ExpOOs / Maison des Minéraux

Why analyse geographic relief

mcleaud — 2016-07-29T14:50:14Z

Using Litto3D® Data

The Litto3D® database is distributed as «Open Data» which allows free access and use for everyone.

These recent data have many applications, including risk prevention.

Flooding due to storm Xynthia confirmed the importance of precise mapping for the littoral zones exposed to marine flood risk.

Example application for marine flood risk

Marine flooding occurs when the sea temporarially inundates coastal areas higher than its usual tides. This «hazard» could have socio-economic impacts for the region.

Flooding zones identified by MNT Litto3D ® for Morgat (upper) and Camaret-sur-Mer (lower)

Flooding zones identified by aerial photos for Morgat (upper) and Camaret-sur-Mer (lower)

Flooding zone due to climate change (+ 60 cm in extreme scenario)

Flooding zone for high tide with a large tide coefficient

Flooding zone for an extreme scenario (high tide and 100-year storm)

Base level in 100 years (+ 60 cm)

Mean sea level (current base level)

Project resources

Le projet de recherche Cocorisco; COnnaissance, COmpréhension et gestion des RISques COtiers

http://www.risques-cotiers.fr/fr/boite-a-outils/guide-cocorisco

Application en ligne “Cartélie” pour la cartographie des zones basses littorales

http://cartelie.application.developpement-durable.gouv.fr

Le plan climat énergie territoire du Parc Naturel Régional d'Armorique

http://www.pnr-armorique.fr/Agir/Lutter-contre-le-rechauffement-climatique

Mapping, littoraly

amenez — 2016-07-29T14:22:09Z

Crozon Peninsula in Litto3D®
A playful exhibition to discover the litoral relief of the peninsula.
How to mesure geographic relief ? How to represent it ? Why analyse it ?
Play with the relief and challenge yourself !
Many thanks to the free software community (QGIS, Linux, Inkscape, SandBox, etc.). Thanks also to the people and organisations who contributed through sharing their Open Data. Big thanks to everyone whose support helped us realise this exhibition.
Exhibition created (…)

- Mapping, littoraly

How to measure geographic relief ?

amenez — 2016-07-29T14:21:51Z

The Litto3D® Project

The French cartographic services - “SHOM” for the sea and the “IGN” for the land - united their resources and their ability to measure, in high definition, the relief of the French costal zone, resulting in the Digital Terrain Model (DTM) dataset.

The three methods used

Topographic aerial laser (land)

Bathymetric aerial laser (sea)

Multi-bundles sounder (for underwater areas unaccessible by bathymetric laser)

Costal zones measured

For the sea, maximum limit of 10 meters in depth

White zones are areas without data

For the land, maximum limit of 2 kilometers inland

High definition : one meter resolution

Every square of 1×1 meter represents 3 values defining the geographic position : latitude, longitude and altitude. Combined, the squares form a network of data called a Digital Terrain Model (DTM).

SHOM : Service Hydraugraphique et Océanographique de la Marine

IGN : Institut Géographique National

How to represent geographic relief ? #2

mcleaud — 2016-07-29T14:21:31Z

From 3D to the cross section
The relief could be represented in several ways : 2D or 3D. The data for each are the same but the keys to read them are different.
2D Maps
Cross-section
Contour line of 25 m
3D Maps
Cross-section
Cross-section in 2D
Contour lines are formed by connecting points at the same altitude
Note : for cross sectional and 3D views, the altitudes are overestimated compared to reality. They are not the same scale as the horizontal distances.

- Mapping, littoraly

How to represent geographic relief ? #1

amenez — 2016-07-29T12:26:21Z

The secret of maps
Every map in the exhibition is the result of layering different representations of the geographic relief (Digital Terrain Model - DTM). This layering is done using GIS (Geographical Information System) software.
Final Map : fusion of different data layers
Contour lines layer
Contour lines link points of equal altitude. They are present every 5 meters.
Color spectrum layer
Maximum altitude
Minimum altitude
Shading layer
Lighting the surface of the DTM with (…)

- Mapping, littoraly