Catalogue GéoSAS
Repository of hydrographic points for the Sélune scientific program
The removal of the dams of the Sélune is the subject of a scientific programme initiated in 2012 in which environmental parameters are monitored in order to provide real feedback on this restoration operation.
In 2019, a data observatory was set up to ensure the collection and processing of these parameters (biotic and abiotic). The data acquired from 2012 and at least until 2027 will be centralized through an information system (IS), called SISelune. SISelune aims to help scientists involved in the Sélune programme and make data accessible to all.
The Sélune scientific programme has a reference system, composed of points. These points can be used by all program actors to more easily identify any location within the study area. The points are created along the rivers, with an approach "Point kilométrique" (every 100m, going from upstream to downstream). Each of these points has a unique code, corresponding to the association of the watercourse (designated by a short code) and the distance to the source or confluence.
Since 2025, each of these points has also been characterized by its position in the watershed (downstream, upstream, ...) in relation to the zone determined by the former dams and their reservoirs, as well as their distance from the sea in 2 forms (LTM: Limite Transversale à la mer / Transverse Sea Limit and LSE: Limite Salure des eaux / Water salinity limit).
Simple
- Date ( Creation )
- 2022-06-14T00:00:00
- Edition
- 2025
- Identifier
- fr-18007003900276-umrsas-selune-v_ctxt_ref_point
- Purpose
- This layer shows the location of the points making up the Sélune scientific programme reference system. These points can be used to uniquely designate a location within the study area, regardless of the discipline or research project.
- Status
- Completed
- Maintenance and update frequency
- As needed
- Keywords ( Theme )
-
- Données ouvertes
- INSPIRE themes INSPIRE themes ( Theme )
-
- Installations de suivi environnemental
- Hydrographie
- Systèmes de maillage géographique
- Référentiels de coordonnées
- Use limitation
- Usage libre sous réserve des mentions obligatoires sur tout document de diffusion : "Source : UMR DECOD INRAE - Agrocampus Ouest"
- Use limitation
- Licence ouverte : https://www.etalab.gouv.fr/licence-ouverte-open-licence
- Access constraints
- Other restrictions
- Use constraints
- License
- Other constraints
- Pas de restriction d’accès public
- Spatial representation type
- Vector
- Denominator
- 25000
- Metadata language
- fre
- Topic category
-
- Environment
- Description
- Secteur hydrographique "I9" (correspondant à la Sélune de sa source à l'embouchure)
))
- Reference system identifier
- RGF93 / Lambert-93 (EPSG:2154)
- Geometric object type
- Point
Distributor
- Name
- ESRI Shapefile
- Version
- 1.0
- OnLine resource
-
selune:v_ctxt_ref_point
(
OGC:WMS
)
Visualiser
- OnLine resource
-
Télécharger au format Shapefile
(
WWW:DOWNLOAD-1.0-http--download
)
Télécharger au format Shapefile
- OnLine resource
- Observatoire Sélune ( WWW:LINK-1.0-http--link )
- OnLine resource
-
Télécharger au format CSV
(
WWW:DOWNLOAD-1.0-http--download
)
Télécharger au format CSV
- Hierarchy level
- Dataset
Conformance result
- Date ( Publication )
- 2013-12-10
- Explanation
- Non Evalué
- Pass
- No
- Statement
-
The points are created on watercourses using a “kilometer point” approach. The points are created along watercourses every 100 meters, from upstream to downstream. Each of these points has a unique code corresponding to the association of the watercourse (designated by a short code) and the distance from the source or confluence.
Since 2025, each of these points has also been characterized by its position on the watershed (downstream, upstream, etc.) in relation to the area determined by the old dams and their reservoirs, as well as their distance from the sea in two forms (LTM: Transverse Limit to the Sea and LSE: Water Salinity Limit).
The categorization of the point's position on the watershed was done manually by spatial selection in order to position the following values
- UPSTREAM: point located UPSTREAM OF THE VEZINS RESERVOIR (SELUNE AND TRIBUTARIES)
- DOWNSTREAM: point located DOWNSTREAM OF THE LA ROCHE QUI BOIT DAM (SELUNE AND TRIBUTARIES)
- RETENUE_R: point located in the LA ROCHE QUI BOIT RESERVOIR area (SELUNE)
- RETENUE_V: point located in the VEZINS SUR LA SELUNE RESERVOIR area (SELUNE)
- RETENUE_AF: point located on one of the TRIBUTARIES FLOWING FROM THE TWO RESERVOIRS
Two different distances to the sea have been listed in this dataset: the distance to the sea with reference to the Transverse Limit to the Sea (LTM) or the Salinity Limit of Water (LSE).
Two different distances to the sea have been recorded in this dataset: the distance to the sea with reference to the Transverse Sea Limit (LTM) or the Salinity Limit (LSE).
The LTM sea distance value was calculated as follows:
Step 1: determination of one (or more) reference point(s) for the change from sea to freshwater in order to calculate this sea distance.
Step 2: identification of the associated reference point(s) in order to assign them a distance to the sea equal to 0
Step 3: each reference point is separated by 100 m from its predecessor and successor and already has a distance attribute to the source. The distance to the sea is calculated step by step.
The LSE distance to the sea was calculated by difference with the reference value of 1,500 m.
Limitations: the reference system was created using sources (distance to source = 0) and then positioning a point every 100 meters. Therefore, when the reference system is traversed from the sea, there may be discrepancies and thus distances between two points of less than 100 meters (particularly in the presence of numerous confluence points and/or “parallel” channels). As a result, the distance to the sea information is more reliable when the associated Strahler number is high (a watercourse with a low number is a small tributary, and several confluences dot the route to the sea; each confluence can introduce an uncertainty of between 50 and 100 meters in the distance between two points). Despite this limitation, the distance to the sea calculated in this way provides comprehensive information on the watershed that is relevant at this scale.
- Feature catalogue citation
gmd:MD_Metadata
- File identifier
- 94077339-2ae8-4fe4-a5a0-7cbf3caaf826 XML
- Metadata language
- fre
- Character set
- UTF8
- Parent identifier
- Sélune scientific program 32b2d23e-0f67-46fb-ad72-110514f1c8ee
- Hierarchy level
- Dataset
- Date stamp
- 2025-08-13T14:40:11
- Metadata standard name
- ISO 19115
- Metadata standard version
- 1.0
Overviews
Provided by
