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inverted points from total station-help


timurphy

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Hi im having a somewhat strange problem. Im running autocad 2004 and using total station to survey a building in plan. The data process from the survey appears to be fine but when i bring the points into cad the survey in mirrored/inverted but the two contral/station points are located in the right place.

 

For example.. in survey terms im setting up at a stn located to the west and backsigthting to a stn at the east. i then carry out a survey to the south of these two points. However when the points are processed and bought into cad the stns are located in the right place but the survey is inverted and located to the north of the station....

 

any suggestions what might be causing this problem would be much appreciated.

 

thanks

 

tim

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That would be my guess also, when you imported your points into C3D or however you did it, using a CSV file or whatever data of the points, ensure it follows the format, PNEZD not PENZD (or whatever your point data is recorded in, just confirm it's matching (CSV or point data to C3D input). That's the first thing I would check out.

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Yeah, survey data is 'normally' collected in PNEZD format.

 

What are you bring in the coords. with?

 

Could you please show where in the world you are based, or qualify your statement, because in the UK, survey data is 'normally' collected in PENZD format.

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Could you please show where in the world you are based, or qualify your statement, because in the UK, survey data is 'normally' collected in PENZD format.

United States

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Thank you very much :thumbsup:

 

I should have specified that. Sorry, sometimes I forget that not everyone uses American standards; especially our idiotic love for the Imperial System. :x

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Ok a answer maybe one of the traps to surveying is if you set up and start then flip the transit rather than turning 180 degs you will get a full mirror image of your job. its called face left face right

 

If you use autocad "mirror" I think twice once in x then y planes it fixes the job but check to known points.

 

If you have the intrument file data not xyz then you can depending on software you are using reverse the transit to be up versus down etc and get correct data it may at worst be 180 orinted but correct levels. I have fixed jobs were this has happened but you must be able to go back to the intrument data .

 

Just an out there try setting your UCS upside down then add points restore back to world ?

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Hi-all thanks for f.eedback

 

I don't think its the 'face left' problem and the horizontal angle appears to be correct.

 

Im using a terminal programme to transfer the points from a topcon total station then pasting to notepad to create a csv followed by an excel file. im then using 'abc cad' add on that lets me bring the excel file straight into cad. this is when the problem of the mirrored points is presented. Strangely however if i call the x co-ord y and the y co-ord x when i bring the points into cad the survey is processed the right way round but in the wrong place and the wrong orientation.

 

i just can't seem to identify the part of the process that is causing this problem, has anyone used abc cad before?

 

Tim

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If a survey is plotted with E and N in the wrong order, you will always get a plot that can be mirrored about a 45° line coming from 0,0. That is the maths of it.

WrongEN.jpg

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Other things to check:-

 

Were the Control Stations drawn in using the coordinates the correct way round?

 

Were the Control Stations entered into the total station with the coordinates the correct way round?

 

Was one Control Station picked up as a detail point from the other Control Station, and vice versa?

 

Once you know exactly what has happened, the survey points can be recalculated if necessary.

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As you are using a topcon instrument you do not need to download into excell just read the p,x,y,z output file straight in just check though thats its set to xyz and not yxz

 

Also what model topcon you can in a lot of the models export a dxf file to read into autocad the instrument does all the reductions etc (ex Topcon employee)

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