Creation de mnt et masque d'eau au format d'entrĂ©e de MACCS – Readme.md

Readme.md

DTM and water mask tool as input for MUSCATE

This tool uses SRTM files from CGIAR-JRC processing, to provide the DTM used as input to MACCS/MAJA prototype, which includes also slope and aspect, at full and coarse resolution. It also uses SRTM water bodies files to produce the water masks used within MACCS. A special version for MAJA is described at the end of the Readme file, together with a conversion tool to obtain the input format needed for MAJA operational version

SRTM CGIAR files :

The DTM tiles (by tiles of 5 degrees) can be fetched here http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp More documentation on the product is avaiilable here : http://www.cgiar-csi.org/data/srtm-90m-digital-elevation-database-v4-1

SWBD

Documentation is available here https://dds.cr.usgs.gov/srtm/version2_1/SWBD/SWBD_Documentation/SWDB_Product_Specific_Guidance.pdf There was a ftp site, but it does not seem to be available. Data can be downloaded from https://earthexplorer.usgs.gov/

In "data sets", select

  • Digital Elevation
    • SRTM
    • SRTM Water Body Data

User manual

The tool requires a recent version of gdal (Minimum 1.11)

The parameter file, on my computer, is as follows :

INDIR_MNT =/mnt/data/DONNEES_AUX/SRTM
OUTDIR_MNT=/mnt/data/mnt
INDIR_EAU=/mnt/data/DONNEES_AUX/masque_eau
OUTDIR_EAU =/mnt/data/mnt

MNT means DTM and EAU means water

It also needs a file site. An example is provided : CVersailles.txt, which was used for SPOT4 (Take5), and 32SNE.txt, for Sentinel-2 tile 32SNE

  • proj is the projection name,
  • EPSG_OUT, is the EPSG code of the projection,
  • chaine_proj is the string to use to define it in gdal commands
    • you may find the information in the xml file provided with a granule : <HORIZONTAL_CS_NAME>WGS84 / UTM zone 32N</HORIZONTAL_CS_NAME> <HORIZONTAL_CS_CODE>EPSG:32632</HORIZONTAL_CS_CODE>
  • The 4 values can stay equal to zero to produce only one tile. They can be integers if you want to generate a grid of tiles. For Sentinel-2 only produce one tile at a time.

    tx_min=0 ty_min=0 tx_max=0 ty_max=0

  • pas_x and pas_y are the image size in m. Please keep the same values as below.

  • orig_x and orig_y are the coordinates of the upper left corner in m (gdalinfo can provide the information)

  • marge is the size of the overlap region between tiles For Sentinel-2, the margin is 0 as we produce DTM tile by tile due to the complex naming of tiles...

Here is an example for tile 32TSNE (in Tunisia)

proj=UTM32N
EPSG_out=32632
chaine_proj=EPSG:32632
tx_min=0
ty_min=0
tx_max=0
ty_max=0
pas_x=109800
pas_y=109800
orig_x=499980
orig_y=4000020
marge=0

Sentinel-2

A dedicated tool has been written for Sentinel-2 :

python tuilage_mnt_eau_S2.py -p parameters.txt -s 32SNE.txt -m SRTM

-c is the coarse resolution used to speed some proceses in MAJA. It is 240m.

This tool generates data with the format needed for the prototype version of MACCS

A converter is available to obtain the data format to use as input of MAJA (operational version)

python conversion_format_maja.py -t 32SNE -f mnt/32SNE