h:En:Measuring Strategy

Deutsch	English

Water depth
Depth-Website
The project
Measuring strategy
Upload NMEA-data
Metadata help
Connecting NMEA-Logger
Hardware Logger
Software Logger
Mobile sounder
Ship network
Data formats

Simply measure where you are at the moment.
There is nothing special to do :-)
Switch on the logger before you sail off
and let it run for another half an hour after you have arrived.

Systematic Collection

Systematic Collection

We recommend to collect the data of your home port and the approach to the port systematically. Systematic collection is also advisable for anchorage bays, beaches, and buoy fields.

Important

navigate as close to the shore as your draft allows

navigate as close to any shoal as your draft allows

sail parallel lines in a distance of 10..50m

mark shoals on the map

Chaotic Collection

Chaotic Collection

In areas, where many skippers are on the way (for example at the fuel station in Palma, Mallorca), there will automatically be a dense collection of data by crowdsourcing. On the periphery of heavily frequenced ways, the density of measuring points is of course lower. In those cases of lower density, it helps to measure more systematically.

If you are at a mooring place, pier, or if you sway at anchor, don´t turn the logger off, so that a point cloud can develop. This helps us to calibrate the data.

• 

  Filling station in Palma

• 

  Point cloud

Collection under way

OpenSeaMap art

Sail your trip as usual.
Your track will be recorded automatically :-)

You can optimize the result:

• navigate as close to the shore as your draft allows,
  also when you are tacking
• navigate in a circle around a shoal as tight as possible
  and a second circle a little bit further
  and if possible, also sail through two shoals
• especially interesting are ports, bays, capes,
  passages through islands, and approaches.
  So, if such a site is on your way: take it!
• perform many manoeuvres in shallow water
• tack once in a while under motor in shallow water

Sometimes, an extra detour is an easy way to help ...

To cover interesting sites systematically (go around the port, looking for an anchoring place, go between buoys and anchoring ships)
navigate as close to the shore and to shoals as your draft allows.
Tacking and manoeuvres help to collect a broad track.

The most important data are those between 2 and 10m.
We analyse all data between 0 and 100m (200m).

Collection by Dinghy

Mobil measuring system

With a dinghy, with mobile GPS and sounder, you can measure very shallow banks. This is perfect for ports and anchorage bays. Children and teens love to use laytimes for such rubber boat trips!

About the Technique

• http://depth.openseamap.org/#introduction
• Further pages in the Wiki: see box in the upper right corner