A planimeter is a mechanical measuring instrument that is used to measure the area of a two-dimensional shape on a map or drawing. It is often used in fields such as cartography, engineering, and architecture.

Option 1: To know the surface area on a map - This is the correct option. A planimeter is specifically designed to measure the surface area of a shape on a map or drawing. It does this by tracing the outline of the shape with a mechanical arm, which then calculates the area based on the movement of the arm.

Option 2: To know the distance on a map - This option is incorrect. A planimeter is not used to measure distances on a map. For measuring distances, other tools such as a ruler or a scale are used.

Option 3: To know the direction on a map - This option is incorrect. A planimeter does not provide information about the direction on a map. Tools such as a compass or a protractor are used to determine direction.

Option 4: To know the height of places on a map - This option is incorrect. A planimeter is not used for measuring the height of places on a map. Elevation information is typically represented on a map using contour lines or specific symbols.