On www.opensnowmap.org, nordic ski routes relations with a colour=* tag are now rendered automatically with an offset, up to three side by side. Don’t hesitate to provide some feedback if it looks strange on corner cases. Yves

This happens on 15.11.2022, somebody mapped the 100’000th kilometer of nordic ski piste. .

These are the trails tagged piste:type=nordic. They describe several practices : backcountry touring, classic style on prepared rails or skating on large groomed pistes. In OSM, they are distinguished thanks to the key piste:grooming=backcountry/scooter/classic/skating or classic+skating.

Yves - Opensnowmap.org

(original post in English)

Selon les régions considérées, la pratique habituelle du ski nordique est différente. Si en Europe de l’ouest, dans la grande majorité des cas on peut s’attendre à ce qu’une piste de ski de fond soit préparée avec un plan lisse pour le skating et au moins un paire de rails pour le style classique, ce n’est pas le cas partout dans le monde.

Dans certaines régions, la préparation des pistes est plus légère, et la pratique du ski de fond majoritaire est plutôt celle du « ski de randonnée nordique » avec des skis larges.

Sur OpenStreetMap, pour différencier ces pratiques très différentes, on utilise le tag piste:grooming .

Mais aujourd’hui (25.06.2022), pour 24 % des pistes de ski fond, soit tout de même 22’303 km, impossible de savoir quels skis prendre.

Alors cet été, à défaut de sortir la dameuse du hanger, à vos souris pour renseigner les pistes que vous connaissez !

… Gweld y cofnod llawn

Working on an upgrade of OpenSnowMap.org map style, I knew I had to add single trees mapped natural=tree, natural=tree_row and barrier=hedge. I figured out I had omitted them in my rendering when I was about to map some … that were already there.

When testing the new style, it comes out as a nice surprise that in some areas, countryside micro-mapping is really impressive :

Clearly, rendering all those trees gives a far better idea how the landscape look like there.

I expect that this new style will come live within a few weeks.

On 2nd April 2021, 70628 cross-country / nordic ski ways were members of one of 5849 route relations.

Among them, for 27423 ways, there is a piste:difficulty tag on the relation. I guess that the mapper estimated that the complete trail were ‘novice’, ‘easy’ or whatever.

But OSM is made by humans. We make mistakes. And we are very creatives. So, inevitably, there is 5625 ways where the difficulty of the way is not the same as the difficulty of the route, here are those differences:

Route difficulty	Way difficulty	Number of ways
novice	easy	70
novice	intermediate	15
easy	novice	195
easy	intermediate	463
easy	advanced	12
intermediate	novice	198
intermediate	easy	2607
intermediate	advanced	60
intermediate	expert	7
advanced	novice	53
advanced	easy	984
advanced	intermediate	766
advanced	expert	3
expert	easy	47
expert	intermediate	64
expert	advanced	2
extreme	easy	8
extreme	intermediate	2
extreme	advanced	8

What about those 12 easy trails with ‘advanced’ parts, which are, according to the documentation ‘Steep sections […], with narrow steep passages or sharp turns in steep passages, often icy pistes.’ Somebody is up for a bad surprise.

… Gweld y cofnod llawn

I found the piste:grooming description from the ‘Piste maps’ (osm.wiki/Piste_Maps#Grooming) or the Key:piste:grooming (osm.wiki/Key:piste:grooming) pages that was derived from the earlier not very clear. I’ve made an attempt to re-write it to document actual usage here:

osm.wiki/Talk:Key:piste:grooming#Page_rewrite_proposal

I’d like to have some comments if you think I missed something. This is about actual usage and better comprehension. If the values re-used from one type of piste to another does not suits you, it’s another story that can be dealt with later.

Yves

I’m genuinely pleased when people tell me about bugs or improvements related to OpenSnowMap map style by emailing me or by openning issues in github1,2. So, the least I can do is to try to fix them.

I’m happy to announce that a new style is being rolled out on OpenSnowMap that address some of them.

Here is an overview of the visible changes. For a better knowledge of the technical background, suffice to know that the piste database is now powered by Imposm instead of Osm2pgsql, and that the style is written in cartoCSS instead of bare mapnik XML.

Nordic and Crosscountry Skiing - Can I ski there ?

As the maintainer of OpenSnowMap, one thing I don’t want is to send your reckless grandma in an icy, treacherous slope. I’s also like to avoid to invite you to try an un-groomed backcountry piste you spot on the map with your skates.

So now, if piste:difficulty or piste:grooming is not mapped on piste:type=nordic ways, the piste shows a ? question mark on the map. Also, if not fully tagged, the more you zoom, the fainter the piste become. The goal of making the map less nice-looking is to ensure that lazy mappers will look twice at their contributions.

On the other hand, if you map properly the grooming type, icons and a dashed pattern will appears to distinguih between:

… Gweld y cofnod llawn

I’ve figured out recently that opensnowmap.org base map (topo) renders underground water pipes like plain rivers. It will need a database reload to fix this. Certainly I can correct other glitches at the same time, so have you spotted or can you find something else really wrong with this style? I’m mainly interested in mountainous places, of course, don’t expect fixes in Manhattan subway lines ;-) The style is derived from OSM-bright. Thanks in advance, Yves

No, seriously, c’mon!

I had to check on OSM.org to see if my Opensnowmap has a problem. No, it’s perfectly fine. But fine for who ?

It’s not like there is no mapper in the US, as at least one of them made something like this a very long time ago (6 years). Is there anybody in the US using OSM? Is there any US-based company using OSM? It seems a bit stupid to do so at first sight, isn’t it?

When Mapquest layer disappeared, this was a problem for OpenSnowMap: its cold colors and less detailed style were great to overlay ski pistes onto. But the end of this freely available map forced me to build a simple style with plenty of room for ski pistes: the OpenSnowMap Base Snow Map.

A winter topo map

I used OSM-Bright to start building this style. Using colder colours more suited to a winter map, of course I also added relief. In particular, relief hillshading led me to desaturate highways to avoid they pops out the shadowed side of the hills .

Ski pistes are not rendered on this layer, the OpenSnowMap remains an overlay. In fact, they are rendered on the Base Snow Map with 12 pixels wide transparent labels that forbids other labels to take place where ski pistes from the OpenSnowMap overlay will land.

I want to see it!

This style is only showcased on http://beta.opensnowmap.org for now. The mobile part of the website is shown with ‘retina tiles’ by default, but you can choose this high-dpi option or not from the menu.

For these mobile-friendly tiles, I choose to render 384px tiles and display them with a 1.5x scale factor. That please my eyes on my own phone and the server seems to be OK with them, so please tell me they also looks good on your phone or tablet.

Of course, Openstreetmap-carto is still available, although without high-res tiles but a simple scaling for the mobile version. Here also let me know what the default should be: I find it more usable with the scaling on my device, although a bit pixelized.

That’s great, but …

… Gweld y cofnod llawn

For those interested in DEM data, the release of void-filled, 1 arc-second and global SRTM data is now completed at USGS. See https://lpdaac.usgs.gov/nasa_shuttle_radar_topography_mission_srtm_global_1_arc_second_data_released_over_middle_east