Maps - Register

The Register dialog appears when choosing Register from a layer tab context menu. Right click on a layer tab in a map and then choose Register to open this dialog.

 

The Register dialog allows us to move and rescale this drawing to specify its geographic location. It is a manual operation that is rarely used. On occasion, after using automated georegistration the Registration dialog will be used to "nudge" an image into slightly different alignment to suite the user's taste.

 

See the Georegistration topic for easier methods of georegistering images and drawings. See the Manual Georegistration topic for discussion of manual georegistration issues, including the use of the Register dialog.

 

images\dlg_register.gif

 

(units box)

Choose the unit of measure. All "unprojected" maps are in Degrees, Arc Minutes or Arc Seconds. Most projected maps are in meters.

Local offset

Shifted version of the external coordinate system peculiar to this component. Specifies shift in X (longitude) and Y (latitude) direction in the given units.

Local scale

Scaled version of the external coordinate system peculiar to this component. Specifies scale factor to be applied to external coordinate system.

Preview

Show effect of changes in the map window.

 

Changing the Local scale settings changes the scale of the component to make it bigger or smaller. Changing the Local offset moves the component horizontally or vertically. With great patience and conceptual understanding it is possible to use the Register dialog to move and re-scale overhead view images so they are aligned to drawings in Orthographic projection. A much better idea is to use Georegistration tools to do the job automatically.

 

The Register dialog is used occasionally to create special effects or other expert purposes. The following example shows one possible usage.

 

Example: Create a "Drop Shadow"

 

We can give our drawing layers a sense of three dimensionality using the following procedure.

 

Step 1: Prepare a Map of Mexico

 

·      Import a drawing of Mexico. Apply a thematic format.

·      Right click on the drawing in the project pane and choose Copy.

·      Right click again in the project pane and choose Paste As - Drawing. This creates an exact copy of the drawing.

·      Format the copy so it is black in both foreground and background colors.

·      Create a map using mexico and the copy. Open the map.

 

images\sc_register_eg01.gif

 

The illustration shows the map window with the mexico layer above the copy.

 

images\sc_register_eg02.gif

 

If we double click on the mexico layer to turn it off we can see the copy underneath.

 

Step 2: Use the Register Dialog

 

images\sc_register_eg03.gif

 

Right click on the copy layer (the all-black copy of mexico) and choose Register. Check the Preview box so we can see the action of the dialog. Click on the up spin button on Local offset X. This moves the CopyOfmexico layer to the right.

 

images\sc_register_eg04.gif

 

Click on the up spin button on Local offset Y. This moves the CopyOfmexico layer down. The result is what appears to be a shadow below the mexico layer. When we are happy with the effect we click OK.

 

Variations

 

The effect shown above is exaggerated. Smaller offsets in Local offset usually look better.

 

images\sc_register_eg05.gif

 

As seen above, a smaller displacement provides a more credible effect.

 

images\sc_register_eg06.gif

 

Combine this technique with other effects. The illustration above was created by making two more copies of the mexico drawing and in both of them deleting all objects except the highlighted provinces. We see a map with four layers: the topmost two layers contain the two provinces with a "drop shadow." Below them is the mexico layer at a 60% Layer Opacity value.

 

See Also

 

Edit - Change Projection for more information on using offsets and their relationship to other projection parameters such as false easting and false northing.