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understanding coorinates


andyr354

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My gps is set to the default settings of DD.MMM ? I think (this all new to me). I went to the NGS website just to look around and see that it is not an option to use the format in their datasheet search it seems like.

 

Is there a way to convert the measurment? Would 30 59.242N 097 19.339 be????

 

Andy

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Um...

 

Not sure what you are asking.

 

DD.DDD is a format of decimal Degrees. Normally though you ahve more numbers after the decimal.

 

Latitude and Longitude is in Degree's (360 of them) Minutes (60) and Seconds (60) with the math similar to adding hours and minutes.

 

Geocaching.com uses DDD MM.MMM as it's standard. It's accurate to about 6'. Your GPS can be set to decimal degrees, decimal minutes (the DDD MM.MMM) or a few other formats.

 

You can convert between them by doing the math, but why? It's easier to just use the format that's used.

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Your GPS is probably set to DD MM.MMM (this is the default). It is the same format that geocaching uses. The NGS datasheets are in DD MM SS or DD MM SS.SSSSS format. There is no way to get NGS to convert it, you will have to do it manually. Divide SS (or SS.SSSSS) by 60 and add it to MM and round to three decimal positions to get MM.MMM. Then you will have DD MM.MMM as used by your GPS. Optionally, you can go into settings on your GPS and change it to DD MM SS and enter the coordinates exactly as found on the NGS site. But I usually figure the little bit of math is easier than fiddling with the GPS settings and then trying to remember to set it back so it matches the geocaching site.

 

As a further aside, figure out how to get your GPS to recieve waypoints, get EasyGPS and download benchmark waypoints directly from geocaching instead of entering them manually. The investment in time is well worth the speedy and accurate download of information once you make it work. Even better is to use the NGS datasheets, BMGPX and EasyGPS to download a whole county at a time.

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quote:
Originally posted by andyr354:

hmmm I am not shure myself.

My unit is set to DDD MM.MMM I guess

I was just wanting to find out what my home location would be in DD.MM.SS so I could search directly on ngs site.


In this case, take the decimal portion of the MM.MMM in your home coordinates (the part after the decimal) and multiply by 60. That will be SS.SSSSS. Then search on DD MM SS.SSSSS.

In your case (from your first post):

30 59.242 becomes 30 59 14.52 (.242 * 60)

97 19.339 becomes 97 19 20.34 (.339 * 60)

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quote:
Originally posted by RogBarn:

Even better is to use the NGS datasheets, BMGPX and EasyGPS to download a whole county at a time.


 

I'd have to become a paid member of Geocaching.com to get that, right? Also, does EasyGPS support the comments and all? I'd never find half of the things by GPS along.

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quote:
Originally posted by GeckoGeek:

quote:
Originally posted by RogBarn:

Even better is to use the NGS datasheets, BMGPX and EasyGPS to download a whole county at a time.


I'd have to become a paid member of Geocaching.com to get that, right? Also, does EasyGPS support the comments and all? I'd never find half of the things by GPS along.


Actually, the best benchmarking solution does not involve geocaching at all so there is no need to become a paid member (other than supporting the site). That said, let me say that the software solutions for benchmarking are not very good right now. Hopefully, someone will step in and help out. At any rate, this is what I do: Get the datasheets in zipped form from the yearly archived benchmark section of the NGS site. You will need the misc file that includes the list of counties to know what file number represents which county for your state. BMGPX, Watcher and EasyGPS are software programs that have been referenced around here, sorry but I don't have time right now to look up links. Maybe someone else can help. BMGPX will take datasheets and create a GPX file. Watcher can read and write GPX files but since it is designed for caches and not benchmarks, it is far from a good solution. However it can be used to zero in on a area of benchmarks to help make a smaller file. EasyGPS can read GPX files and can upload the waypoints to your GPS. There is some small bug somewhere and you will need to do a quick fix to some (all?) GPX files before trying to use EasyGPS to read them. I think ClayJar (maker of Watcher) has the details, I have to look it up every time I need to use it.

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