Adafruit Ultimate GPS Parsing Example
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Adafruit Ultimate GPS Parsing Example

by jj7 on Tue Jan 22, 2013 6:12 pm

Hey everybody,
I am using the Adafruit Ultimate GPS with an Arduino Atmega 2560 and I am having trouble reading the parsed data output (The parsing.ino example). More specifically, the location is being formatted as XXXX.XXXX with an appended N, S, E or W. I know latitude and longitude should be values between -90 and 90 and -180 and 180 respectively.

I ran the LOCUS example and used the online parser at http://ladyada.net/products/ultimategps/ and it gave me the output I expected (when plotted in google maps). I noticed that the coordinates obtained from the online parser are similar to the coordinates in the form of XXXX.XXXX except that the decimal is shifted to the right by two. Coincidence? I am not sure so any guidance would be very much appreciated.

For example:
The data from the online parser gave me -76.74775847765905,39.260605723930084 (Longitude, Latitude)
The real time data parser gave me Location: 3915.6442N, 7644.8696W (Latitude, Longitude)

The North Latitude and East Longitude correspond to a positive number and South Latitude and West Longitude correspond to a negative number.
So the numbers are very similar if the second set both have their decimal points shifted to the left two digits but are very different when plotted on a map.

Thanks in advance,
Jeff
jj7
 
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Re: Adafruit Ultimate GPS Parsing Example

by Arctic_Eddie on Tue Jan 22, 2013 7:15 pm

The online parser is in degrees and fractions of a degree. The real time parser is in degrees, minutes and fractions thereof after shifting the decimal point two positions to the left. This is the NMEA sentence. See table 2 on page 19 for data format details.

http://www.adafruit.com/datasheets/Glob ... et-V0A.pdf
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Re: Adafruit Ultimate GPS Parsing Example

by jj7 on Tue Jan 22, 2013 7:55 pm

Hey,
Thanks for the quick response, that makes sense and I have finally figured it out. Thanks again for your help.
Cheers!
-Jeff
jj7
 
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Joined: Thu Jan 17, 2013 1:48 pm

Re: Adafruit Ultimate GPS Parsing Example

by Arctic_Eddie on Tue Jan 22, 2013 8:40 pm

No problem, glad to help.
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