GPS Localization

Discussion of FieldGenius related issues and questions.

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GPS Localization

Postby surveyjoe » Thu Aug 24, 2006 10:12 am

Hi Guys.... Especially Jason,

If I import an existing ASCII point file into FG2006 and perform a GPS localization, am I correct if I localize on point 1, tap "calculate parameters", localize on point 2, tap "calculate parameters", localize on point 3, tap "calculate parameters", localize on point 4, tap "calculate parameters?

Once I localize on the 4 points and tap "calculate parameters", it seems to me that FG2006 (2.0.5) is aligning itself to my existing points. Is it proper to start storing GPS shots after calculating parameters and bypass the adjust points? (I am telling FG to not store points during the localization).

It is my understanding there is no need to "adjust points" if no GPS points were stored before localizing.

Is this correct?

Thanks

John Roberson
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Postby Jason Poitras » Thu Aug 24, 2006 5:41 pm

Hi John,

Yes you are absolutely correct. If you choose to not store any GPS points that are used for localization then there is no need to use the Adjust Points button.

The Adjust Points button is used when you need to calculate new positions for points that were located by GPS. For every point you measure with GPS, FieldGenius always stores the raw WGS84 geodetic position in the raw file as an EP record. What will happen is that FieldGenius will re-process the raw file and apply the transformation settings to the EP records it finds and computes new coordinates for the GPS points.

With this in mind, if we continue with your scenario and pretend that after you localize to 4 points you continue on and measure and store another 100 points. At this point, these 100 shots were transformed by the parameters computed when you localized to four points.

Now lets assume that at the end of the job you found one more control monument and you decide to include in the localization. So you add it to the control list and compute new transformation parameters. Now to adjust the points you already measured you can use the Adjust Points command.

I hope this helps.
Jason Poitras
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Postby surveyjoe » Fri Aug 25, 2006 6:42 pm

Thanks Jason.

I thought I was correct. Thank you for the confirmation.

If Ned Ferguson (and others) are reading this. Maybe this is the temporary solution to importing point files that contain 2000+ points.

Import the point file, localize without storing the localization points (FG2006 2.0.5 Beta A, B or C), tap on "calculate parameters", DO NOT ADJUST POINTS and then begin your GPS RTK surveying.

FG2006 2.0.5 does not require the localization points to be stored with seperate point numbers. Ya'll are gonna love the new version.

Thanks Jason.

John Roberson
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Postby Ned Ferguson » Wed Aug 30, 2006 5:33 pm

surveyjoe,
Thanks for pointing this out. I am looking forward to it.
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