GPS coordinates...

[fmaster360]

So with the boat, I got a few papers with misc numbers marking fishing spots. Thing is, I don't know how to get these. I'd like to figure out how to transpose numbers so that I can use them in one format in Google Maps, and then use another format for GPS usage in the boat. The Navionics app I just download is pretty sweet, but it uses the standard 82° 47.735 stuff, and the coordinates I have are xx-xx-xxx and xx.xx.xx, also, I have Loran coordinates for the last ones, in the format of xxxxx.x, any help?

[fmaster360]

ok, so xx.xx.xxx is read 28° xx.xxx

Anything on the weird xx.xx.xx or the Loran?

[John Jones]

If you google "understanding gps coordinate formats" you will get about 8 million hits.  I suggest reading a few of them.  There are four "standard" formats but not everyone writes them down the same so it can get very confusing.  

Not being rude or short with you but it would take hours of typing to write what is already out there.

[fmaster360]

Thanks. I tried searching and I wasn't able to get anything on the xx.xx.xx and the Loran stuff. I'll try again later I guess.

[fmaster360]

Ahh, after messing around with the numbers and plotting, it looks like he just wrote them down funny. If I map xx.xx.xx as xx xx.xx0 N, I can get a solid value. As far as Loran, it doesn't seem that the numbers are convertible with accuracy good enough to fish off of.

[seabob4]

As far as converting LORAN TD's to lat/lon, this looks interesting...http://www.andren.com/

[wingtime]

Lat Lon numbers can be expressed in several formats.  The degrees North and the degrees West are usually the same its the matter of how the fractions of the degrees are computed.  Typically you see them in two main types.  The first is decimal fractions of each degree.  ie: 100th of a degree and decimal point.  The other main type (traditional) is in Minutes and Seconds.   So the fractions of a degree are expressed in minutes with each degree being divided into 60 minutes and the minutes are dived into seconds.  Those are easy to spot since your dealing with units of 60 and not 100's  ie  82 Degrees 45 minutes 28 seconds  etc. so you will not see a fraction of a degree higher than 59 minutes.

Did I confuse ya?

The conversion of Loran C numbers to lat lon is hit or miss.

[John Jones]

The Andren software that Bob linked is about as close as you will get converting Loran C to gps but it will still be off, sometimes 1/2 mile or more.  If you have just one number that you have exact locations in Loran and gps the software can make corrections and be pretty dang close in that one area.  Move 10 miles and you have to start all over again.  I had the Loran numbers for a spring offshore of Tarpon Springs.  I used conversion software and put the result in my gps.  We went out there and found it with Loran.  The gps was 0.7 miles off.  Too bad that one of the Changes that were forced on us after the last election was the shutdown of the Loran system.

I have about 1000 Loran C numbers from a retired FL west coast charter captain if someone wants them.  I'll make them a good deal.  

[pete]

I have found that when putting in coords and actually marking a spot that the unit is at are not the same.Most gps units have a function to convert tds to lat lon.But the units get you on the spots better if they are on them.I use numbers to get me in the area and then actually find the spot and save it to memory.

[fmaster360]

Cool guys. I appreciate the help. Most of these points are too far north for me... Trade...? J/K, but I would really like a decent spot to park, drink some beer, and catch a few fish for eating that isn't 15 miles off shore.