Talk:Water Depth

SRTM data

Could it be interesting to make some sort of SRTM data set for waterdepths? If there are no free sources, maybe somebody could set it up? To harvest data, we need a system to record NMEA strings with combined position and depth information, and store it in a database. It will take time to harvest all the data, but it is a start. Maybe somebody even might be able to get a copy of hydrographic surveys into such a database? --Skippern 16:05, 1 August 2009 (UTC)

Depth / Bathometric data

As I am working on a seismic vessel at the moment, and witnessed the level of harvested bathometric data done in this part of oil exploration, I wonder how this data can be imported into a separate dataset such as SRTM. I talked with a client representative from Shell, and he believes that the oil companies (and the survey companies and national agencies for that matter) can easily release the bathometric data under PD license for free use, as long as the valuable data (to them) are separated from it. The oil companies are paying large sums of money for the data which is below the seabed, but in consequence of this are getting survey lines with (at the current project) 500m separations and sample points every 18m. Some surveys are done with all lines in a certain direction (single azimuth) while others are with data in several directions (multi azimuth), but as a result, bathometric data exists for extremely large parts of the ocean seabed, and with the right requests to the right departments can have all of this released or donated for our usage. --Skippern 08:12, 10 August 2010 (BST)

Chart datum

According to the page it's "A yet-unsolved problem". It is not. For ENCs (Electronic Nautical Charts), the reference is LAT. Dot. Old maps from the UKHO for instance were using another datum. They are sunsetting the printed maps making the ENCs their only reference.

For compatibility reasons, ENCs needed a universal datum and it's LAT. From time to time, the hydrographic agency may refine the LAT - the lowest tide level which can be predicted to occur under average meterological conditions and under any combination of astronomical conditions. (IHO Dictionary, S-32).

However several objects may define their own vertical datum.

Why should we reinvent the wheel? KISS: say that the reference is LAT and add a warning saying that some old or printed maps may use a deprecated datum. Anything against?

--Nospam2005 (talk) 22:02, 28 November 2022 (UTC)