This is a style to visualize the presence of simple roof tags on certain types of buildings (i.e. roof:shape, roof:colour). It helps mapping buildings for Simple 3D visualization from aerial views.

Please add ideas for further improvement at the bottom of this page.

meta   
{
        title: "Simple roof tags";
        author: "heilbron"; 
        version: "1.14_2021-06-21"; 
        description: "Visualize the presence of some simple roof tags (shape & colour)";
        link: "http://josm.openstreetmap.de/wiki/Styles/SimpleRoofTags";
        watch-modified: true;
}
        
area[building]
{
        z-index: 1;
        fill-opacity: 0.03; /* let the background, i.e. the roof, be recognizable */
}

area[building]["roof:colour"]
{
        z-index: 1;
        opacity: 0.9;
        color: (tag("roof:colour")); /* if a color is set, use it to color the outline ... */
}

area[building]["roof:colour"=red]
{
        z-index: 1;
        color: #A54040; /* ... but make red (#FF0000) a mixture of  brown and red */
        opacity: 0.7;   /* less intrusive */
}

area[building]["roof:colour"=lightgrey]
{
        color: #C8C8C8; /* ... but make lightgrey (#D3D3D3) a little darker*/
}

area[building]["roof:colour"=grey]
{
        color: #A0A0A0; /* ... but make grey (#BEBEBE) a little darker*/
}

area[building]["roof:colour"=darkgrey]
{
        color: #505050; /* ... but make darkgrey (#A9A9A9) quite darker*/
}

area[building]["roof:colour"=brown]
{
        color: #802020; /* ... but make brown (#A52A2A) darker*/
}

area[building][!"roof:colour"]
{
        z-index: 1;
        color: #101010; /* no roof:colour tag => make the outline look almost black */
}


area|z17-[building][!"roof:shape"] /* no roof shape set? => dash the outline */
{
        z-index: 1;
        width: 4;
        dashes: 3,3; /* any building WITHOUT a roof:shape tag (except fpr garages) gets a 4 pixel outline */
}

area|z17-[building=~/garage.*/] /* almost ignore roof tags for garages, i.e. make them all look the same */
{
        z-index: 0;
        width: 2;
        dashes: 8,1;
        color: #282828; /* garages get a thin, dashed, almost black outline, unless tagged otherwise */
}

area[building]["roof:shape"]
{
        z-index: 1;
        width: 5; /* any building WITH a roof:shape tag (except fpr garages) get a 5 pixel thick outline */
}

Styles_SimpleRoofTags-style.mapcss, Styles_SimpleRoofTags.zip

Ideas for improvements:

• Visualize the roof:orientation tag, i.e. using an icon.
• Make all visualized roof colours look a little darker (not just the ones adressed by the exceptions)
• Visualize also information that can be gathered by ground survey, i.e. roof:levels.