• Metadata catalogue
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Porsmilin topographic DEMs

In order to facilitate capturing three-dimensional beach change, full surveys of the subaerial beach have been conducted starting in 2004 using RTK-GNSS (survey method GPS), Unmanned Aerial Vehicle (UAV) imagery processed using Structure-from-Motion (SfM) photogrammetry (survey method PHO) and terrestrial laser-scanning (survey method TLS). For each survey, we prepared a Digital Elevation Model (DEM) at a fixed sampling distance of 0.5 m.
 
Citation proposal
Bertin Stéphane Bertin Stéphane Bertin Stéphane (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Floc'h France Floc'h France Floc'h France (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Le Dantec Nicolas Le Dantec Nicolas Le Dantec Nicolas (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Jaud Marion Jaud Marion Jaud Marion (UMS 3113 UMS 3113 UMS 3113 ) - Cancouët Romain Cancouët Romain Cancouët Romain (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Franzetti Marcaurelio Franzetti Marcaurelio Franzetti Marcaurelio (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Cuq Véronique Cuq Véronique Cuq Véronique (UMR 6554 LETG UMR 6554 LETG UMR 6554 LETG ) - Prunier Christophe Prunier Christophe Prunier Christophe (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Ammann Jérôme Ammann Jérôme Ammann Jérôme (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Augereau Emmanuel Augereau Emmanuel Augereau Emmanuel (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Lamarche Stevenn Lamarche Stevenn Lamarche Stevenn (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Belleney Déborah Belleney Déborah Belleney Déborah (UMR 6554 LETG UMR 6554 LETG UMR 6554 LETG ) - Rouan Mathias Rouan Mathias Rouan Mathias (UMR 6554 LETG UMR 6554 LETG UMR 6554 LETG ) - David Laurence David Laurence David Laurence (UMR 6554 LETG UMR 6554 LETG UMR 6554 LETG ) - Deschamps Anne Deschamps Anne Deschamps Anne (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Delacourt Christophe Delacourt Christophe Delacourt Christophe (UMR 6538 LGO UMR 6538 LGO UMR 6538 LGO ) - Suanez Serge Suanez Serge Suanez Serge (UMR 6554 LETG UMR 6554 LETG UMR 6554 LETG ) (2021) . Porsmilin topographic DEMs. https://services.mspdata.eu:/geonetwork/srv/api/records/f05f94ea-8801-4764-b61f-7e8cd5eccee1

Simple

Date ( Publication )
2021-03-11
Identifier
https://portail.indigeo.fr/geonetwork/srv/metadata/f05f94ea-8801-4764-b61f-7e8cd5eccee1
Credit
UMR 6538 LGO - UMR 6554 LETG
Status
Completed

  Author

UMR 6538 LGO - Bertin Stéphane Bertin Stéphane Bertin Stéphane  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Floc'h France Floc'h France Floc'h France  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Le Dantec Nicolas Le Dantec Nicolas Le Dantec Nicolas  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMS 3113 - Jaud Marion Jaud Marion Jaud Marion  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Cancouët Romain Cancouët Romain Cancouët Romain  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Franzetti Marcaurelio Franzetti Marcaurelio Franzetti Marcaurelio  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6554 LETG - Cuq Véronique Cuq Véronique Cuq Véronique  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Prunier Christophe Prunier Christophe Prunier Christophe  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Ammann Jérôme Ammann Jérôme Ammann Jérôme  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Augereau Emmanuel Augereau Emmanuel Augereau Emmanuel  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Lamarche Stevenn Lamarche Stevenn Lamarche Stevenn  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6554 LETG - Belleney Déborah Belleney Déborah Belleney Déborah  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6554 LETG - Rouan Mathias Rouan Mathias Rouan Mathias  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6554 LETG - David Laurence David Laurence David Laurence  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Deschamps Anne Deschamps Anne Deschamps Anne  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6538 LGO - Delacourt Christophe Delacourt Christophe Delacourt Christophe  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

  Author

UMR 6554 LETG - Suanez Serge Suanez Serge Suanez Serge  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

Keywords ( Theme )
  • SNO DYNALIT , Beach profile , Digital Elevation Model , Coastal monitoring , Nearshore waves , Astronomical tides , Bathymetry , Orthoimage
Keywords ( Place )
  • Brittany , Finistere , Porsmilin
GEMET - INSPIRE themes, version 1.0 GEMET - INSPIRE themes, version 1.0 ( Theme )
  • Orthoimagery , Elevation
Access constraints
Other restrictions
Other constraints
Pas de restriction d'accès public Pas de restriction d'accès public No limitations to public access
Use limitation
Free use subject to mentioning the source (at least the name of the producer) and the date of its last update
Use constraints
Other restrictions
Other constraints
Supplier partner is not able to guarantee the accuracy, update, integrity, completeness of data and in particular that they are free of errors or inaccuracies, including location, identification or qualification. No warranty as to the fitness of the data for a particular purpose is made by the supplier partner. Users use the data under their full responsibility, without recourse against the supplier partner whose liability can be incurred due to damage resulting directly or indirectly from the use of this data. In particular, it is up to users to decide, on their own responsibility: the opportunity to use the data; File compatibility of their computer systems; adequacy of the data to their needs; that they have sufficient competence to use the data. The partner supplier is in no way responsible for external elements including data analysis tools, hardware, software, networks ... used to view and / or process data. The user ensures verify the timeliness of the information provided is compatible with the use of it.
Spatial representation type
Grid
Spatial representation type
Text, table
Distance
0.5  m
Metadata language
Français French
Character set
UTF8
Topic category
  • Geoscientific information
N
S
E
W


Unique resource identifier
RGF93 / Lambert-93 + NGF-IGN69 height (EPSG:5698) RGF93 / Lambert-93 + NGF-IGN69 height (EPSG:5698) RGF93 / Lambert-93 + NGF-IGN69 height (EPSG:5698)
Distribution format
  • ASC (1.0 )

    Specification

  • GeoTIFF (1.0 )

    Specification

  • MATLAB (2018b )

    Specification

OnLine resource
Porsmilin_DEMs_topo.zip  

Porsmilin topographic DEM (2000-2019)

OnLine resource
MNT-Topo_Porsmilin_2003-2019  

Topographic DEMs - Porsmilin beach - 2003-2019 (WMS-T)

OnLine resource
SNO DYNALIT  

SNO DYNALIT

Hierarchy level
Dataset

Conformance result

Date ( Publication )
2010-12-08
Explanation
Article 7, paragraph 1, of Directive 2007/2 / EC corresponds to the technical procedures for interoperability: this is the regulation on interoperability: regulation n ° 1253/2013 of 21 October 2013 amending and supplementing Regulation n ° 1089/2010 of 23 November 2010
Pass
true
Statement
Six surveys of the subaerial beach excluding the surrounding reef were conducted between March and April 2004 using the GPS survey method. Surface coverage varied between a low of approx. 15,000 m2 and a high of 30,000 m2. The number of survey points varied between 272 and 543, corresponding to average distances between points within the range 3.8 - 4.4 m for the six surveys (μ = 4.08 m and μ = 0.25 m). To facilitate subsequent analyses and to allow comparisons with other surveys, those irregular point clouds were transformed into DEMs at a standard grid spacing of 0.5 m using triangle interpolation (function inpaint_nans in MATLAB), which uses known data points to calculate interpolated values at each grid node. Following preliminary testing, a threshold distance of 5 m was used to filter interpolated grid points judged too distant from a survey point to be reliably estimated.
Description
The dataset comprises 36 DEMs obtained using terrestrial laser-scanning (survey method TLS) spanning the period 2009-2019. TLS surveys start with the measurement of ground control points (GCPs) using RTK-GNSS for data georeferencing and verification. TLS scans were collected at 360° horizontally from different stations to achieve uniformly high resolution across the beach face and to reduce occlusions. Typically, two stations were used, positioned cross-shore centrally on the beach. In this situation, much of the subaerial beach is no further than 100 m from the laser head, resulting in a maximum ground sampling distance of approximately 0.1 m. A Riegl LMS-Z390i with a vertical scanning range of 80° and an angular resolution of 0.07° was used until 2014, progressively replaced by a VZ-400 of the same manufacturer allowing even smaller angular resolution at 0.04° and a vertical scanning range of 100°. Obtained point clouds were processed using the laser proprietary software RiSCAN PRO v1.7-2.0 for scan registration and geo-referencing (http://www.riegl.com/products/software-packages/riscan-pro/), and CloudCompare (http://www.cloudcompare.org/) for data interpolation into a DEM. The manufacturer stated positional accuracy and precision for the VZ-400 (LMS-Z390i) is 5(6) and 3(4) mm, respectively. This is an order of magnitude below the root-mean square errors (RMSE) we estimated using GCPs during processing, which show actual scan precisions of 0.026 ± 0.01 m (μ ± 1σ, n = 74).
Rationale
Survey method TLS
Description
Aerial surveys of Porsmilin have been conducted since 2006 using UAVs, starting with custom-built helicopters and multi-rotor drones equipped with a digital single lens reflex camera, through to nowadays use of ready-to-fly commercial drones such as DJI’s Phantom 4 Pro and Phantom 4 RTK. Obtained imagery was processed using the popular SfM method implemented in Agisoft Photoscan (now Metashape; https://www.agisoft.com/ ), in conjunction with GCPs (e.g., 30 cm-diameter red circular targets measured using RTK-GNSS), to produce geo-referenced DEMs and orthophotographs of the subaerial beach (survey method PHO). Following quality verification, six surveys were retained in the dataset spanning the period 2010-2019. Flying heights were typically around 80 m (maximum of 110 m), translating to a maximum ground pixel size of 0.02 m. Using some GCPs as check points (ChkPts) shows a photogrammetric 3D precision (RMSE) to be within the range 0.02 – 0.1 m ( = 0.044 m, σ = 0.037 m, n = 6).
Rationale
Survey method PHO
Description
To facilitate reuse of the DEMs obtained using different survey methods, and to allow direct comparisons, consistent grids and a standard planimetric resolution of 0.5 m were chosen to fit the entire dataset. Where necessary, DEM resampling was performed using linear interpolation (function griddata in MATLAB). To reduce operators’ influence on decisions such as filtering outliers and filling gaps in initial data, also contributing to homogenising survey precision across the dataset, all DEMs were applied the same post-processing routine that consists in (i) using the mean elevation difference parameter to filter DEM elevations outside the range μ ± 5σ, with  and σ calculated for each surface grid cell using a three-by-three moving window, and (ii) reasonably filling missing data by averaging at least three known elevations. For the latter, search is done within circles centred on the missing DEM cell with radii increasing incrementally (increment = grid spacing) until at least three known values are found or until a size limit is attained (1 and 10 m over reef and sand, respectively). Reef/sand classification was performed using a combination of orthoimage and roughness analyses. As a final step, DEMs were assessed for systematic and random errors using multi-temporal ground truths, obtained by averaging available surveys over stable terrain, with eventual corrections applied through horizontal and vertical registrations. DEMs are provided in separate folders in geotiff (.tif), Arcgrid ASCII (.asc) and MATLAB (.mat) formats. They are accompanied by detailed metadata text files and figure plots summarising the results of post-processing and error evaluation. The following naming convention is used: yyyymmdd_Porsmilin_SurveyMethod_L93_IGN69_0.5, where yyyymmdd is the survey date and SurveyMethod can be either GPS, PHO or TLS.
Rationale
DEM harmonization

Metadata

File identifier
f05f94ea-8801-4764-b61f-7e8cd5eccee1   XML
Metadata language
Français French
Character set
UTF8
Parent identifier
74ecce0a-e650-4c41-9970-97e4602f1cd8
Hierarchy level
Dataset
Hierarchy level name
Parent
Date stamp
2021-09-30T15:04:57
Metadata standard name
ISO 19115
Metadata standard version
1.0

  Point of contact

UMR 6538 LGO - Bertin Stéphane Bertin Stéphane Bertin Stéphane  
European Institute for Marine Studies, Technopôle Brest-Iroise, Rue Dumont d'Urville Plouzané 29280 France

 
 

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Porsminlin topographic DEM

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