forums.silverfrost.com

Konstantin8 · Joined: 07 Jun 2013 Posts: 9

Hello,
I have a question about reading binary files with Fortran.

I have a file with logged GPS observations.
File and format for first several data fields are attached:

https://yadi.sk/i/R5vTA80Je2CTg
https://yadi.sk/d/cM9NiQaCe2CTN

Could anybody write several words about how to correctly open and start read this file?
Unfortunately I have never dealt with binary. I'm not a programmer.

Thanks in advance!

[/img]

wahorger · Joined: 13 Oct 2014 Posts: 1217 Location: Morrison, CO, USA

The links you have included do not appear to work.

The effort required to read the data is relatively small once the file formats are fully understood. Some knowledge of the machine used to create the data is extremely helpful, as well as the floating point system used (if not one of the standards).

Also, it is not uncommon for some GPS devices to store the data in an arcane system (like only seconds of arc, not DD:MM:SS.SSSS or DDMMSS.ssss or decimal degrees, etc.).

Without the internal format, it is impossible to write the code!

JohnCampbell · Joined: 16 Feb 2006 Posts: 2554 Location: Sydney

Are you sure the GPS output is binary ?
I would expect it is text although the records may not be terminated as DOS format <cr><lf>.

I would open the file using access='TRANSPARENT' and review all characters in the file.
The following gives some idea of an approach:

brucebowler · Guest

What GPS unit? It certainly looks binary to me, but with knowing which brand of GPS it would be impossible to decode the file. Note that MOST GPS units that spit out binary spit out the data in a proprietary format. If you can get the GPS to spit out its data in NMEA format, it'll be a human readable text that is well documented.