About Physical layer

The 'Physical' layer which can be selected in the 'background' layers such as Google Maps, Satellite/Aerial imagery and Terrain layers has been created as a composite imagery got from several sources of data :

• 30 arc second global elevations grid model (bathymetry) from GEBCO,
• high-resolution Shoreline (GSHHS) from NOAA/SOEST and
• NGA vmap0 layers (lakes, rivers, political boundaries, green and relief areas...)

Contrary to nautical maps which are pre-processed and directly accessible on our servers, the raster tiles from this Physical layer are created on-the-fly by our map contour rendering engine in our servers.

This explains the display is much longer than for nautical layers.

More users will play with this layer in all regions of the world and for different levels of scales, more tiles will be created on our server, so available for all.

In the same time, the cache memory of the web browser will help to refresh faster when the user will display the same area.

Online live vessel traffic system

The GeoGarage team is leading some experimentation about the display of AIS live tracking online.

Using some specific hardware connected to a AIS receiver for sending AIS raw data automatically to the GeoGarage server (no need of additional PC), we have the following displays :

• Nantes/Saint Nazaire harbor with nautical maps overlay courtesy from SHOM (authorization for reproduction n°140/2008 for charts #7395 and 7396)
• Pointe à Pitre (Guadeloupe) harbor with nautical maps overlay courtesy from SHOM (authorization for reproduction n°409/2009 for chart #6948 and 7100)

Note : these two data flow are sent to MarineTraffic by GeoGarage for its own use

By the way, Marine GeoGarage is also studying the impact of nautical chart overlay on other Live AIS website such as :

• San Francisco bay ship traffic

About nautical chart updates frequency

The main advantage of the Marine GeoGarage server is to provide up to date nautical charts.

At this stage of the project, the time planning for the updates which depends on the distribution methods used by the different Hydrographic Services (HS) is the following :

• NOAA : every 2 months (today 1024 charts / 2223 including sub-charts)
• UKHO : every 3 months (today 667 charts / 1293 including sub-charts)
• Linz : every month (today 323 charts)
• Brazil : every month (today 242 charts)

* sub-chart : a paper chart might include a number of smaller detailed charts inset inside of it.

Note : in a future version of the Marine GeoGarage backend application, this scheduling will be reduced to match the update rating proposed the different HS servers (using automated distribution infrastructure provided by NOAA for example)

Historical maps

https://www.davidrumsey.com/view/google-maps

How to superimpose the past over the present and see both simultaneously ?

Quite simple with GeoGarage spatial image web server :

• World Globe 1790 : this globe shows contemporary discoveries in the Pacific as well as the routes of three of Captain James Cook's voyages...
• San Francisco 1859, one of th earliest maps of San Francisco Bay by the U.S. Coast Survey...
• nautical chart of Cuba (1775), showing ship tracks, rhumb lines, currents, depths by soundings...

Click on rumsey.geogarage.com to get access to 120 ancient maps from David Rumsey collection.

And don't forget to play with the transparent map slider option, it just gets better !

What about the source of the maps ?

The website has been derived in part from material obtained from different national Hydrographic Services (HS) with their official agreement :

• NOAA (US) : Raster Navigational Charts (RNC) ® from National Oceanic and Atmospheric Administration

• LINZ (New Zealand) : our website contains data sourced from Land Information New Zealand. Land Information New Zealand gives no warranty in relation to the data (including accuracy, reliability, completeness or suitability) and accepts no liability (including, without limitation, liability in negligence) for any loss, damage or costs relating to any use of the data. © Crown Copyright Reserved.

• Serviço Hidrogràfico Brasileiro : Marinha do Brasil , Copyright © Diretoria de Hidrografia E Navegaçao (DHN is not responsible for this use of their data)

• UK Hydrographic Office with the permission of the UK Hydrographic Office and Her Majesty's Stationery Office. The UK Hydrographic Office (UKHO) and its licensors make no warranties or representations, express or implied, with respect to this product. The UKHO and its licensors have not verified the information within our product or quality assured it. © British Crown Copyright, 2010

• GEBCO Digital Atlas from the British Oceanographic Centre (BODC) : the imagery (bathymetric contours) are produced on the fly from the GEBCO_08 Grid (version 20090202, 30 seconds) stored on our GeoGarage server (button 'Physical').

The catalog is expanding : additional nautical maps sources are in preparation. Stay tuned...