Connect your digitizing tablet and puck according to manufacturer's instructions.
Connect your digitizing tablet and puck according to the manufacturer's instructions and install the appropriate device driver.
Attach your paper map securely to the digitizing tablet. It is very important that the map not be moved during the digitizing session, or it will invalidate any control points you have established for the map.
Setting Up your Map on a Tablet
Make sure the map/drawing to be digitized is securely fastened to the tablet. If the map moves, control points will need to be reconfigured.
The box at the top of the Digitizer Setup dialog box displays a list of control points that you created. The box displays the X and Y coordinates for each point. The coordinates are displayed in the units set with the Map Units options on the Map Options dialog box (in the Layers window, right-click on the map name, and select Map Options).
The box also indicates the error for each point. The error is in paper units, which you specify in System Settings Preferences (on the PRO tab, click Options, and System Settings).
You need to specify at least four control points for MapInfo Pro to calculate error. When the error for a given point is too large, re-specify the point by clicking Edit or double-clicking on the control point.
The Digitizer Setup dialog box allows you to:
- Set the projection of the map being digitized.
- Set control points.
- Configure the Draw and Close buttons on the digitizer puck.
You should perform these steps in the order listed.
Digitizer Setup
To communicate the tracings on the paper map to MapInfo Pro properly, you must provide some information about your map. In the Digitizer Setup dialog box, you specify control points for your map, the map projection and appropriate map units, and configure the buttons on your digitizing puck. On the SPATIAL tab, in the Edit group, click Digitizer Setup to open the Digitizer Setup dialog box. Each part of the dialog box is discussed below.
Using Tools with the Digitizer
You can use any of these tools with the digitizer.
Mouse Cursor
You can use the mouse and the digitizer at the same time. The mouse is always active, even when digitizer mode is on. So you do not need to exit from digitizer mode to use the mouse. The mouse cursor is always visible, and is always controlled with the mouse. Its appearance depends on which tool is selected.
Digitizer Cursor
The digitizer cursor is a large cross hair that covers the entire width and height of the Map window. Its appearance does not change to indicate which tool is selected. It is always a large cross hair, making it easy to see. When digitizer mode is off, or when digitizer mode is on and a Map window is not active, the digitizer cursor does not appear.
The Status Bar only displays the digitizer cursor location if you choose to display it (on the lower-left corner of the MapInfo Pro screen, click the scale value to display a list of options, and then select Cursor Location).
If you choose to display the cursor, you will get some additional information. The cursor location is always displayed with the appropriate precision, depending on whether the location came from the mouse, the digitizer, or a snapped node. When you move the mouse, the displayed location is rounded to the nearest pixel. When you move the digitizer puck, the displayed location is rounded to the nearest tablet point. When you snap to a node, the displayed location shows the exact coordinates as they appear in the map file.
Map Projection
Maps are drawn using a particular projection, or distortion, of the earth's surface to maintain the relationship of the curved earth's features on a flat piece of paper. When you digitize a map using MapInfo Pro, you must specify the projection so that MapInfo Pro can take the map's distortion into consideration and maintain the correct relationship among the map features.
You cannot change the projection after you have begun to digitize, so make sure you set it correctly. Click Projection in the Digitizer Setup dialog box to select a projection. In general, the projection is specified in the map legend. MapInfo Pro supports a wide variety of projections. For aerial photographs, use Longitude/Latitude as the projection.
Map Units
In addition to knowing the projection, you must specify the map units used for the coordinate system. For instance, a map in the Longitude/Latitude projection will show map coordinates in degrees.
If you do not have coordinates for the map, you will need to digitize it as a non-earth map, which means points on the image will only be relative to each other, not to points on the earth. Create a non-earth map table first and display it in the active Map window.
Specify the map units from the Map Units drop-down list in the dialog box that matches the coordinate units on the paper map. Degrees will always be available for earth maps. In addition, other map units may be available if you have identified the map in a projection other than Longitude/Latitude.
Specifying Map Units
The Map Units drop-down list in the Digitizer Setup dialog box allows you to specify a value from a list of map units.
- Click the Map Units drop-down list. A list of units displays.
Degrees is always available for earth maps. Depending on the projection you are using, another unit, the native unit for that projection, may be available. When digitizing a non-earth map, you have a wider range of values.
- Choose the unit that matches the coordinate units on your paper map. When the desired unit is not in the list, check to make sure you specified the correct projection.