GPS mark format help

[smiley_doobinator]

Hi Guys,

I am new to GPS and was wondering if anyone could answer a question for me about GPS mark formats. I have noticed looking at some marks available on the net the some have 3 numbers in the last lot of numbers eg 27.52.262 and some only have 2 eg 27.55.24. Should the last number when entering a mark with only 2 numbers be 0 or just no entered. Any help would be greatly appreciated.

[Simmo2]

Isn't it just degrees, minutes and seconds?
So a three digit is just another decimal place, therefore somewhat more accurate.
i.e. 16.45.426 or 16.45.43 (rounded off?)

[tunaticer]

Its dependant on the format. It could be "slang" writing of one of two forms i know of. It could be DD MM.mmm or it could be DD MM SSS as both ways do not have a decimal point between the degrees and the minute areas. Therefore I do not trust the marks are written correctly. As for the number of decimal places in the last section, it denotes how accurate the reading is i.e. 4 decimal places is more accurate than 2. Depending on the target reef and the error in the satelite system at the time of arrival 2 decimal places could well be close enough.

Jack.

[SatNav]

eg 27.55.24

1. From the example it is not possible to determine with any certainty

2. A Lat/Long position written like that (multiple decimal points) is something invented by slack computer people and has no relevence in navigation terms

3. The number of decimal points relates to precision not how accurate the position might be. Precision and accuracy have a relationship but are not the same.