Stefan, I have to work-out the license issue as you mentioned. I really started from the OSM one... even if I have seen all the discussions about it. I am ready to consider all the solutions to solve this license problem.
>So you get the confirmation that the opencellid data is also under cc-at-sa? >We did not found a concrete statement about it and Daniel already sent them a >mail to clarify it. When I started http://www.openBmap.org and until a few weeks ago, there was no mention about the data license on opencellid website. (and impossible to reach them...) The other projects mentioned on http://en.wikipedia.org/wiki/GSM_localization did not mention their license too. As the logo creative commons appears now on the opencellid website, I have decided to import their data in my database. I will still able to erase their data if needed... Anyway, it will help me to raise scalability issues and define if needed another design for the mapping manager database. > The maps looks already quite nice, even if Germany is not in the db yet. ;) Thanks! and please have a look at the following url for zones in Germany http://realtimeblog.free.fr/maps/with_google_earth.php?mcc=262&mnc=7&step=2 or http://realtimeblog.free.fr/cell_map.php?mcc=262&mnc=7&lac=&cellid=&display=Display (please zoom out on Google maps to see Germany coverage for O2 operator) > Do you merge not only the data but also the projects? Having them co-exists with > the same goal is kinda pointless. Because 1) the CC license seems "all new" to opencellid.org 2) the way to calculate cellular "average" position and attributes are not the same... 3) the signal strengths are not stored at opencellid.org side I 'll wait a little before considering a merge. > I like to have more data available. Can you give us some insight how big such > collections can grow. For example your current db size and the current number of > entries? I would like to have the option to have such a db on my SD card for > offline use and syncing when on wifi or similar. >From the information I have collected, there must be 50000 towers in France (spread on 550000 km2) and I evaluate from 4 to 8 cells per tower for one operator. It means from 200 000 to 400 000 entries in a database for one country (as large as France) for one operator (to have the full country in local SD database) For these 400 000 entries, you need to store mcc/mnc/lac/cid and two double for latitude and longitude (and perhaps other attributes such as max radius...) Probably you will not need the full country all the time on your SD card. We probably can design a way to sync the local openmoko database with the openbmap database... On LAC basis for instance... If you want to have a closer look at the current local database (I extracted the local database from the website), please look at http://realtimeblog.free.fr/latest/realtimeblog_23_12_2008.zip It is the SQL script containing all the cells (before opencellid merge) cell descriptions and the cell coordinates... regards, Nick
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