This is the process of detecting and correcting the errors introduced into data during the data capture process. Editing may be carried out in two modes:
- Batch mode;
1. Batch Mode
In this method, software is used to recognize and correct specific error condition in the whole dataset at ago e.g. find and correct all undershoots and overshoots. The main advantages of this mode are that errors of the sane type are corrected in bulk at speed and repeatedly. Batch programmes can also be left to run during slack period e.g at night.
2. Interactive Mode
This is a mode in which small portions of the digitized graphic are edited at a time by the issuance of appropriate edit commands.
The advantages of this mode are:
- It is the only way to correct error conditions that batch mode cannot handle
- Immediate verification of corrections
- Enables simultaneous digitizing and editing
The disadvantage is that it is very slow and repetitive.
Most modern GIS packages enable editing in both batch and interactive modes. A part from the graphics, attributes and relationships may also need editing.