Points can be uploaded from AutoCAD to GPS2CAD by following this procedure:

 

• Open the AutoCAD drawing, switch back to GPS2CAD
• Go to File/Import Points/ACAD Points

 

• Read the Import Information box, and click OK
• The following window appears:

 

 

• Enter the ZONE that the points are in. You must know this in advance in order to import the points. If you choose the wrong zone, the resulting Latitude/Longitude translation will be incorrect. 

 

      If you do not know what zone you are in, and the points are near to your current location, you may get the zone by setting your GPS to read out in the same UTM system, and checking the zone that is displayed - but only if the points are in the same zone that your GPS is in.

 

• Select the Grid to import the points into. If you choose the Route grid, you may need to add a route header (the dark blue grid line that has the name of the route). You can do this by clicking the Add Header button, and supplying the requested information

 

• You should be taken to the AutoCAD drawing with a selection cursor active
• Select the Lightweight Polyline, points, or blocks to upload. In the case of a polyline, it does not matter which end you select - the veritcies will be entered only one way.
• The points will be placed into the selected grid.

 

Note that it is important to understand the following :

 

1. If you select one of the UTM datums, you must supply the Zone that the points are plotted in. In order to make the correct coordinate calculation, GPS2CAD must know what Zone the ACAD coordinates refer to, and there is no information maintained in AutoCAD that can be used.

 

2. When uploading points from AutoCAD, you must select the SAME DATUM that they were originally plotted in. For example, you CAN'T DO THIS:

 

• Download points from GPS into a Grid with the project Datum set to UTM_NAD27
• Plot the points into AutoCAD. They will be plotted based on the coordinates shown on the grid and the Datum Selected when downloaded
• Upload the points from AutoCAD and SELECT A DIFFERENT DATUM THAN UTM_NAD27

 

Normally during a working session, this mistake would not be made. The real risk occurs when the drawing is saved, and then re-opened another time, with a new session of GPS2CAD running. There will be no indication in ACAD what datum the points are plotted in, and the DATUM running in GPS2CAD MAY HAVE CHANGED. If you try uploading the points from AutoCAD, the resulting Latitude/Longitude calculations WILL BE WRONG!