Register

CARIS HPD Paper Chart Editor

CARIS HPD Product Editor

CARIS HPD Source Editor

CARIS S-57 Composer

CARIS Paper Chart Composer

Registration assigns georeferencing information to images or vector files by transforming an unregistered image to align to a registered one. This is done by selecting control points on the unregistered file and matching them to the corresponding locations on the registered file.

Registration of images and vector data follows the same process.

Related commands

Procedure

This example uses an unregistered raster file: a TIFF image. The procedure for other data types is similar.

1. Open the external file and select the layer.

2. Select the Register command.

The image becomes partially transparent.

First, resize or reposition the image to manoeuvre it closer to the area from which you want to gather control points

3. Do one of the following:

• Resize by dragging the edges of the image.

• Reposition by dragging within the image.

As necessary, alternate between the zoom and selection commands to move the image to the correct position.

Once the image is in position, define the control points.

4. Select the transformation type.

The minimum number of control points used to register a file depends on the transformation type.

Control points are pairs of points. The source point defines a location on the unregistered file. The target point defines the same location on the registered file.

Select the control points as follows.

5. Select the Add Control Points command.

First, identify a location that is easily recognizable on both files.

6. Click at that location on the image.

A yellow box is displayed at the source position.

7. Click on the same location on the registered file.

A yellow arrow is displayed at the target position. A line is stretched between the two. These two points define a single control point.

Control points are listed in the Registration Grid as they are added.

The process is displayed in the Registration Summary window.

8. Repeat adding points until all points are entered.

You can edit the control points as they are added. See Edit control points for details.

The screen should look something like this.

When all control points have been added:

9. Select the Apply command.

The results are displayed in the Output window. The Registration Grid and Registration Summary are closed.

Residual values reveal discrepancies in the control points and help identify points that are off-position. Residuals are shown as decimal degrees regardless of the settings in Options.

If the residual values within a column are similar then the target positions are fairly accurate. A wide difference between one or more values suggests that the registration is not accurate.

Edit control points

You can edit control points at any time during registration.

Edit the coordinates in the Registration Grid:

1. [Optional] Do one of the following:

• Click in the cell containing the coordinate value, type a new value and press <Enter>.

• Use the commands in the pop-up menu.

Edit using one of these keyboard commands:

Edit in the Display window:

1. Select a control point and move the source point, the target point, or both.

Registration using the Registration Grid

You can use the Registration Grid to enter or edit coordinates for the control points.

1. Click the Latitude Registered and Longitude Registered cells to highlight the values.

If you are using ground coordinates, the cells are called X Registered and Y Registered.

2. Type the new coordinate values and press Enter.

The arrow is centred on the coordinate values.