OpenStreetMap

hmmm

After faffing around with cities for a while I've only now realised the potential power of OSM for hiking trails (and bikes etc..). The ability to grade paths, update features quickly (lots of Coillte felling in Wicklow at the moment) and document paths not shown on other maps are big wins. It's a pity that Ireland is so bare at the moment.

I think I could get a few people involved uploading GPX traces for Irish hills but I'd need to demonstrate the "why" quite clearly. I know IrlJidel has done a lot of work in Dublin/Wicklow. Can anyone suggest other good examples of hiking trails done well on OSM - doesn't have to be in Ireland?

I appreciate also the need to avoid copyright problems. Can anyone suggest good sources of information that can be used to map Ireland from the comfort of the armchair? (e.g. Landsat is not particularly detailed or current).

mackerski

hmmm wrote: »

I think I could get a few people involved uploading GPX traces for Irish hills but I'd need to demonstrate the "why" quite clearly. I know IrlJidel has done a lot of work in Dublin/Wicklow. Can anyone suggest other good examples of hiking trails done well on OSM - doesn't have to be in Ireland?

It's always educational on OSM to watch what the Germans are up to - they represent the most active mapping community on OSM. A very good example of the kind of thing you are describing is the OSM Reit- und Wanderkarte (Riding and Hiking map). This takes OSM data, renders it according to styles considered useful for walkers, mashes this up with contours and terrain shading from another free source (SRTM) and produces an excellent map which can either be used online or installed on a Garmin device.

Another creative out-doorsy use is OpenPisteMap. Once again this is a contour-enriched map, but it takes care to render ski lifts and colour-coded pistes.

hmmm wrote: »

I appreciate also the need to avoid copyright problems. Can anyone suggest good sources of information that can be used to map Ireland from the comfort of the armchair? (e.g. Landsat is not particularly detailed or current).

In Ireland we have already had a data donation from moutainviews.ie which gave us all peaks over 400m. The other main source of armchair mapping data is aerial imagery - the only permitted source of this for Ireland at the moment is the Yahoo imagery, which only covers areas around Dublin, Cork, Belfast and Galway. While it does extend into much of the Wicklow mountains, it is not all that usable for trails - though it could be for forestry cover and other larger detail.

hmmm

That German map is spectacular, wow.

Any suggestions on a tag for felled managed forestry?

mackerski

hmmm wrote: »

That German map is spectacular, wow.

Any suggestions on a tag for felled managed forestry?

This is a tricky one. No tag for this is suggested under either landuse or natural. It's going to be a fairly niche tagging, I suppose - only walkers will care.

Usefully, OSM allows you to choose your own tags - if you choose well, others needing to tag the same thing will follow your lead. It seems to me that you could do a few things:

You could decide that a felled forest will at some stage be re-planted, meaning that it's best to treat the area as a special case of a forest (landuse=forest). However, you could add a private "sub-tag" of "forest=felled". Walking maps could choose to render this in a suitable way, where general purpose maps would not be rendered in a way that heeded the sub-tag, so would render the area exactly as it would a normal forest

Alternatively you could decide that it is wrong to have any map show such an area as a live forest. In such cases, instead of extending the existing forest tag you'd just choose a new one - something like landuse=felled_forest. Again, maps would process this differently. Most would ignore it completely, since their renderers would lack rules to handle your new tag. But a renderer supporting the tag could heed it.

When considering stuff like this, two suggestions:

1. Don't let it bother you that your work won't render straight away. Capturing the data is the main thing. If it bothers you that much you can work on your own private rendering and hope others will follow your lead.
2. Don't agonise too much over what tag name to use. If a better idea emerges it's fairly easy to batch-modify any objects using the old tag.

Any help?

hmmm

Thanks, I'll run with the latter based on your point about a felled forest potentially being represented as a fully grown forest for renderers that don't recognise some form of felled tag. Ultimately as a hiker I'd prefer a map to show an area bare then to show an area as a forest when the land is in an in-between state. A big win for OSM would be reasonably uptodate forest representations.

20 years time if the forest has largely grown and the original felled tag has not been removed I might think differently

larryone

I've started doing a fair bit on OSM for hiking trails. Unfortunately I dont have alot done at the moment, as the only GPS I have is a sh!te one. My decent one is on a trip to a foreign land right now.
Keeping the state of the forrestry up to date is a good idea, but requires the border of the forrestry to be put in first. It's not always that easy to walk the borders of the forrested land.
One thing I am looking into right now tho is getting the border of the Imaal artiliary range onto OSM.
The problem here is that signage tends not to last up in the hills, and there are some places where the border has changed considerably over the years.
Something that is not included on OSI maps is the larger restricted area (which includes Glenmalure) in operation on the days that they are actually shooting.

hmmm

larryone wrote: »

One thing I am looking into right now tho is getting the border of the Imaal artiliary range onto OSM.
The problem here is that signage tends not to last up in the hills, and there are some places where the border has changed considerably over the years.
Something that is not included on OSI maps is the larger restricted area (which includes Glenmalure) in operation on the days that they are actually shooting.

The army in Seskin hand out ordnance survey maps with the range highlighted. I would imagine that on that basis they would be able to supply detailed co-ordinates for their range limits?

larryone

hmmm wrote: »

The army in Seskin hand out ordnance survey maps with the range highlighted. I would imagine that on that basis they would be able to supply detailed co-ordinates for their range limits?

They gave me a ream of those maps. They're basically OSI Discovery Series style, but with the 2 hiking trails approved by the army marked in on them. Route 1 goes up Table Mountain, and I have part of this mapped. Unfortunately the batteries ran out in my gps so I dont have the full route yet. Route 2 goes up Lug via Camarahill, but needs to be re-surveyed, as it's track for a fair bit up Camara until you hit a gate, after which it's path.

I hope the army will be able to supply me with the info, as I'd say they provide same to OSI. I have the phone number for the Comandant, so will be talking to him soon about this.

hmmm

Some of these summits in Wicklow that were imported from Mountainviews are out by 50 metres from my own records - anyone else notice this?

mackerski

hmmm wrote: »

Some of these summits in Wicklow that were imported from Mountainviews are out by 50 metres from my own records - anyone else notice this?

In lat/long or elevation? If elevation, keep in mind that OSM is on a different datum. But I know that one other mapper has had reason to question the lat/long of Mount Leinster.

If you have a specific test case it might be worth addressing the Mountainviews community.

Alun

hmmm wrote: »

Some of these summits in Wicklow that were imported from Mountainviews are out by 50 metres from my own records - anyone else notice this?

Yes. I think this is mainly because many of them appear to be 6 figure references obtained by hand from the OS maps rather than obtained by GPS in the field or from digital mapping. A 6 figure reference is rounded down to the nearest 100m, so on average they would indeed be 50m off of their true location. It'd be a trivial (but mind numbingly tedious) matter just to import them into some mapping software and adjust them one by one according to the spot height on the maps.

The other problem is that in some cases the summit, as marked by impromptu cairns, wooden posts etc., doesn't always coincide with the spot height marked on the map, especially on some of the wide flat summits found in Wicklow. The question then is, which one is 'right'?

IrlJidel

hmmm wrote: »

Some of these summits in Wicklow that were imported from Mountainviews are out by 50 metres from my own records - anyone else notice this?

I did the original import using data kindly donated by mountainviews.ie.

When you talk about 'out by 50 meters' are you talking about position or elevation?

If elevation, then the discrepancy is due to us reporting the elevation as wgs84 which is about 50m different than the tm75 datum used in Ireland.

http://wiki.openstreetmap.org/wiki/Key:ele

When I did the import I explicitly indicated the ele:tm74 and ele:wgs84 elevation as well as inventing an ele:local tag to indicate the elevation used most commonly locally. All very confusing really.

That ele wiki page was updated suggesting people use wgs84 after I did the import but even now I don't think I would use the wgs84 elevation. I would think most people are using the local elevation as recorded from signposts and markers at summits.

For an example see:
http://www.openstreetmap.org/browse/node/332372529

If position is out, you could sign up to mountainviews and submit an updated reading. I did the summit import nearly exactly a year ago in Jan 09 so I could do a 2010 refresh.

hmmm

Alun wrote: »

Yes. I think this is mainly because many of them appear to be 6 figure references obtained by hand from the OS maps rather than obtained by GPS in the field or from digital mapping.

Yes sorry I should have clarified, the discrepancies are position - GPS versus OSM/Mountainviews.

A 6 figure reference is rounded down to the nearest 100m, so on average they would indeed be 50m off of their true location. It'd be a trivial (but mind numbingly tedious) matter just to import them into some mapping software and adjust them one by one according to the spot height on the maps.

They're not out by a lot, but I suppose for accuracy sake I would like to correct those where I am sure the summit isn't accurate. What is the etiquette about something like this - should I correct on the map itself or ask Mountainviews to update their data?

The other problem is that in some cases the summit, as marked by impromptu cairns, wooden posts etc., doesn't always coincide with the spot height marked on the map, especially on some of the wide flat summits found in Wicklow. The question then is, which one is 'right'?

Tell me about it Deceptive non-summit cairns are my pet peeve.

hmmm

Would anyone know if the Irish grid is copyrighted?

I've seen some attempts to overlay a British grid on OSM e.g.
http://forum.openstreetmap.org/viewtopic.php?pid=47354

Because there's relatively few trails on Irish mountains it would be very helpful if there was some way to overlay an Irish grid. I managed to get Mapnik up and running but that's where my skills end I'm afraid.

This is a nice attempt at a hiking map by someone in France I think (linked to Glendalough)
http://beta.letuffe.org/?zoom=14&lat=52.9948&lon=-6.36689&layers=0B000FFFFFFFFFFFF

mackerski

hmmm wrote: »

Would anyone know if the Irish grid is copyrighted?

Not sure about this - it's a question that has certainly arisen in connection with the GB grid. I do know that converting the projection to and from Irish grid is non-trivial.

hmmm wrote: »

Because there's relatively few trails on Irish mountains it would be very helpful if there was some way to overlay an Irish grid. I managed to get Mapnik up and running but that's where my skills end I'm afraid.

What would your goal be in this? Simply the ability to generate a map with gridlines to facilitate walkers using grid references?

hmmm

mackerski wrote: »

What would your goal be in this? Simply the ability to generate a map with gridlines to facilitate walkers using grid references?

Yup. In most parts of the world, trails are marked with signposts and usually a map with approximate locations are good enough for navigation. Not so in most parts of Ireland.

larryone

I would Imagine this is possible using open layers:
http://openlayers.org/