Look at NGS toolkit page for code by BWRemondi if you understand C coding. He uses pointers extensively.

Calculator, FAQ, NGDC home page ?ÿ ?ÿ ?ÿ ?ÿ ?ÿ

Bad info in posting 4 March 2019. My previous post on an easy way to compute the GPS week was wrong.?ÿ Also, my statement that GPS time started 5 Janu...

Oh, GPS time started 5 Jan 1980. ?ÿ ?ÿ

Why do it the easy way ???? ? I subtract the start of GPS time and subtract it from the current doy and year. Multiply years by 52 divide diff in days...

As to Bill93ƒ??s question: After asking the question why one needs the day of year, you follow with the reason. Many GPS receivers label their files w...

FWIW, The NGS also provides some nice source code (in C) dealing with times and dates in GPS. See:?ÿAlso FORTRAN 77. A little more involved than merel...

I like?which is "Introduction to Geodetic Astronomy" by D.B. Thomson. Many interesting issues when dealing with Celestial and terrestrial systems. See...

As for the original question, how to enter coordinates into a piece of Linux software you have, I donƒ??t know how anyone other than the software deve...

While Mr. Hamiltonƒ??s approach has the virtue of being straightforward and logical, it relies on the assumption that an EGM96 height refers to the sa...

Original post inspired some review of EGM2008. References provided for those with an interest in the topic. BTW, some of the larger files on the NGA s...

You want to perform an EGM96 ?ÿto NAVD88 height conversion using VDATUM. ?ÿAs seen in one of the images below, it does not appear to be possible using...

Thanks for the correction. I envy Bill Cƒ??s acquaintance with one of the greats. I have known some really smart people and found most to be on the ni...

On the matter of the development of phase measurement, I always appreciated the work of Charles Counselman III and recommend the following short artic...

Given that the original poster expresses confusion about the difference between WGS and NAD83, I wonder how well he understands the various iterations...

I disagree that Astro and geodetic azimuths are equivalent. See below.