How to Add Coordinates to a Non-Georeferenced CAD File in eField

This tutorial explains how to use the Map Adjustment function in eField to add geographic coordinates to a CAD drawing that is not yet georeferenced.

The process uses two points visible in the CAD drawing. Each CAD point is matched with its correct northing and easting coordinates. eField then calculates the translation, rotation and scale required to adjust the drawing.

Quick summary #

1. Open Map adjustment in eField.
2. Select the CAD drawing.
3. Add the first CAD control point.
4. Enter the first point’s known coordinates.
5. Add a second CAD control point.
6. Enter the second point’s known coordinates.
7. Review the calculated adjustment values.
8. Apply the adjustment and check the updated CAD drawing.

What you need #

The video shows or confirms the following:

• An EFIX GNSS receiver and handheld controller.
• EFIX eField software.
• A CAD drawing without georeferencing.
• Known northing and easting coordinates for two points in the drawing.

The exact EFIX receiver model and the coordinate system being used are not shown clearly in the video.

Step 1: Open Map Adjustment #

Open eField and go to the main project tools screen.

Tap Map adjustment.

The Map adjustment page opens. In the video, the selected CAD file is:

Map adjustment.dwg

Step 2: Start adding control points #

Tap Add control points at the bottom of the screen.

The Add control point page opens. It contains two coordinate sections:

• Map point
• Known point

The Map point fields represent the coordinates currently used inside the CAD drawing. The Known point fields are where the correct geographic coordinates will be entered.

Step 3: Open the CAD drawing #

In the Map point section, tap the CAD selection icon in the upper-right corner.

The Map adjustment-CAD view opens.

The drawing contains two points with coordinates displayed beside them. The video uses these points to position the CAD drawing correctly.

Step 4: Select the first CAD point #

Tap the point-selection or capture icon on the left side of the CAD view.

Navigate to the first point in the drawing. The video selects an Endpoint using the on-screen snap cursor.

After the endpoint is highlighted, tap OK.

The selected CAD coordinates are added automatically as the first Map point:

• North: 3286452.672 m
• East: 608672.960 m

Step 5: Enter the first point’s known coordinates #

Under Known point, enter the correct geographic coordinates for the selected point:

• North: 3285155.451 m
• East: 610799.907 m

Tap OK & Next.

This saves the first control-point pair and returns to the CAD view so that a second point can be selected.

Step 6: Select the second CAD point #

In the CAD view, tap the point-selection icon again.

Navigate to the second point in the drawing. The video again uses the snap cursor to select an Endpoint.

When the second point is highlighted, tap OK.

The second Map point is added with these CAD coordinates:

• North: 3286347.801 m
• East: 608821.764 m

Step 7: Enter the second point’s known coordinates #

Under Known point, enter the correct coordinates for the second selected point:

• North: 3285050.580 m
• East: 610948.712 m

Tap OK.

eField uses the two point pairs to calculate the map adjustment.

Step 8: Review the calculated adjustment #

The Map adjustment results page displays the calculated movement, rotation and scale.

The video shows the following results:

Move #

• ΔN: -1313.904 m
• ΔE: 2134.614 m

Rotate #

• Rotation angle: 359:59:59.347

Scale #

• Scale: 1.0000045

These values are calculated automatically from the two control-point pairs.

Step 9: Apply the adjustment #

Tap OK at the bottom of the results page.

An Updating… message appears while eField applies the calculated adjustment to the CAD drawing.

When the update is complete, the software returns to the main project screen.

Step 10: Check the adjusted CAD drawing #

Open the CAD view again.

Tap one of the points used during the adjustment. The displayed geographic coordinates now match the coordinates entered for that point.

The video shows the adjusted point with coordinates including:

• North: 3285050.580
• East: 610948.712

This confirms that the CAD drawing has been aligned with the known coordinate system.

Result #

The CAD drawing is now georeferenced using two known control points.

eField has calculated and applied the required northing and easting movement, rotation and scale. Points in the drawing can now be viewed with their corresponding geographic coordinates.