Viewing 10 posts - 1 through 10 (of 10 total)
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  • #8245
    giogio
    giogio
    Participant

    Dear Tobias,
    I would like to render this tag https://wiki.openstreetmap.org/wiki/Tag:natural%3Dcrevasse
    I think it could be useful for who are going on a glacier though now this tag is not used very.
    I think it could be rendered like natural=cliff http://wiki.openstreetmap.org/wiki/File:Cliff2.png
    What do you think about?
    I’ve added some crevasses here (they are not currently rendered on OSM)
    https://www.openstreetmap.org/#map=16/45.9171/7.0453

    Thanks a lot
    Best regards

    #8247
    Tobias
    Tobias
    Moderator

    Hi Giogio,
    natural=crevasse is not contained in the maps, so Christian has to add it to tag-mapping first before you can render it.
    I’m not so sure about the importance of it. It’s nice to have it in OSM, but if you are hiking on a glacier and definitely need to know where crevasses are, would you depend on OSM for that (meaning that you trust OSM to have every crevasse)?
    Best regards,
    Tobias

    Developer of Elevate mapstyle

    #8249
    giogio
    giogio
    Participant

    Hi Tobias,
    thanks for the reply.
    Yes I clearly understand your thoughts about this, I know that the crevasses are moving and they can’t stay in the same position, but usually they are where there’s a drastic change of inclination.
    In my opinion it is nice and important to see if there is some crevasses, it’s a sort of a warning, don’t you think?
    See for example the attached PCN of italy, the crevasses are about in the same position respect the aerial imagery.
    Thanks
    Best regards

    #8260
    ChristianK
    ChristianK
    Keymaster

    Hi,

    Basicly the idea of rendering these cracks is fine.
    However, if you look at the way they are mapped, its somewhat complicated to render these crevasses.
    While cliffs usually mapped as lines crevasses are mapped as areas or lines – in different ways as there is no commit about how to map this tag.

    Look here: http://www.openstreetmap.org/relation/4051805#map=15/46.8414/10.7479
    And make a query of this area: http://overpass-turbo.eu/

    [out:json]
    [timeout:25]
    ;
    (
      node
        ["natural"="crevasse"]
        (46.800411976139294,10.68746566772461,46.89386815592358,10.834064483642578);
      way
        ["natural"="crevasse"]
        (46.800411976139294,10.68746566772461,46.89386815592358,10.834064483642578);
      relation
        ["natural"="crevasse"]
        (46.800411976139294,10.68746566772461,46.89386815592358,10.834064483642578);
    );
    out body;
    >;
    out skel qt;
    

    This could be done by coloring these cracks with a slightly darker blue than the glacier.
    However, if an area of cracks is mapped as a whole including all cracks this would be more complicated couse no one nows the exact drection of the cracks.

    Third way to map this tag is by simply making lines as done on the Hallstätter Gletscher – for me the right way of mapping this tag.

    [out:json]
    [timeout:25]
    ;
    (
      node
        ["natural"="crevasse"]
        (47.47623076585981,13.605751991271973,47.48777400904015,13.624076843261719);
      way
        ["natural"="crevasse"]
        (47.47623076585981,13.605751991271973,47.48777400904015,13.624076843261719);
      relation
        ["natural"="crevasse"]
        (47.47623076585981,13.605751991271973,47.48777400904015,13.624076843261719);
    );
    out body;
    >;
    out skel qt;

    Well, I included this tag with the March-update for testing purpose only if @tobias has resources left for this.

    Best regards,
    Christian

    #8263
    giogio
    giogio
    Participant

    Hi Christian,
    first of all thanks for add this tag to the next OAM updates.
    I will also try myself to render this tag.
    As already noticed by you, I also think that they must be a line and not an area because it is the right way to drawn the direction of the cracks and probably can’t be done with the area, though many times the area of cracks is very wide and many lines are needed.
    I think also it is right to do it with a slightly darker blue line as you said.
    Thanks
    Best regards.

    @tobias
    Do you think aslo that the best way to render this tag is by using lines?

    #8267
    Tobias
    Tobias
    Moderator

    I think lines are better than areas because areas don’t show any direction; but lines might also slow down the rendering, if they are extensively mapped like here: http://overpass-turbo.eu/s/epz

    When maps with natural=crevasee are available I’ll test what is possible. I think if we render them, both ways and areas should be rendered. At the moment I got a light pattern in glaciers at higher zoom, let’s see if this still works with crevasses.

    PS – I just saw that those examples above are areas – there was someone working really hard at this

    Developer of Elevate mapstyle

    #8271
    giogio
    giogio
    Participant

    Hi Tobias,
    thanks for your efforts!
    Now we have to wait the next OAM update..
    Meanwhile, I thank you again (and also Christian) for all you effort in your great works.

    ps

    http://overpass-turbo.eu/s/epz
    PS – I just saw that those examples above are areas – there was someone working really hard at this

    WOW! really crazy!

    #8572
    giogio
    giogio
    Participant

    Hi Tobias,
    I’ve just tried to render the crevasses on the new OAM update of March
    by adding this code to the elevate theme (sorry for my poor knowledge of the code)

    <rule e="way" k="natural" v="crevasse" closed="no">
    		<line stroke="#88F7F7" stroke-width="1.50" stroke-dasharray="1.2,1.2" stroke-linejoin="round" stroke-linecap="butt" />
    	</rule>
    <rule e="way" k="natural" v="crevasse" closed="yes">
    		<line stroke="#88F7F7" stroke-width="1.50" stroke-dasharray="1.2,1.2" stroke-linejoin="round" stroke-linecap="butt" />
    	</rule>
    	<rule e="way" k="natural" closed="yes" v="crevasse">
    			<rule e="any" k="*" v="*" zoom-max="13">
    				<line stroke="#88F7F7" stroke-width="0.80" />
    				<area fill="#E8FFFF" />
    			</rule>
    			<rule e="any" k="*" v="*" zoom-min="14" zoom-max="14">
    				
    				<area src="file:ele_res_l/p_crevasse.png" />
    			</rule>
    			<rule e="any" k="*" v="*" zoom-min="15">
    				
    				<area src="file:ele_res_l/p_crevasse_large.png" />
    			</rule>
    </rule>

    I’ve also used the p_glacier_large.png & p_glacier.png for render large crevasses area and instead I’ve used, changing the original files removing the slightly blue lines for render the glacier zone without crevasses.
    What do you think? It could be better?

    Thanks
    Best regards

    #8582
    Tobias
    Tobias
    Moderator

    Hi Giogio,
    I already added crevasses to my dev version. It’s a bit more low key than your solution.
    I still work on something else and release the update when it’s finished.
    Best regards,
    Tobias

    Developer of Elevate mapstyle

    #8584
    giogio
    giogio
    Participant

    Ok,
    Thank you
    Good evening

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