Map making

Land occupancy and use

Since 2006, maps of 20 to 30 land cover classes are generated every year, historically on an area of about 25*25 km centered on Lamasquère and Auradé sites, from time series of Spot, FORMOSAT-2, Landsat images, etc. (spatial resolution 30x30m). The ground coverage of this mapping varies from year to year depending on satellite images and reference data availability. The launch of the satellite Sentinel-2 enabled to extend the mapped area and increase spatial resolution, 10x10m.

Mapping of land occupancy and use in the South West of France in 2017 – spatial resolution 10×10 (by Claire Marais Sicre)

For more details about map-making methodology and map availability please contact Claire Marais Sicre.

Vegetation indices

Since 2006, mapping of the following parameters is available for the OSR study area: NDVI (Normalized Difference Vegetation Index), GAI (Green Area Index) and FAPAR (Fraction of Absorbed Photosynthetically Active Radiation). Maps are based on SPOT and FORMOSAT-2 image time series, validated using hemispheric field photographs according to the VALERI protocol and processed with CANEYE software.

For more details about map-making methodology and map availability please contact Valérie Demarez.

Snow cover and snow height in the Pyrenees Mountains

Since winter 2000, MODIS satellite data enables daily snow mapping with a spatial resolution of 500 meters. The FLUXPYR project analyzed data covering the Pyrenean massif between February 2000 and April 2011. Every 10 days, the 8 satellite-acquired images were merged to compensate for the cloud cover.

Mapping of the Green Area Index, spatial resolution ; 8×8 m (By Marjorie Battude)
Snow height mapping from Pléïades stereoscopic images in the Haut-Vicdessos watershed – spatial resolution; 5X5m (By Renaud Marty)

The snow height maps are generated annually from Pleiades stereo images with a spatial resolution of 5 meters, when snow cover is maximal.

For more details about map-making methodology and map availability please contact Simon Gascoin.

Brightness and surface temperature maps

Surface temperature map – spatial resolution : 30x30m (by Vincent Rivalland)

A tool allowing the automatic atmospheric correction of Landsat thermal bands (5,7 & 8) has been developed. An additional correction related to surface emissivity allowed us to provide a surface temperature map-making process. Thus, the following parameters will be amenable to mapping within the Landsat temporal and spatial coverage of the OSR study area:  surface brightness temperature, surface temperature and emissivity. A cloud mask may be added. The resolution, extent and frequency of the data that will be fed into the database will be those proposed by the USGS.

For more details about map-making methodology and map availability please contact Vincent Rivalland.

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