Offset methods for GPS measurement

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Offset methods for GPS measurement

Post by Cheng » Mon Nov 14, 2011 7:05 am

Hi All,

I am using FG2008. For GPS offset (especially distance Offset), I only found two ways in FG --- one is in the GPS measurement menu which asks for input of direction,horiz dist. and vert dist. But this is unpractical in most case in the field because it's hard to precisely determine the direction (Azimuth). The other way to do distance offset is under the survey method menu which called trilateration by using two known points to determine the expected unknown point. However, it's better to call this calculation tool rather than survey method (it's the same as the Offset Intersection under Calculations menu). I just wonder WHY we need to actually store 2 points first before calculating the expected point (the point is unaccessable and needs to be offset). I am not sure if this issue has be improved in the newer versions. If NOT, I would like to suggest as follows:

1) For Trilateration, measuring PT#1 and PT#2 (automaticlly stored in the memory, Don't need to actually store them), then manually input the distance from PT#1 to target pont and PT #2 to target point, derive the target point based on PT#1 and PT#2.

2) recommend the offset method used in TopSurv as an alternative option for distance offset. ( Similar as Station/Offset, i.e Start PT --- End PT ----(Distance)-- Target PT)


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Jason Poitras
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Re: Offset methods for GPS measurement

Post by Jason Poitras » Sun Nov 20, 2011 9:19 am

Hi Cheng - great request. Could you add it to the our forum instead so other people can vote and comment on your idea.
Jason Poitras
General Manager

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