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I have been given a list of locations within Denmark. Most of the are in decimal degrees. However, some of the positions are in different formats and I can't figure them out. Does anyone recognize these or have a guess as to what they might be?

I have some that look like this:

lat: 55,800,643,991,678,900 lon: 12,297,413,013,875,400
lat: 55,804,257,011,041,000 lon: 1,229,334,301,315,240
lat: 55,807,527,964,934,700 lon: 12,333,790,976,554,100

and some that look like this:

lat: 583625 lon: 6236347
lat: 583722 lon: 6236625
lat: 562843 lon: 6218293
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initially I was thinking 3d with some elevation pairs. But all of a sudden maybe just incorrect formatting on a long numeric. – Brad Nesom Oct 14 '11 at 21:14

You can experiment with different transformations on a Danish Ministry of the Environment site. You may have to make multiple guesses (narrowed down perhaps by this experimentation), map out the points, overlay them on related layers, and check for reasonableness.

The second set is likely in meters in UTM 32N. "Lat" and "lon" are mixed up: they correspond to easting and northing, respectively.

The first set most likely is decimal degrees with commas arbitrarily placed; thus:

55,800,643,991,678,900 lon: 12,297,413,013,875,400 

is likely

55.8006439916789 N, 12.2974130138754 E.

(The value "1,229,334,301,315,240" could correspond to 12.2933430131524. The many digits (16-17) and terminal zeros in these numbers strongly suggest these were originally double precision floats; the commas are likely the result of bad formatting.)

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The second set looks like UTM in easting,northing order, possibly zone 32 North. They don't match any of the ETRS89 DKTM zones or other Danish systems that I know about.

The first set could be decimal degrees (latitude 55.8, longitude 12.3), except for the 2nd longitude value. That one just looks wrong or misformatted.

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I think whuber is right, stripping out the commas from the first three coordinates and inserting a decimal point after the second digit yields:

55.800643991678900N, 12.297413013875400E
55.804257011041000N, 12.29334301315240E
55.807527964934700N, 12.333790976554100E

And transforming the second set of coordinates from UTM 32N (EPSG:32632) to lat/long (EPSG:4326), using gdaltransform -s_srs EPSG:32632 -t_srs EPSG:4326 gives us:

56.2645828314934N, 10.350121642421E
56.267062756001N, 10.3517752624261E
56.1056031447623N, 10.0103956718451E

Copying them into Google Earth shows that they are all in Denmark at least! They mostly look like they're on land-parcel boundaries so I presume they're part of a polygon dataset.

The formatting of the first three say to me that someone has converted double-precision floats to decimal by multiplying by 10^17 for use on a system that doesn't support doubles, maybe a piece of survey kit, or some legacy computer system. This has then been brought into a spreadsheet that has kindly formatted the digits, and saved out by someone who doesn't know what the data is meant to represent, possibly by a non continental European judging by the commas which are normally decimal markers there. The second longitude does strike me as odd, but it could just be an error by the person who copied it into the spreadsheet.

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