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#1 2022-09-05 08:53:24

Registered: 2022-06-02
Posts: 2

Questions about the rule set to visualize OpenSeaMap data

I am trying to get my hands on the data, used in the OpenSeaMap webpage to visualize maritime objects.

Downloading OSM data via the overpass api, and setting a filter of ["seamark:type"] for nodes, ways, and relations does unfortunately not give me all the data that are visualized on the OpenSeaMap map. Using OSM data straight without the filter makes me drown in data I do not need and are hard to filter.

a) Hence, my first question would be: What is the correct way to get osm files, containing all the necessary data for the OpenSeaMap data, without having all the overhead of the whole OSM data?

Then there is the point of visualization. Even when taking the limited amount of data that I get when using the filter: ["seamark:type"], I can see there are a lot of points within a layer 'unknown_points'. Strangely, many of these points are actually with a style on the OpenSeaMap webmap, even though the attributes of the unknown_point layer do not indicate if e.g. a point is a buoy or the vertex point of an restricted area, or something else.

b) Based on what data / rule set was the decision made that these points from the unknown_points layer are of a certain type?
I am not saying the interpretation of the points is incorrect, I simply cannot recreate the map from the data given without any further information. And I am missing these information.

The last question I have is about the styles used for the OpenSeaMap webmap.

Obviously, there is a style file on some server, rendering the tiles for the map, yet there is nothing to my knowledge available for download from the OpenSeaMap project. Hence, am I wrong and there is a style file, or layer file available for download?

Bests Thomas

Last edited by TomGeo (2022-09-05 14:34:14)


#2 2022-09-11 07:50:22

From: Ruhrgebiet
Registered: 2013-10-27
Posts: 159

Re: Questions about the rule set to visualize OpenSeaMap data


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