D modeling and IFC export.

Example of a GIS query on the installation date prior to 1985 on the sewerage manholes in the city of Angers (API)

Manage the detection of networks in the digital twin

• Network detections are based either on specific requests within the framework of the implementation of works, or on large-scale detections within the framework of the legislation on DT/DICT(France).

• In both cases, the customer/user systematically pays the cost of
“field” interventions for the georeferencing of detections. These
costs can be eliminated.

• In the context of specific interventions, the use of videos makes it possible to obtain the cloud of georeferenced centimetric 3D points of the detection with information on the nature of the network, trajectory and depth, without further field intervention (the GPS readings are no longer useful). It is then easy to plot the network in GeoCassini and export it in the desired format.

Example of Lidar survey after network detection

• In the context of large-scale detection: these detections are systematically carried out with ground-penetrating radar coupled with GPS and “mobile mapping” sensors. The use of digital twins of territories avoids paying for the production of single-use, non-replicable lidar data. This helps to significantly reduce the cost of geodetection and improve its accuracy (digital twin).

Result of a GoPro capture of network detection

Result of a mobile mapping coupled with a georadar

Note : in addition to cost reductions, the impact of this new methodology on the activity’s carbon footprint is significant and recognized through the “Solar Impulse Efficient Solution” label awarded to GeoCassini in March 2021.

Manage the verification of work in the digital twin (blind connections) (GED)

• the association of a digital twin of territory with the cloud-cloud assembly makes it possible to carry out work checks during the installation of the networks.

• Using a gopro, or a smartphone, the network placed in the trench is filmed, just before filling the trench. (RezoCassini application on PlayStore)

• GeoCassini automatically transforms the video into a point cloud. It is then georeferenced with the digital twin’s point cloud, and the record is automatically updated

Example of a survey of sewerage networks carried out with a smartphone

Note 1 : with this method, all underground and non-visible parts of the network are geolocated with centimeter precision.

Note 2 : by combining GeoCassini’s GED mode with this method, the referencing of the parts placed is automatically taken into account

Improve DT/DICT (France) procedures from the digital twin

The implementation of these processes makes it possible to considerably reduce the costs of the procedures because:
•the network is known with a better geometry
•the integration of network detections and verifications is fast and precise
•The data available under GeoCassini can be accessed from the GeoCassini marketplace, free of charge or with pricing depending on the network manager’s choice

Improve the geolocation of disorders

•Modeling of camera passages (ITV)
As soon as the network is perfectly calibrated with the digital twin, the camera passes can be modeled and georeferenced.
It is then possible to geolocate the identified disorders centimetrically.
•vGis

 GeoCassini is connected to the augmented reality software vGis which allows:

•to facilitate the marking on the ground of existing networks before intervention
•to visualize the position of the buried networks present in a given sector.
•precisely identify the position of a problem in a pipe.

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