Hi everybody. If anyone would be so kind to comment, I have a question about some project info I'm reading in Pocket-3D. After completing a localization on our current job, I'm reading the project info as follows:
Control points: 11
Localization is used
Origin: N 946.414m, E 1049.575
Rotation: -0d03'10"
Scale: 1.00005991
Can someone explain what that rotation factor means? Thanks a lot.?ÿ
That is the angle from Geodetic North to your project north.
Thank you @leegreen . Is there a plus side to having these line up as close as possible? Aside from maybe making it easier to perform stake out procedures on site. I guess it is all dependent on how the data prep was set up before hand.?ÿ
as long as project coordinates are consistent they are gospel. Projects need to be built off of the system they were designed in. As long as it all is ??constructable?
I had to look this one up. According to the Autodesk Knowledge Network:
True North?ÿis the real-world north direction based on site conditions.
@field-dog and @tkc1;?ÿYour responses are at such a level that I don't know where to begin.?ÿ
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@tkc1: If the deflection angle was zero in your localization, then you are perfectly aligned with Geodetic North. This is a red flag, nobody is perfect. If you want to be on Geodetic North, then I suggest using a single point localization in Pocket3d.
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Field Dog: Don't believe everything you see on the internet, especially when you are using a CAD application as the source. This definition makes no sense at all when surveying the real world.
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On surveys, it is important to define the Basis of Bearings. It should be specific and so others can follow your footsteps..
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There is no "True" North. This is an ambiguous term, with no specified meaning. It often implies Astronomic or Geodetic North, which differs by the LaPlace correction.
Reproducible North can be:
Geodetic North
Astronomic North
Grid North
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North that is difficult to reproduce:
Assumed North
Project North
Magnetic North
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I'm not familiar with Pocket-3d so I did a quick search and came up with it being a machine control program.?ÿ
I'm guessing you located at least two points of existing control and the program did some calculations to arrive at this localization.?ÿ
It's always best if you can do a first principal review of the coordinates before accepting a localization.?ÿ
In other words does the geometry of the figure actually mesh with real world geometry, are the interior angles, distances and verticals correct?
So inverse between two coordinates using NE from the given coordinates, and then from an un-localized projection, finally inverse between the two pairs using their LAT, LONG values.
Look at the rotation and there is your answer. If you don't have a geodetic inverse program there are free ones available on the interweb.
@ leegreen
My use of the Autodesk definition is somewhat disjointed from the OP's question. I was just trying to get involved with the post and learn something.
