[time-nuts] Survey plot as art.

Mark Sims holrum at hotmail.com
Sun Jan 8 22:41:07 EST 2017

The Adafruit receiver outputs NMEA format data.  The lat/lon values are sent as dddmm.mm format (ddd=degrees, mm.mm=minutes)  This restricts the resolution of the values.  Some receivers and newer NMEA specs support more digits past the decimal point.   Receivers that support native binary formats that report lat/lon as 32-bit floats show similar quantization.

The Thunderbolt has a command for entering the receiver position,  but it uses 32-bit floats.  This restricts the accuracy that you can enter a position.  Lady Heather's precision survey routines can calculate a position to greater accuracy.  In order to save the high-accuracy calculated position it uses the rather nasty technique of doing single-point self-surveys until one happens to be within a foot or so of the calculated position.... that can take an indeterminate amount of time to happen, but eventually gets the job done.


> The Adafruit plot seems to have quantization.  Are the values being
"snapped" to a grid in any way?

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