Transform object Between Coordinate System

[Sgear]

Hi

this is how I can transform drawing Between Coordinate System see Attachment
https://goo.gl/NqAAKt

I ask this first in theswamp.org
https://goo.gl/hX5Fr4

is it poseble to loop over all object in open drawing and fransform Between Coordinate System

[fieldguy · Accepted solution]

this requires a vertical product like map 3d. check the geospatial platform dev guide

http://docs.autodesk.com/MAP/2014/ENU/Developer_Guides/index.html

[norman.yuan · Accepted solution]

It looks like you are talking about transformation between geographic coordinate system, be it between geodedic and projected, or between projected ones.

The simplest way is to use AutoCAD Map/Civil3D built-in approach. Assume you have a drawing with coorinates of one projection, you can do it in different ways (but since you are asking in programming forum, I assume you need to do it programmatically):

1. do it with Map's drawing set query, as your unfinished (not working?) project did;

2. use Map's platform API to calculate the tramsform matrix and move all the entities (this would be bad/tedius to do). 

3. You can export all entityes in one drawing to shape/SDF, and import he shape/SDF, and then import back into a drawing with the other projected coordinate system;

4. If you not only know the 2 projections' code, but also have the knowledge of how the 2 projections are defined in AutoCD Map/Civil (there origins and the origin's difference intermed of Northing/Easting, the difference of the angle of the Nortings...), you can easily move all entities in one cordinate system to the other.

If you use AutoCAD Map/Civil, I'd suggest you use Map's built-in approach, eiterh attaching drawing to query in the entities in other projection, or export/import. Both can be done with AutoCAD Map ObjectARC .NET API.

[Sgear]

Thanks

[Sgear]

Maybe to quick to close this

1. the attachment project works I can transformation between coordinate system no problem there

I tray to move point from one coordinate system to another it is a little difference

I can use attachment project but I just need to know 🙂

in the Picture attachment you can see the difference

1. Blue point I use attachment project

2. Read Point I use this code

         Dim editor As Editor = Application.DocumentManager.MdiActiveDocument.Editor
            Dim db As Database = Application.DocumentManager.MdiActiveDocument.Database
            Dim trans As Transaction = db.TransactionManager.StartTransaction()

            Dim factory As MgCoordinateSystemFactory = Nothing
            Dim catalog As MgCoordinateSystemCatalog = Nothing
            Dim coordDic As MgCoordinateSystemDictionary = Nothing

            factory = New MgCoordinateSystemFactory()

            catalog = factory.GetCatalog()
            coordDic = catalog.GetCoordinateSystemDictionary()

            Dim ISN93 As MgCoordinateSystem = coordDic.GetCoordinateSystem("ISN93")
            Dim ISN1900 As MgCoordinateSystem = coordDic.GetCoordinateSystem("Reykjavik.IcelandGrid")

            Dim coordSysFactory As New MgCoordinateSystemFactory()

            Try
                Dim selOpts As New PromptSelectionOptions()
                Dim res As PromptSelectionResult

                selOpts.SingleOnly = True
                selOpts.MessageForAdding = "Select an entity"
                res = editor.GetSelection(selOpts)
                If (res.Status <> PromptStatus.OK) Then
                    Return
                End If

                Dim id As ObjectId = res.Value.GetObjectIds(0)

                Dim ent As Entity = trans.GetObject(id, OpenMode.ForWrite, False)
                Dim mat As Matrix3d = ent.Ecs

                Dim ISN93ToISN1900 As MgCoordinateSystemTransform = factory.GetTransform(ISN93, ISN1900)


                If TypeOf ent Is DBPoint Then
                    Dim opt As DBPoint = TryCast(ent, DBPoint)
                    Dim ISN93ToISN1900Coord As MgCoordinate = ISN93ToISN1900.Transform(opt.Position.X, opt.Position.Y, opt.Position.Z)

                    editor.WriteMessage(opt.Position.X & "   " & opt.Position.Y & "   " & opt.Position.Z)

                    Dim moveVec As New Vector3d(ISN93ToISN1900Coord.X - opt.Position.X, ISN93ToISN1900Coord.Y - opt.Position.Y, ISN93ToISN1900Coord.Z - opt.Position.Z)
                    Dim moveMat As Matrix3d = Matrix3d.Displacement(moveVec)
                    ent.TransformBy(ent.Ecs.PostMultiplyBy(moveMat))

                    trans.Commit()

                End If

            Catch ex As System.Exception
                trans.Abort()
                MsgBox(ex.Message)
            Finally
                trans.Dispose()
            End Try

[fieldguy]

Is your data 3D (is your Z not zero)? That's just a guess... my transformations all use Point2D.  What is the distance between the 2 points? I don't believe "UNITS" should be an issue - @norman.yuan might provide more info...

[Sgear]

The data is 2D, Z is zero

the distance between the 2 point 0.024  not much but should not be

UNITS = Millimeters

[fieldguy]

try creating a new DBPoint instead of "moving" - just to rule that part out of the problem.

I am not good with vb syntax anymore.

Dim ISN93ToISN1900Coord As MgCoordinate = ISN93ToISN1900.Transform(opt.Position.X, opt.Position.Y, opt.Position.Z)

create a new point2d with ISN93ToISN1900Coord.X and ISN93ToISN1900Coord.Y.

place a new DBPoint at the new point2d

<edit> create a new Point3D with mgcoordinate.X, Y, Z.

create a new DBPoint at new Point3D 

[norman.yuan]

I am not sure where the difference bwtween using AutoCAD Map built-in command/operation and using Platform API's calculation was from, in your case.

I just did a quick verification, like this:

1. I have a shape file created in projected coordinate system "NAD83.BC/Abers", in which a point's coordinate is X=1233743.880, Y=1196519.261.

2 I want to convert this point into projected coordinate system "UTM83-10".

So, here is what I did in different ways and the results are all the same, the converted UTM83-10 coordinate is X=545837.500, Y=6173925.001. (well, both of the coordinate systems have unit in "METER", thus the converted number may have tiny difference in the 5th, or 6th decimal, which is ignorable):

1. I start a blank drawing, assign UTM83-10 coordinate system to the blank drawing. Then I use "MapImport" command to import the shape into the drawing. Then I checked the point's coordinate.

2. I start a blank drawing, assign it UTM83-10 coordinate system, drag the shape into the drawing, which is equivalent to use MaFDO connection to load FDO data into AutoCAD MAP. This also correctly convert the NAD83.BC/Abers coordinate into UTM83-10 coordinate, the same as 1.

3. I wrote code to programmatically convert the coordinate with Platform API, just as you did (with actually moving the DBPoint). the result is the same. here is the code anyway:

using System;
using Autodesk.AutoCAD.Geometry;
using OSGeo.MapGuide;

namespace MapPlatformCsTranform
{
    public class CoordConverter
    {
        public static void Convert(string fromCs, string toCs, Point2d fromPoint, out Point2d toPoint)
        {
            toPoint = Point2d.Origin;

            var factory = new MgCoordinateSystemFactory();
            var catalog = factory.GetCatalog();
            var coordDic = catalog.GetCoordinateSystemDictionary();

            MgCoordinateSystem  fromCoord = null;
            if (coordDic.Has(fromCs)) fromCoord = coordDic.GetCoordinateSystem(fromCs);
            if (fromCoord==null)
            {
                throw new InvalidOperationException(
                    $"Coordinate system {fromCs} is not available in AutoCAD Map.");
            }

            MgCoordinateSystem toCoord = null;
            if (coordDic.Has(toCs)) toCoord = coordDic.GetCoordinateSystem(toCs);
            if (toCoord == null)
            {
                throw new InvalidOperationException(
                    $"Coordinate system {toCs} is not available in AutoCAD Map.");
            }

            var coordTransform = factory.GetTransform(fromCoord, toCoord);
            var mgCoord = coordTransform.Transform(fromPoint.X, fromPoint.Y);

            toPoint = new Point2d(mgCoord.X, mgCoord.Y);
        }
    }
}

using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.Geometry;
using CadApp = Autodesk.AutoCAD.ApplicationServices.Application;

[assembly: CommandClass(typeof(MapPlatformCsTranform.MyCommands))]

namespace MapPlatformCsTranform
{
    public class MyCommands 
    {
        [CommandMethod("CalcCoord")]
        public static void RunDocCommand()
        {
            var dwg = CadApp.DocumentManager.MdiActiveDocument;
            var ed = dwg.Editor;

            try
            {
                string sourceCs = "NAD83.BC/Abers";
                string destiCs = "UTM83-10";
                var sourcePoint = new Point2d(1233743.880, 1196519.261);
                CoordConvertion(sourceCs, destiCs, sourcePoint);

                sourceCs = "UTM83-10";
                destiCs = "NAD83.BC/Abers";
                sourcePoint = new Point2d(545837.50, 6173925.001);
                CoordConvertion(sourceCs, destiCs, sourcePoint);

            }
            catch (System.Exception ex)
            {
                ed.WriteMessage("\nError: {0}", ex.Message);
                ed.WriteMessage("\n*Cancel*");
            }
            finally
            {
                Autodesk.AutoCAD.Internal.Utils.PostCommandPrompt();
            }
        }

        private static void CoordConvertion(string sourceCs, string destiCs, Point2d sourcePoint)
        {
            CoordConverter.Convert(sourceCs, destiCs, sourcePoint, out Point2d destiPoint);

            var msg = $"Output point: x={destiPoint.X}, y={destiPoint.Y}";
            CadApp.ShowAlertDialog(msg);
        }
    }
}

I did not try drawing set/attaching approach, but expect the result would be the same. So, whether you use AutoCAD built-in approaches, as I suggested in previous reply, or use AutoCAD platform API to calculate the coordinate, the result should be the same with negligible difference (because the numbers are float point numbers).

[Sgear]

Thanks

How do you convert out to VB.NET

CoordConverter.Convert(sourceCs, destiCs, sourcePoint, out Point2d destiPoint);