Reversed Engineering of Data Model

Posted by Skippern on 22 October 2012 in English (English)

It sounds strange, and should not have been necessary, but since the people behind OpenSeaMap havn't been much of a help of documenting their data model (a few scattered wiki pages with not much readable structure is not documenting). The result have been that I have looked through the tools they have provided (Harbor tagging preset for JOSM and OpenSeaMap Editor plugin also for JOSM), which have given me something more useful to work with, and than started to search for common values with taginfo. The result have been that I have managed to structure their data much better. Things I tag with my reverse engineered data model actually start showing up on OpenSeaMap, something that proves that I am getting closer to the data model.

There are still a lot of things that I cannot get around, though it might be missing from their data model altogether as well. Taginfo doesn't return to me commonly used combination to these tags, as they still havn't enough occurances in the database. That means it is hard to know how to distinguish different types of restricted areas from each other, for example.

Another thing I am wondering about is how to get notes on objects that can show up in separate information boxes depending on map presentation. At the moment I am using note=

My JOSM preset and MapCSS for INT-1 will be updated when I get a chance, probably in a months time (they have been heavily edited compared with the ones on my web page).

Location: P-50

Comment from pieleric on 23 October 2012 at 13:11

On the wiki they state that they follow IHO S-57, which can be fully downloaded there: In the appendices there is a list of all objects and attributes possible.

Isn't it enough information? Maybe you could explain exactly the type of information you're missing on


Comment from Skippern on 2 November 2012 at 03:09

I know that they follow IHO S-57 which I have as PDF from IHO site, along with many other documents from IHO. It is rather annoying that they have decided to use S-57 as background, since that is a DATA TRANSFER MODEL, instead of INT-1 which is a SYMBOL MODEL also are published by IHO.

The wiki pages that describes the OpenSeaMap data model is rather unreadable, and doesn't describe the usage case for case (i.e. it took me a month to figure out how to tag seanark:type=wreck, and according to message from malcolmh that I received today I got it wrong)

To give a list of information I am missing, I could simply give you seamark:=

Except for what I have documented, there are close to nothing useful on the wiki.

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