Archive for the ‘Openstreetmap’ Category

Paths and Tracks vs. Bridleways, Cycleways and Footways

Sunday, January 17th, 2010

My recent changes are more or less political. As always when it comes to presets, I will be accused to abuse my position as a software developer to influence the tagging done by mappers.

In the openstreetmap database, we have footway, cycleway and bridleway values for the highway tag for a very long time now. As they were not really sufficient to map trails in the woods, hills, or mountains, paths have been introduced back in 2007 to circumvent the limitations. During the introduction, it has been suggested that footways, cycleways and bridleways should be abandoned in favour of paths with some additional attributes. As many people objected, paths have been introduced and the other types are still “valid”.

This leads to the current situation where similar things are mapped differently. For example, a footway is tagged as

highway=footway

If bikes are allowed, a valid tagging scheme reads as

highway=footway
bicycle=yes

Unfortunately, this scheme does not really allow to map combined foot- and cycleways (as often found in germany). Thus some mappers use

highway=path
foot=designated
bicycle=designated

for such purposes.

As a consequence, we see

highway=path
foot=designated

as synonymous to

highway=footway

The three time-honoured tags still are very convenient to use, while the path tag combined with some additional tags is the more flexible one. I have no clear opinion on that matter, but I tend to sense that a single tagging scheme would be better when it comes to consumers (like renderers) of our data. If our editors were better and capable of hiding all the tagging stuff completely, I would clearly propose to abandon the legacy tags in favour of the path tag. But our editors aren’t, and mappers still must be aware of tags.

Besides the abovementioned tags, we also use

highway=track

sometimes accompanied by some surface or tracktype tags:

highway=track
tracktype=grade2
surface=gravel

This tag is for agricultural or silvicultural roads. Obviously the meaning of tracks, bridleways, cycleways, footways and the various flavours of paths is at least ambiguous. This sometimes leads to frustration of mappers.

Given the current tagging scheme, I do it this way:

  • If, and only if it is a dedicated cycleway, I use highway=cycleway (footway and bridleway respectively).
  • If it is a dedicated, combined foot- and cycleway, I use highway=path foot=designated bicycle=designated.
  • If a path is not used (or usable) by 4-wheeled vehicles like cars or tractors, it’s a path. I add widths, MTB or hiking scales to my likings.
  • Tracks are usually used by tractors. If so, it’s a track. I always add tracktype or surface tags, too.

That’s surely not a perfect solution, but lets me map most things i find accurately.

JOSM Presets updated

Sunday, January 17th, 2010
JOSM Logo

JOSM Logo

I rearranged the presets in JOSM and am prepared for the usual bashing :) .

Tracks and paths have been reunified into one menu entry only, so the convenience menu shortcuts to the various types of tracks and paths are past. OTOH, I have introduced dedicated menu entries for combined foot and cycleways:

JOSM presets - cleanup and additions

JOSM presets - cleanup and additions

The types have been included as popup menus into the dialogs. Besides tracktypes and hiking scales, I also included mountainbike scales, while more special tags for mountain bikers can be used by including an existing set of externally maintained presets:

JOSM - Path Preset

JOSM - Path Preset

Obviously, the dialogs are completely overcrowded. We will not be able to stuff any and all tags that will develop in the future into JOSM. Be prepared that I will do some major cleanup work some day.

External Presets in JOSM

Sunday, January 17th, 2010
JOSM Logo

JOSM Logo

JOSM provides the capability to include presets from external sources. It is the perfect mechanism for a group of mappers to maintain a specialized set of presets. This way, »Special Interest« mappers like skiers, mountain bikers or seamen can feed menu entries they need directly into JOSM without polluting the default menu space of JOSM.

Some examples are available via JOSM’s wiki pages. There’s also a page how to create and use such presets.

LinuxTag 2010 – Call for Papers

Sunday, January 17th, 2010

Due to some talks I held at the LinuxTag, I received an electronic mail regarding this year’s call for papers. They are explicitely looking for papers about Openstreetmap, but I won’t write one and have no clue whether anyone already offered one. If you are interested, better ask them before writing the paper to avoid duplicated work.

The State of the Snow

Sunday, January 17th, 2010
Hiking Trail in the Bienwald

Hiking Trail in the Bienwald

As Daisy had even reached the Upper Rhine Plain, we had some snow for a couple of days. I used the occasion for three nice hiking trips in the Bienwald, mapping grade 4 and 5 tracks, hiking paths and, last but not least, the stream Heilbach and some drains alimenting it:
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SRTM tiles available online

Saturday, January 9th, 2010

SRTM contours in Navit

A couple of days back, I converted the SRTM dataset into tiles containing OSM contour lines. Meanwhile the tiles are available online. This service is provided by the Stuttgart University of applied Sciences, thanks to the support of Dr. Franz-Josef Behr.

I hope the data is useful for some community work, e.g. tile rendering for slippy maps or rendering contour lines into viewports of mobile devices. If you create publicy available stuff from the data, please drop me a line.

Openstreetmap Data Types

Saturday, January 9th, 2010

osm_logo.png

The data of openstreetmap is stored in a relatively simple manner. Basically, we have three base datatypes:

  • Nodes are the most basic datatype and the only objects that actually contain geographical coordinates. A node may simply look like
    node id='12345' lat='48.9955' lon='8.3948'.
  • Ways are ambiguous. More or less, ways are just polygons, and can either describe a way or an area. Ways have no geoinformation itself, as they are relying on nodes:
    way id='23456' nd ref='12345' nd ref='12346'.
  • Relations have been introduced with API 0.5 and can be seen as data objects glueing together either nodes, ways, or both. Relations are used to model turn restrictions, routes, multipolygons and the like:
    relation id='34567' member type='node' ref='12345' role='' member type='way' ref='23456' role=''.
    The members of a relation can take a role to describe what they mean. In simple relations (like route releations) the role attribute often is left blank.

Simple plain text Tags are used to determine what kind of map feature a node, way or relation represents. A tag consists of a key-value-combination like amenity=bench, natural=water, highway=residential or route=ski. Mappers are invited to invent new tags whenever necessary. This freedom plays an important role concerning the success of the project.

Prior to API 0.5, we had Segments. A segment connected two nodes. First, tags have been applied directly to segments. Then, ways have been introduced which joined segments together. Since then, the tags have been applied to the ways instead of the segments. Segments caused some trouble (namely “unordered segments” for the old dogs) and have been abandoned during the introduction of API 0.5.

So nowadays we have nodes, ways, relations and tags. Easy, isn’t it? True for nodes, ways and tags. Not true for relations, though. Relations are difficult to create and edit, because they most often have no direct graphical representation in the editors. More or less they appear a bit flange-mounted on top of nodes and ways. Nevertheless they allow us to map things that otherwise would be difficult or impossible to model.

Continued mapping of Black Forest ski runs

Thursday, January 7th, 2010

In addition to some prior mapping of black forest ski runs, I’ve been on-site again last sunday. Meanwhile, Langläufer contacted me due to my mapping activities. I’ve now tagged the route relations according to the tags he currently renders. Here’s the result as seen on his map:

Cross-country ski runs near Herrenwies

Cross-country ski runs near Herrenwies

The map is similar like Openpistemap or the Hiking and horseback riding map created by Nop. Some collaboration or mashups would be great.

Mapping towns of northern Hesse

Monday, January 4th, 2010

During the holidays, I continued mapping Kaufungen (and Helsa), where some residential areas were still missing. I was surprised that no other mapper found it during last year’s course:

There are still some details missing, namely streets south of the station (thus the marker). If I have good luck, those will still be missing next X-mas :) .

Mapping the Ottertal, Part II

Monday, December 28th, 2009
Ottertal Fungi

Ottertal Fungi

Due to the annual Xmas family meeting I had the occasion to do some further mapping of the lovely Ottertal. Unfortunately my camera failed after I had taken four pictures, but that’s better than nothing :) .

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Mapping black forest ski runs

Sunday, December 20th, 2009
Snow of the black forest near Herrenwies

Snow of the black forest near Herrenwies

The winter arrived in europe, and even in Karlsruhe with its mild clime some snowflakes and temperatures less than -10°C have been detected sporadically. Surprisingly there’s not much snow at the nearby black forest yet (only about 20cm respectively 8″), but it seems to be enough for winter sport activities.

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Article about Openstreetmap on mobile devices online

Sunday, December 13th, 2009
Pencil (by openclipart.org - public domain)

Pencil (by openclipart.org - public domain)

The german Linux Magazin put the article about Linux on mobile devices online.

I’ve ranted about writing the article back in November and October. If you didn’t read the printed issue, the online article is another occasion.

Another interesting article is Wirbelstürmer which reports about the usage of OSM and openrouteservice.org to cope with the remains of the hurricane »Ike«. Thanks for putting those articles online, guys!

Mapping rivers in the woods ++

Sunday, December 6th, 2009
Brown and brown

Brown and brown

Though it was a cloudy (and rainy) day, I needed some compensation for the many extra office hours of the last week. During the winter months, I try to map hiking paths and rivers in the Bienwald, which I cannot map by bike during summer:

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Mapping rivers in the woods

Thursday, December 3rd, 2009
Some Lichen

Some Lichen

No posting for more than one week? Isn’t there anything interesting to write about? There is, but the release of interiorcad keeps me busy.

Due to the lack of daylight in my spare time, I decided for a short hiking trip last sunday, though it was a rather rainy day. I had good luck: The rain stopped as I reached on-site and it began raining again just as I reached the car after the trip.
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Mapping the Ottertal

Sunday, November 22nd, 2009
Fungi of the Ottertal - 1

Fungi of the Ottertal - 1

Yesterday we celebrated the 60th birthday of my mother at the village where I grew up. A nice occasion to meet family members and other people I haven’t seen for a very long time.
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OSM-Booth at OpenExpo, Karlsruhe

Sunday, November 15th, 2009
OSM-Booth at OpenExpo, Karlsruhe, Germany

OSM-Booth at OpenExpo, Karlsruhe, Germany

The OpenExpo just opened. Both OSM as well as KaLUG are manning a booth. As last year, there aren’t many visitors yet, but this will change until noon.

OSM@Open Source Expo one week ahead

Sunday, November 8th, 2009

osm_logo.png

The Open Source Expo is less than one week ahead. We will populate a booth, as do our friend of the Karlsruhe Linux User Group (aka KaLUG).

If you want to attend or help, please see this Wiki-Page for details.

GPS-Articles in the current issue of german Linux Magazin

Thursday, November 5th, 2009
Gebabbel Logo

Gebabbel Logo

The current issue 12/2009 of the german »Linux Magazin« features several GPS related articles. On page 40 there’s one about Openstreetmap on mobile devices, especially the N810.
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Unstructured points of interest – today’s catch

Thursday, October 29th, 2009

After an intense working day (we are doing some last-minute bugfixing to get interiorcad 2010 released) I needed something to relax and read the backlog of some mailing lists. This means I did what I do all day: processing information :) .

Here are some bits of stuff I preseved for later inspection.

openstreetmap

Engadget shares some videos concerning the new routing capabilities of Google Maps. A phantastic service, and I was immediately asked whether this will influence Openstreetmap. The answer clearly reads as »yes«. Some people who are interested in free routing will surely leave OSM and use this cool new Google service. But anyway, it won’t harm OSM much. Still Google Maps focusses a different audience than OSM does. And competition always is a good thing, as it cheers us to do better.

Some guys in the nederlands have created a service where you can export POIs from OSM data. Some time back I provided POIs extracted from OSM data by some home-grown C++ code. I’m glad that this is now available as a web service – much better for users than installing some weird command line app developed by an squirrel hacker like me.

I always wanted to write a tool which converts OSM data into some MIDI or audio data. But if you are too lame, chances are given that you are overhauled by someone else. So here it is, some Ruby code to convert OSM into MIDI data. Need to try this out »real soon now™«.

Some hiking map now allows to load, edit and save routes on top of OSM maps. Great service, while the inclusion of Google Sat imagery would be a great addition.

Sarah Hoffmann provides a map which renders hinking relations. It’s now available world wide and updated once a day. If you want your area to be renedered in a different style, write her an electronic message.

Nick Whitelegg updated Footnav, a 3D OSM visualisation tool aimed at countryside use.

The german newspaper »Die Zeit« shares an article concerning the history of the prime meridian.

Linux Audio

I’m using Linux for over 10 years now, and as a consequence I do all audio and MIDI processing on Linux boxes.

Rui released fussy doula of his famous Qtractor audio and MIDI sequencer. Highlights include audio send/return auxiliary inserts, mixer peak meters gradient eye-candy, MIDI System Exclusive setup manager etc. The recently added SysEx support means that my summer hack on Simple Sysexxer more or less was an unnecessary effort, except for the fact that I learned some more about C++ hacking :) . Nevertheless, Simple Sysexxer still is a famous tool to do mass backups of your synths.

Steve Harris released an update of Time Machine, now capable of automatically starting and stopping the recording after a certain treshhold has been passed.

There also was a release of Guitarix, a software guitar amp emulator. Need to build and try it out on weekend.

That’s it so far – time to go to bed. Another challenging and pleasing days of managing the release of some CAD/CAM software is ahead.

Fresh fungi catch – mapping hiking trails in autumn

Sunday, October 25th, 2009
Puffball

Puffball

Though it was cloudy at noon, it was a good decision to do some outdoor mapping. I grabbed some hiking trails around Langenberg. Here’s today’s tour:

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