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#1 2018-01-07 15:50:23

From: Goes, the Netherlands
Registered: 2016-01-23
Posts: 17

Seasonal buoys

In the Netherlands we have a lot of buoys for recreational purpose which are brought on shore in the off season, and put back in spring.
Most of those with the same tags (position, colour, shape etc.)
At the Belgian coast a few buoys get the same treatment. For other countries I am not knowing.
The number of this type of buoys (a raw estimation) is 2000, out of a total number of 10000.
Example: … TFFTFFFFFF the yellow buoys “xx SVGM” and the green;white;green;white buoys further northwest are withdrawn this moment.
In OpenCPN those buoys are marked with “INFORM  Seasonal bouy only in period 0401 -1001” and visible in that application all year.

How to cope with this phenomena?

① In October (when removed from the water) delete from our database (OSM), and insert again in April.
Pro: showing on the map the real situation.
Con: a lot of work, and potential new errors. To repeat yearly.

② Using a tag (or tag combination) to mark those buoys as seasonal / temporarily not present.
Pro: One-time only operation.
Con: Adaptation of the renderer is needed to show the actual situation on the map.

③ ??

What is your opinion?


#2 2018-01-07 16:06:35

From: Hull, UK
Registered: 2012-09-05
Posts: 194

Re: Seasonal buoys

There are S57/S100 attributes for this situation: PERSTA & PEREND. In OSM these would be tagged: seamark:period_start=--MMDD & seamark:period_end=--MMDD, where MM is the month digits & DD the day digits. The "--" indicates recurrence every year. A once-only value would be in the form: CCYYMMDD.

Malcolm Herring, Developer


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