Introduction to Digitizing

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Digitizing is the process of converting geographic features on a paper map into digital format. The x, y coordinates of point, line and polygon features are recorded and stored as the spatial data. The feature attributes are also recorded during the digitizing process. It is the most common and labor intensive method to create a spatial database. The method is used especially when existing maps are available as the source of data. Coordinates of point features, line features and polygon features are recorded by manually pointing or tracing, using a digitizer table and cursor. The cursor position is accurately measured, by the device in order to generate the coordinate data in digital form. Although digitizing is substituted by scanning, digitizing tablets are still used to convert existing maps and drawings into GIS. Digitizing tablets typically support E-Size and larger drawings, with 0.001-foot resolution, 0.001-foot repeatability and 0.005-foot accuracy. Remember that, digitizing contributes to error.

Step-1 Setting Up The Digitizer

Go to the Step by Step Animation. See the Step 1.

Click to view the animation of digitizing - Step 1.

Step-2 Preparation of the Map for Digitizing

Go to the Step by Step Animation. See the Step 2.

Click to view the animation of digitizing - Step 2.

Print this map for digitizing.

3. Create the Common TIC file

Go to the Step by Step Animation. See the Step 3.

Click to view the animation of digitizing - Step 3.

4. Register the control points

Go to the Step by Step Animation. See the Step 4.

Click to view the animation of digitizing - Step 4.

Click to view GUI for Control Point Register.

5. Digitizing Point Feature

Go to the Step by Step Animation. See the Step 5.

Click to view the animation of digitizing - Step 5.

6. Digitizing Line Feature

Go to the Step by Step Animation. See the Step 6, 7 and 8.

Click to view the animation of digitizing - Step 6, 7 and 8

7. Digitizing Polygon Features

Go to the Step by Step Animation. See the Step 9, 10 and 11.

Click to view the animation of digitizing - Step 9, 10 and 11

Step By Step Digitizing Animation

DigitizingAnimationText

Step By Step Digitizing Animation, press the Continue Button after reading the text

Digitizing Exercise

Set up the digitizer with digitizing software or GIS software available at your GeoInformatics Lab.
Print out the following map. Click to view the complete graphic. Then print the map.
Digitize the point features. The file name should be given as Settlements. Build the attribute table of settlements.
Digitize the line features that represent roads. The file name should be given as Road. Correct all the dangle errors. Build the attribute table of Roads.
Digitize the line features that represent streams. The file name should be given as Stream. Correct all the dangle errors. Build the attribute table of Streams.
Digitize the polygon features that represent different landuses. The file name should be given as Landuse. Correct all the dangle errors and label errors. Build the attribute Table of Landuse.