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My new multilingual web application "Travel Info Pack" to view hotels, museums, supermarkets, cafes, etc. on the map prominently

Posted by Alex-7 on 22 December 2017 in English (English)

The web app is multilingual. The language selection is in the upper right part of the page.

Basically, you can view the same information at the, but to use the Travel Info Pack one does not have to know neither SQL, nor English, nor OSM tags.

The list with the OSM tags (key=value pairs) is searchable as one types, and it is with the tags's icons.

The web app memorizes the language choice, last location, and searched object. Each marker has got a link to view Wikimedia images with coordinates in the radius of 500 meters around the object.

Since the drop-down list is searchable, I can add much more OSM tags to it. It is what I plan to do.

Tool for measuring elevation above sea level on the OSM map

Posted by Alex-7 on 27 November 2017 in English (English)

I created a tool to calculate an elevation at the point of a click on the OSM map:

The elevation is calculated as an average from the values of the ele=* keys found around the click in the radius of 1 (or 2, or 3) kilometers.

I decided to write this simple application after I read an excellent article GPS Altitude vs Pressure Altitude.

For some areas of the world there is a lot of elevation data in the OSM database, and for some there is practically none. I think it is due to the misunderstanding about the difference between GPS Altitude and Pressure Altitude. The article makes it clear that both approaches are not perfect, but these are all what we've got, and we are to use one or another.

The application seems to be simple because all the heavy lifting is done by the Overpass API, OSM, and the Leaflet.

Elevation data could be useful for many purposes. For example, for planning a hiking or a cycling route, for planning a RPAS flight, for water management, etc. For example, if a hiking route starts at the altitude of 400 meters, and ends at 1600 meters, then it is immediately clear that it would be a hard day.

I also plan from now on to measure and add more ele=* data to the OSM.

Feedback and suggestions are very welcome.

Deep digital mapping

Posted by Alex-7 on 24 February 2017 in English (English)

Last weekend I went to map an archaeological site. I had read a couple of academic archeological papers on this excavation and knew the exact location of the site.

It is a Roman tiles, bricks and ceramic workshop near the town of Chancy which worked for eight hundred years, from 1st century BC till 7th century AD.

This archaeological site was excavated, and then it was covered with earth again for preservation. Still there are antique tiles everywhere around. At that epoch it was a hi-tech enterprise, a place where the Roman Empire was actually built. And it is not completely clear why it was closed after eight centuries of production (an interesting question for today's reality too).

As a result:

I convert video to the open WEBM format, which is accepted by Wikimedia, with the command line tool ffmpeg. Some quality is always lost in conversion, but so far it is the best variant:

ffmpeg -i source.mp4 -c:v libvpx -crf 4 -b:v 18M -c:a libvorbis destination.webm

I used a free music with Creative Commons license for the video. But it is also possible to play yourself and record any music of any composer who died more than 70 years ago. For example, for these two videos I asked my spouse to play and record the musical themes:

Battle of Morgarten

The town of Zug

The idea of deep digital mapping is that reaching a remote destination takes time and effort. So being physically at the location allows not only to map an object on the OSM map, but also to film it, to record first hand impressions, perhaps to do some investigative journalism for a Wikipedia article, and link all this to the OSM map.

I realize by now that recording and editing a video is even more difficult than making good photos. Recording a musical theme is a world in itself too. It turns out that a digital piano does not record a MP3 file, but MIDI file (musical instrument digital interface), which should be exported to a computer first and then converted to an audio file with a program like the Logic Pro X.

If you have ideas or information on developing deep digital mapping, please, let me know.

Location: Chemin de Fargout, Chancy, Geneva, 1284, Switzerland

Geolocations of Wikipedia articles on the OSM map

Posted by Alex-7 on 29 December 2015 in English (English)

I wrote a web-application to find Wikipedia articles geolocations on the OpenStreetMap

After the click on the map, it shows Wikipedia articles geolocations in the radius of ten kilometers around the click. A Wikipedia language can be changed by replacing the language code "en" for English, to "fr" for French, "de" for German, etc.

I wrote it mostly for myself (and actually use it), but it works for the whole world and for all Wikipedia languages. The number of articles is limited by 100.

The addressable map of Geneva, Switzerland, project

Posted by Alex-7 on 13 March 2013 in English (English)

Geneva is an international city. There are a lot of international organizations in the city: UN, UEFA, WTO, etc.

I am currently working on mapping Geneva with addresses. I use bicycle and OSMpad for iPhone 4S, and my own free time, mostly on Sundays.

If you want to join this project and do not know how then write me a message and I would provide some tips. To support the project visit my website

It would take about two years in my estimation to mark all house numbers in Geneva.

Location: Val d'Arve, Carouge (GE), Geneva, 1203, Switzerland