Xynthia storm violently hits French Atlantic coast

Sailing boats out of the La Rochelle harbor

Saturday, Xynthia touched Portugal and Spain before crossing the French coast.

In Britanny and much of the Atlantic coast, these winds, coupled with very strong tidal factors, have led to a rise in sea level over a meter.

Links :

• flood impact for Ile de Ré
• Ile de Ré : Spot Image with Google Earth
  

Xynthia formed "when the cold winds of altitude, the famous jet streams very powerful, came into contact with a warm air mass situated in low layer" in the middle of the Atlantic at about 30 ° north latitude. The large temperature difference between the two air masses generated the "deepening" of a huge whirlpool, or depression, which was then evacuated to the northeast.
"These winter storms are relatively common but most of the time they are born farther north off Iceland and the British Isles and do not reach such intensity," says Patrick Galois, Meteo France Engineer.

The violence of Xynthia comes from the fact that it has been formed much farther south than usual and has mobilized a large amount of warm air.

Survey routes design made of parallel transects

http://gridcoverage.appspot.com/

This tool allows to create parallel profiles for a specific survey area just introducing 2 geographical points on the map (generally perpendicular to the general trend of the shore) and an uniformly-spacing distance between a selected number of profiles.

Application : optimization of bathymetric profiles in depth sounding surveys
Possibility to save the result in Olex format, kml for Google Earth display or CVS for spreadsheet and to play with a simulation tool to help to manage the reduction of costs involved in hydrography missions (calculating ETA on waypoints introducing boat speed for each leg)

What about ENC and Marine GeoGarage ?

geoTIFF raster (RNC) above and s-57 vector (ENC) below -courtesy from UKHO-

Vector maps (ENC in s-57 or s-63 encrypted format) are mainly used by onboard ECDIS or GIS applications.

Some Hydrographic Services have developed some servers using WMS OGC standards to deliver s-57 data to online compliant applications.

The Marine GeoGarage team is working on the possibility to display these maps online but using the pyramidal raster tiling scheme used in Google Maps, and also keeping the advantages of the additional chart info provided by the vector maps and stored in the geospatial database of the Marine GeoGarage server.

But as for the WMS access, it's not so easy to process raster tiles for the different scales using a rendering compatible with s-52 ECDIS presentation library which has not be studied for web application...

So additional work has to be done to provide both a reliable and sexy display for all map scales.

OpenSeaMap

OpenSeaMap is a starting OpenStreetMap subproject to create some free nautical map with contributions both from official public data (with no copyright) and passionated individuals.

As the backend structure for the data is based on the s-57 vector format (used by official ENC), it could be a good tool to :

• develop some cartographic online interface for implementing the info from the official Notices to Mariners (NTMs) which provides timely marine safety information for the correction of all the official navigation paper charts
• use the power of collaborative crowdsourcing for implementing nautical POI such as port information, marinas, repair shops, shipchandlers, marine electronic dealers...

Of course, this interesting initiative can't be a 'competitor' of the official Hydrographic Services which are using sophisticated technical means (multibeam, RTK GPS, Lidar...) in order to propose nautical charts more increasingly accurate.

In this way, as the final result is open to all, why not imaging some OpenSeaMap layer in the Marine GeoGarage to get official chart corrections from NTMs and a complementary marine local guide ?

What about Google Earth and Marine GeoGarage ?

Demo movie

Example of kml network link to Marine GeoGarage for viewing seamless all the NOAA raster chart dataset in Google Earth (GE).

Unfortunately GE does not react well to big dataset such as several thousands maps, even with the advanced and fancy features of the network links. We tried two different techniques and GE either ends up by struggling with the amount of data or showed ugly stuff while (slowly) refreshing.

Right now the other question is to know if there are some applications for users for this overlay and in this case how to distribute it.