Map Transform

Adjust the Map to the Background map

This command is active when a background map is displayed. If more than one background map is open a dialog box is displayed where you can choose the desired background map.

Choose this command to adjust the background map to the grid or to the part of the map you have already drawn. It is highly recommended to draw a precise grid on the draft map and then to use the crossing points of the grid for the adjustment (however, any points can be used for the adjustment). The grid button must be pressed to see the grid. You can use 1 to 12 points for the adjustment.

For each point you do the following:

1. Mark the grid point on the background map.
2. Mark the same grid point on the grid displayed on the screen.

When you have adjusted enough points, press the Enter key on the keyboard. The background map is rotated and stretched to get the best fit for the adjustment points. You can achieve a precise adjustment with 4 adjustment points arranged in a rectangle. This way you can compensate rotation and distortion. The horizontal and vertical scales will be adjusted individually.

Select Transform from Map menu:

• Move ADD
• Stretch / Shrink ADD
• Mirror ADD
• Rotate Map ADD
• Change coordinate System ADD

Affine

This function was called Transform Map before OCAD 10.2.3

Choose this command to adjust the whole map on background map or on grid. With this function you can geo-reference the map. The grid button must be pressed to see the grid. You can use 1 to 12 points for the adjustment. For each point you do the following:

1. Mark a point on map.
2. Mark the same grid point on reference (background map or grid.

When you have adjusted enough points, press the Enter key on the keyboard. The map is rotated and stretched (Affine transformation) to get the best fit for the adjustment points. You can achieve a precise adjustment with 4 adjustment points arranged in a rectangle. This way you can compensate rotation and distortion. The horizontal and vertical scales will be adjusted individually.

Rubbersheeting

ADD picture

This function is only available in OCAD 10.2.4 and later

Choose this command to adjust a part of the map on a geo-referenced background map. The Rubbersheeting Transformation dialog box appears.

1. Define rubbersheeting perimeter: Click the Define button and define the perimeter by drawing a polyline on the map. To define a new rubbersheeting perimeter click the Remove button to remove the actual one.
2. Add rubbersheeting points: Click the Add button first and then click 2x on the map for each point:

(1) Mark a point on the map.

(2) Mark the same point on the reference map. The rubbersheeting points are shown on the map by a red and a green cross and a connection line.

3. Calculate transformation: Calculate the rubbersheeting transformation: Click the Transform button.

-Click the Undo button if you are not satisfied with the rubbersheeting transformation.

-Uncheck rubbersheeting points in the Used column if they should not be included in the transformation. Unchecked rubbersheeting points appear in gray color on the map.

Center Map to Drawing Area

Choose Transform in Map menu - Center Map to Drawing Area.

This function is often used to center a map drawn in OCAD Professional edition into the smaller drawing area from OCAD Standard or CS edition. OCAD moves the map offset, all objects, all background maps and all bookmarks. After this function the map is still geo-referenced. In the dialog the extent with the existing map offset is shown in grey, the extent with the new offset in blue. The green rectangle shows the drawing area of OCAD Professional edition (80x80m), the orange the drawing area from Standard edition (4x4m). If a map should be visible in all OCAD editions then the entire map must fit in the 4x4m drawing area.