FAQ

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Frequently asked questions

I am an OpenStreetMap mapper. How can I also map cell towers?

OpenCellID mainly collects MCC, MNC, LAC, and CID information combined with a GPS position.
In most cases, it is not possible to obtain this data by going to a cell tower for various reasons:

  • the cell tower might be on a rooftop which is not accessible
  • there is no sign at the base station indicating such information
  • there are many antennas all together and it is not possible to find out which antenna has which Cell ID

In addition, one of the basic rules of OSM is to map visible things. This is not the case here as MCC/MNC/LAC/CID are not visible in most cases.
Therefore, only a very small number of cell towers is currently mapped in OSM with MCC/MNC/LAC/CID tags.

The most effective way to contribute to OpenCellID is to use one of the smartphone applications listed here and to collect measurements while mapping something else.
The Keypad-Mapper 3, for example, has a built-in feature to record cell tower data while mapping house numbers / addresses.

What is a CLF format?

CLF files contain information about mobile network cells.
They were used in some Nokia mobile phones for logging cell data: Cell Id, LAC, MCC, MNC, location etc.
OpenCellID supports import of CLF files as a source of information about cells locations. During the upload of the data it can be defined, if the uploaded data is measurements or if the file contains precise information of cell tower positions which would then override the average of all GPS-positions of all measurements of a given cell.

The following versions are supported: 2.0, 2.1, and 3.0.

CLF version 2.0

Files have the following format:
CellId(hex.)+LAC(hex.)+MCC+MNC<TAB>data
(plus symbol means that values are not separated; <TAB> — tabulation character)
Example: 239731EF26202<TAB>City Square

CLF version 2.1

Files have the same format as in version 2.0 but CellId and LAC are stored as decimal values.

CLF version 3.0

This format uses more information about cells. It has the following format:
MCC+MNC;CellId;LAC;RNC;Latitude;Longitude;Ratio;Data;RFU
CellId and LAC can be decimal or hexadecimal.
Example:
26202;07812;03101;00000;45.894375;31.51312;0;City Square;0

LAC vs. RNC

One RNC can handle multiple LACs. RNC ID does not necessarily have a connection to LAC ID - it depends how the network is planned. For example you can find in the same RNC (12) LACs 33, 21 and 78 - no connection between them. No relative connection of RNC IDs and LAC. This is based on how to plan the network. LAC depends on paging. RNC ID is same as Site IDs. It only serves as identification.