Format of downloaded computed Cell Tower data?

[How to]
#1

A few weeks ago I downloaded the Cell Tower data for the UK (234.csv) and am trying to understand what it means.

Sorry if I have overlooked something but I cannot find a description of the downloaded data, i.e., the 14 column headers. I think I have worked out the first 9 of the 14, viz:

Radio, MCC, MNC, LAC, CID, RNC, Longitude, Latitude, Ratio

but have no idea what the remaining 5 are. Nor do I really understand what some of these first 9 represent, even if (?) I have got the names right!

In particular I am trying to compare the data in this download with the data available on cellmapper.net, and so far I am failing to find any correspondence.

For example, in the area where I live in West Wales there is an LTE tower at Tegryn, According to cellmapper.net, one of the cell IDs broadcast from this tower is described thus:

MCC / MNC / Region: 234 / 30 / 26030
Cell Identifier: 6107136
System Subtype: LTE
PCI: 220 (73/1)
EARFCN: 1617

Assuming that Region is the same as LAC in the opencellid download, then I find 5 rows matching LTE, 234, 30, 26030 with these values of CID, Longitude, Latitude:

5030926, -5.1772, 51.9401
4259852, -5.2086, 51.9237
5457420, -5.2234, 51.9208
5457422, -5.2692, 51.8823
5030924, -5.1791, 51.9466

Even though the Long/Lat are in roughly the right area of West Wales, none of the CID match that of ANY of the Cell IDs on the mast at Tegryn (which are 6107136 through 6107141 and 6107149 through 6107150). Moreover, on cellmapper.net I cannot find any tower which is broadcasting ANY of these 5 CIDs - although I must say that this operation is difficult because I cannot find any searchable data on cellmapper.net, one just has to click on each cell tower individually and scroll though the list of cells being broadcast from that tower. So I might have missed one. But missed all 5? Surely not!

Can anyone tell me if I am trying to do something sensible? And if so, why am I failing?

Thanks!

1 Like
#2

Hi John,

If you download the worldwide data cell_towers.csv.gz, then the first line of cell_towers.csv has some descriptions. For some reason (past human mistake?) the country exports don’t have the first line descriptions - and I guess we don’t want to add them now, because it would upset any import automation that people may already have set up.

Also see Wiki > “Database” > “Download database” (the wiki page web address contains “Menu_map_view”; the forum doesn’t allow me to post links…).

Now, may I ask you about this Wiki page and your descriptions:

  • Wiki calls the 4th field: LAC/TAC/NID - Location Area Code. What is that?
  • Beware that it is out of date, and also less descriptive?. Especially
    • it’s missing a field/description for CSV 6th field “unit”, which you call “RNC”. What is that?
  • “Longitude” twice - obvious mistake; the description is for “Latitude” and is OK.
#3

Wiki > FAQ mentions that one tower can have multiple cells, on average more than seven.

#4

Hi Peter
Thanks for your reply. Re your questions:

It appears to be a geographical area code but AFAICT each Radio/MCC/MNC tuple has its own set of LACs.

I don’t know! I think I got it from the Wiki FAQ description of CLF version 3.0 before I understood that this is not the format of the downloaded database cvs files.

#5

For some reason (past human mistake?) the country exports don’t have the first line descriptions - and I guess we don’t want to add them now, because it would upset any import automation that people may already have set up.

Exactly this! We’ll link to the docs on the download page in our next deployment.

We’ve updated the database description wiki as well, thanks for flagging it: Database format - OpenCellID wiki