Question

Mention any two ‘Scanning Errors’ in GIS.

Hint:

Check maps for folds or dust before scanning to avoid distortion and noise.

Answer 1

In GIS, scanning errors occur during the process of converting hardcopy maps into digital raster images.
One common scanning error is geometric distortion, which happens when the scanner does not move uniformly or when the map is not placed flat.
This can cause features to appear stretched, compressed, or skewed, affecting spatial accuracy.
Another scanning error is noise and unwanted marks.
Dust, scratches, or stains on the map may be captured during scanning, creating unwanted speckles or lines in the digital image.
These errors can interfere with vectorization and interpretation, requiring additional cleaning and editing.
Careful scanning, calibration, and pre-cleaning maps help reduce such errors.