Topographical maps are those:

Topographical maps are a type of map that provides detailed information about the physical features of a specific area. They are used for a variety of purposes, including urban planning, engineering, resource management, and recreation. These maps are characterized by their representation of the three-dimensional features of the Earth's surface on a two-dimensional plane.

Answer Explanation:

D: Are based on actual survey of small area

Topographical maps are based on actual surveys conducted on the ground. These surveys involve the use of specialized instruments and techniques to accurately measure and record the features of the land. The resulting data is then used to create a detailed and accurate representation of the area on the map.

Explanation:

Topographical maps are created through a process called topographic surveying. This involves the use of surveying equipment such as theodolites, total stations, and GPS receivers to measure the elevation, slope, and shape of the land. Surveyors traverse the area on foot or using vehicles, collecting data at various points to create a comprehensive survey.

The collected data is then processed using specialized software to create a digital elevation model (DEM) of the area. This model represents the surface of the land as a grid of points, with each point having a specific elevation value. From the DEM, contours can be generated, which are lines that connect points of equal elevation. These contours provide a visual representation of the shape and relief of the land.

The topographical map is then created by overlaying the contours onto a base map, which includes other information such as roads, rivers, and landmarks. The map is typically presented with a scale and a legend that explains the symbols and colors used to represent different features.

Topographical maps are known for their level of detail and accuracy. They provide valuable information about the terrain, including the location and elevation of hills, valleys, rivers, and other physical features. This makes them essential tools for engineers, geologists, surveyors, and other professionals who require precise information about the land.

In summary, the correct answer to the question is D: Topographical maps are based on actual surveys of a small area. These maps provide detailed and accurate information about the physical features of the land and are created through a process of topographic surveying.