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Could you please introduce a new symbol in Open Street Map named 100-year flood plain? We have a lot of problems with floods recently in Slovenia and this is very useful for people and their building plans to know about this kind of informations. Because of more and more climate extrems occuring throughout the world, floods are also very important global problem and people have a right to be aware of this information.

All the best, Lana

asked 10 Nov '12, 15:14

Gasper%20Zemva's gravatar image

Gasper Zemva
accept rate: 0%

(20 Jan '17, 11:55) Piskvor

I asked a related question, which may be interesting to you.

(20 Jan '17, 14:11) andy mackey

I'm not quite sure what you mean by "100-year flood plain", but in OSM we generally (with few exceptions) map things that are visible on the ground right now - not things that are predicted, or planned, or historic!

One of the reasons for this approach is verifiability: We don't want opinion in OSM, we want facts. As long as everybody sticks to observable facts, everyone else can simply go and check whether the data accurately reflects the situation on the ground.

Having said that, everyone is of course free to display an OpenStreetMap map with a custom overlay on top of it that shows whatever it is they want to show - see for an example of how to overlay KML data on a map.

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answered 10 Nov '12, 16:01

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
accept rate: 23%

This list from taginfo might be helpful - it shows what other people have mapped with the word "flood" in the tag (although I'm guessing that a lot of those results may be via imports).

I'm not sure what you mean by "introduce a new symbol" though - perhaps you could explain? If you mean create a map layer that renders something that one of the existing OSM layer doesn't; well you can do that yourself. Or perhaps you mean in the Potlatch 2 editor?

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answered 10 Nov '12, 17:35

SomeoneElse's gravatar image

SomeoneElse ♦
accept rate: 16%


Thank you for your answers. Yes, I mean "introduce a new symbol" in the Potlatch 2 editor.

Answer on Frederik reply: The description of 100-year floods is on this link: The 100-years floods are visible in Slovenia right now.But probably they won't next month. Nevertheless, they cause severe damage, when they are occurring.

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answered 11 Nov '12, 16:53

flood%20layer's gravatar image

flood layer
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edited 11 Nov '12, 18:34

SomeoneElse's gravatar image

SomeoneElse ♦


This is an example of what does not belong in OSM. If the land is only expected to flood once every 100 years, adding it to OSM would give the impression that the land is prone to flooding often when it isn't.

It is a good example of something you might like to create as an overlay with an ordinary (or specialist) OSM map as a base map.

(11 Nov '12, 18:06) ChrisH
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question asked: 10 Nov '12, 15:14

question was seen: 5,900 times

last updated: 29 Dec '17, 11:07

NOTICE: is being shutdown on 1st March 2024. Please use the OpenStreetMap Community Forum