Grid co-ordinates and Local co-ordinates

[Anonymous]

I do more survey work and I am attending uni. I have just completed an Asconstructed drawing using CivilCAD 3d from a .DXF of survey data. No points just block references, and objects. I have applied the grid it should be on and the transformation(rotation scale and reference point etc.

I have checked the grid easting and northings (by exploding the block references and exporting the points as a .csv with the grid easting and northing as the x and y co-ordinates) with the 4 permanent survey marks that were recorded as part of the survey and they all line up well as points.

So I am assuming the transformation worked. My issue is that I only see the local grid. when I query the objects, etc.

What I need to do is export all objects in the drawing with the Grid Easting and Northing as the x and y co-ordinates for the drawing. Or somehow swap the grid easting and northings with the primary easting and northings used for the drawing, so that when someone opens the drawing they see it is on the MGA56 grid and the co-ordinates match the location as you scroll around the drawing.

How do I do this?

I have looked on the internet and I see lots of ways to manipulate the cogo points and I could convert all the block references onto points export the grid co-ordinates and then re import them, But this would mean I would have to re-draw all my line work (hours of work) and I donb't get the same discriptive fields that were in the block to do it with, which makes it take even longer.

Would writing a macro that would switch the easting and northing with the grid Easting and Northing of all vertex's, block references,lables, objects, etc be an option?

[AllenJessup]

Hello and Welcome to the Forum.

Can you explain your workflow on "exploding the block references and exporting the points as a .csv with the grid easting and northing as the x and y co-ordinates". Are you converting the exploded blocks to Cogo Points?

What you need is to have Cogo Points and then create the correct Point File Format for the export.

Allen

[Anonymous]

I appologise I might be getting some terminology wrong I will try to correct it here.  I am only exploding to check that the points are where they should be. I can manipulate the points with no issues. I am having trouble with manipulating a transformation for all objects. My work flow with points would be as follows.

I explode the block reference then hide all the other details like point number, name, elevation leaving just the node.

I then convert all the nodes to autocad points (using the points dropdown tab), I hope my terminology is correct so far, as the name says I am just learning.

I then export all the points to a .csv file with the PNEZ catagories. I have made my own as you can do with point exports, which exports all the longs and lats as well as Grid east and grid north I then check this info against the correct coordinates or I can then import them again as cogo points at the grid northing and easting locations. It doesn't work to re-iport them into the original drawing as they fly off into no where as civ 3d takes the transformed grid co-ordinates to be the local nothing and easting not the grid northing and easting. 

now as the nodes and points have grid eastings and northings I am sure that all the objects in model space would have that info attached to them in some way? wouldn't they? How do I get that information from all objects in my model space, from lables to polylines, etc. Or is there a way to transform the whole drawing so it is visably represented at the grid co-ordinates not the local x and y co-ordinates. 

Basicly I need to transform an edited drawing that I have edited in an arbitary local x , y  and z system the drawing is 3 dimentional so has elevations, it has lables symbols, anotations, 3dpolylines, 2d poly lines, block references, etc in it. I have done all this work making it prety in the co-ordinate system used by the surveyor when the pickup was done. I now need to put it into the mga 56 grid. I have the reference marks rotations and scale that needs to be applied to EVERYTHING but after going to the drawing settings applying the correct map grid and datum then applying the transformation requirements. Everything is still represented with the arbitary x & Y co-ordinates but I know there is now grid co-ordinates there too and I need everything to be represented by the grid co-ordinates.

[dhenderhan]

Hello and to reiterate what Allen said, Welcome to the forum.

I'm not sure if I understand your question exactly, but I'll take a crack at it. Civil 3D (I believe) won't convert drawings from one coordinate system to another....per se. If you know the coordinate system your original data is in, you can set that coordinate system up in the drawing and then using the datum transformation settings, set it up to export data to any other coordinate system, but you cant just change coordinate systems and have the drawing convert everything (graphics such as lines, or anything else in the drawing to that system) I use separate software to do converting between systems, so I'm not that familiar with the system transformation capabilities. I believe you can also set up the transformation setting to know what system you data is in and convert it to the currently set drawing system. The only suggestion that I have would be to create a second drawing on the desired output coordinate system (MGA56), draw a line (3 dimensional) between two coordinates that you have in commmon in the first drawing (usually primary control points that you have coordinates on in the ending system) and insert the first drawing into it (without exploding it) and then translating, rotating, and scaling the block to two known points and exploding the block. As I said, I'm not an expert in the Civil3D capabilities for datum transformations, but hopefully this might help. Anyone else that might have a better idea, please feel free to correct me and I might learn something as well.

[AllenJessup]

@dhenderhan has it mostly right. Civil 3D can convert drawings between two defined systems using am Map Query. However this doesn't work if one of the systems is arbitrary and it doesn't work on Civil 3D objects. Coming from an arbitrary system using his suggestion of move, scale and rotate (or the Align command) is the best way to handle it. If you have a text file with points in it. You can use Notepad or Excel to eliminate the coordinate values you don't want and import the points from the edited file.

I'm still having trouble understanding some things like "I am only exploding to check that the points are where they should be. I can manipulate the points with no issues". Why do you need to explode the points to check their position? I think you'd be much better off if all your points were Civil 3D Cogo points.

Allen

[AllenJessup]

Here are a few links on the process. I'll try and post something of my own later.

http://knowledge.autodesk.com/support/autocad-civil-3d/troubleshooting/caas/sfdcarticles/sfdcarticle...

http://knowledge.autodesk.com/support/autocad-map-3d/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU...

http://thecadgeek.com/blog/2008/01/converting-a-drawings-coordinate-system/

http://help.autodesk.com/view/MAP/2015/ENU/?guid=GUID-291991BF-31F1-46F0-A9E1-72A29B8E8C54

Allen

[Anonymous]

OK that answers my question.. Civ Cad 3d won't do what I want, perse.

Regarding having to explode the points the survey I have recieved the software used to do the survey automaticly turns all the points and lines recorded during the course of the survey into a .DXF file. This turns all lines into 3d poly lines and all points become blocks containing all data attributed to that point, and the insertion point is the actual point location so when you explode those blocks you get left with nodes to represent the insertion point it is these nodes I then convet into autocad points to be exported.

The only way I could check the transformation was sucsessful was to view or check the grid co-ordinates not the local co-ordiates. And I havn't found a way to view / export the grid co-ordinates on anything other than a point, be it and autocad point or a cogo point.

I have to cut this short as I must return to work but I will check those threads out and post another comment soon.