TheSwamp
CAD Forums => Vertically Challenged => Land Lubber / Geographically Positioned => Topic started by: BlackBox on November 08, 2012, 03:58:10 PM
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I am no surveyor.
I do not typically use any sort of Survey Database, however a user is working a specific contract where a survey database is being used, and a discrepancy has been identified yet the cause is not known.
The issue specifically, is that once the survey data has been imported, and points added to the drawing, that the points are not matching the source ASCII file's (PNEZD) Northing & Easting for that particular point number.
Another issue is that seemingly all spot checks show that the resultant points added to the drawing are the exact distance and angle removed from where they should be.
This suggests some sort of datum related issue, no?
To test, I asked the user to use the Insert tab, Points from File (InsertPoints Command) instead, and to compare that data to the source ASCII file (PNEZD). All is well; 100% accurate.
For now the work around is that all survey data will be brought in this way, but I need to better understand what is causing the issue in order to mitigate in the future... Any ideas?
TIA
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instrument settings
coordinate zone settings
- try setting these to NO Datum No Projection/or to same CS as the data is presented in
I woud like to see
A) the template the drawing is created from
B) the point data
C) information regarding CS the survey data is/was collected in
then I could run a test or two to determine source and solution to the issue
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I think you have a different coordinate settings for your Survey Database than your template settings. During import via Survey the coordinates from the file are translated from the Survey Database Settings into the template Settings.
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I think you have a different coordinate settings for your Survey Database than your template settings. During import via Survey the coordinates from the file are translated from the Survey Database Settings into the template Settings.
unless one sets units and zone to No Datum, No Projection prior to importing the survey data
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The first time I tested bringing points into Survey, I found a coordinate shift. As near as I figured, Survey defaults to US Survey Foot while the default Civil 3D templates are set to international feet.
Once I set my file to match survey, I was able to bring the points in and the coordinates held.
I cannot recall if I needed to empty the survey points and re-import, but I also believe that I have had issues after changing datums or units until I saved the file and switched to another and then came back.
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I thought there was a topic that covered this already...
my search criteira does not return that topic....