How is a map different from a sketch?
A map is a selective, symbolised, and generalised representation of the earth's surface drawn at a reduced scale. It is drawn using scale and projection so that each point on the paper corresponds to the actual ground position.
In contrast, a sketch is a simplified map drawn freehand. It is a network of lines and polygons without a scale. Therefore, a sketch fails to preserve the true scale or orientation.
The primary difference is that a map is a scientific representation based on scale, whereas a sketch is a rough drawing lacking these essentials.
Explanation
The textbook context explicitly distinguishes between the two by highlighting the necessity of scale. A map is defined by its ability to represent features at a reduced scale with accuracy regarding ground position. Conversely, the text defines a sketch as a 'simplified map drawn freehand' that lacks a scale ('without a scale') and consequently fails to preserve true scale or orientation. The answer synthesizes these definitions to contrast the scientific nature of a map against the approximate nature of a sketch.