Topic: Import WGS Coordinates?

[therock003]

I have some coordinates stored in northing easting on decimal degrees format.

How can i import them on Autocad and proceed to calculate distances and stuff that i need to deal with?

Coordinates are gathered from handheld Garmnin GPS receiver and i assume the Projection System is WGGS84.

[dfarris75]

Do you have a civil package (ie - Civil 3d or Land Desktop)?

[therock003]

Yes i do, Civil 3d 2008.

[dfarris75]

Check out Mike's surface creation tutorial. I think he covers it there.
Also see my youtube videos where you can find one on importing points.

[therock003]

Well actually i do know how to import points but not when the northing easting is on degrees (geodetic format) rather than meters.

[mjfarrell]

set up you drawing beginning with the ACADISO.DWT, this template is set up on meters

Then adjust the drawing settings to use the proper Coordinate system, and then import your points.

You may want or need to set up a new point file format prior to importing them.

[Bob Wahr]

If all else fails, convert them with Corpscon before importing.

[sinc]

Like Mike says, you'll need a new Point format.  Right-Click on Point File Formats and create a new one.

Then create columns that match the data in your file.  I think the ones in the image below are decimal Lat and Long.

[mjfarrell]

And to add to SINC's diagram, after setting up the point format, use the LOAD button to load the file; and then the PARSE button next to the to test the newly created format prior to importing the points using the format to verify that everything is OK.

[Swift]

If you have it in a text file of some kind, Bob is right, Corpscon rocks.

[therock003]

Like Mike says, you'll need a new Point format.  Right-Click on Point File Formats and create a new one.

Then create columns that match the data in your file.  I think the ones in the image below are decimal Lat and Long.

Thanx i'll try that.

BTW guys concerning this corpscon tool,i cnat seem to download this from the site due to some javascript going wrong. http://crunch.tec.army.mil/software/corpscon/corpscon.html

Anybody have a direct link to the last version 6 in order for me to check this out as well?

[therock003]

One last question.

On the coordinate zone transform you select th zone the points are in and based on the zone the file is in the conversion is going to be made accordignly?

Cause i select WGS84 and i had set the drawing as Hellenic Geodetic Refernce 87 but the resulted georeference wasnt correct. The coords looked like they came from an arbitrary system and they weren't anywhere near where they should be based on the calculation i made from a coordinate transfarmation application.

[mjfarrell]

The coordinate transformation during the import points 'only' happens IF the data (point file) contains information specifying it's coordinate system.
Then on import the points will be transformed to the drawings current CS.

This would be REAL easy if autodesk would FIX MAP so that one could actually query C3D point objects.

You would set up a the drawing on the Point Data CS.
You would set up another file on the desired CS.
You would query the Data from the first file into the second and MAP would correctly convert the data from one CS to the other.


Use this tab to transform the coordinate system specified on the Units And Zone tab to local specifications.

Zone Description
Displays the description of the zone that is selected on the Units And Zone tab.

Apply Transform Settings
Specifies whether to apply the settings for coordinate system zone transformation. Selecting this check box enables all the other settings in the dialog box. You cannot select this check box if a zone is not specified on the Units and Zone tab.

To use the Transformation Tab of the Drawing Settings:
Using the Transformation tab of the Drawing Settings dialog box, you can relate the local northing and local easting coordinates of your drawing to the grid northing and grid easting coordinates for the current zone.

The zone transformation settings do the following:

Relate local coordinates to grid coordinates by transforming distances measured on the Earth (or geoid) to distances on an ellipsoid.
Relate distances on the ellipsoid to the flat plane (projection) of the current zone’s grid coordinate system.
These transformations are accomplished through the use of scaling factors. First, a sea level scale factor is applied to the local values measured on the geoid, and then a grid scale factor is applied, which relates the ellipsoid values to the grid projection. The scaling factors can be defined in two ways:

The sea level scale factor relates the distances on the geoid to the distances on the ellipsoid.
The grid scale factor relates the distances on the ellipsoid to the distances on the grid projection.
You must also specify reference points in establishing transformation settings.

These reference points are the two points that tie the local and grid coordinates together. The reference points can be defined in two ways:

By the grid and local coordinates of two known reference points in your drawing.
By the grid and local coordinates of one known point and a known rotation to grid north.

[sinc]

Oooh, there's some nasty confusion ahead...

Note that Michael has now started talking about the Transformation Tab.  This can be used to convert between Northing/Easting and Grid Northing/Grid Easting INSIDE OF C3D.  When using this tab, you can see the result by looking at your points in Toolspace or Panorama, and you will see the effect on the "Grid Northing" and "Grid Easting" columns.  The Lat/Long values displayed in this table are calculated from the Grid Northing and Grid Easting for each point.

The transformation I was talking about earlier, the one in the Point File Format, is used by the Import/Export Points options.  This transformation is only applied while transferring points to/from C3D.

As one final point that has caused massive confusion for some, the conversion in the Point File Format only works on Grid Northing and Grid Easting.  So when you define the Point File Format, you should use the Grid Northing and Grid Easting tabs instead of the normal Northing and Easting tabs.  This shouldn't affect you if you are using Lat/Long instead, I don't think...

[mjfarrell]

Actually I talked about BOTH methods to be sure to insure a lack of TOTAL confusion!