Cartographers represent geography in many ways. Maps are often described as being either large or small scale, depending on their level of detail. Large-scale maps represent an area in higher detail; thus, the map may be more detailed, but cover a smaller area.
Cartographers use scale to represent the level of detail in a map. It is a ratio level of measurement that indicates how a particular map unit (inch, centimeter, etc.) corresponds to a geographic measurement of distance (such as a mile, kilometer, meter, etc.). On a map drawn with a scale of 1:24,000, for example, 1 inch equals 24,000 inches "on the ground."
Ways of Representation
There are multiple methods of measuring a map. The most common include map ratio (1 inch equals 1 mile), scale bar (graphic line with tic marks) and relative ratio (1:24,000). Each of these methods depend on the purpose of the map and its potential for reproduction. For example, if you want to enlarge a map, you would use scale or relative ratio as the distance from point A to point B will remain constant.
Level of Detail
The level of detail in a large-scale map reveals more particularities of a given area. This is important when a higher precision level is required. For example, when looking at an urban environment, such as a street level or address level scene, issues such as center-line from the street or distance from one house to another may be more relevant at a scale of (in map ratio terms) 1 inch equals 100 feet than it does at 1 inch equals 5 miles. Thus, the purpose of the map will determine the level of detail.
To make a large-scale map, you can use satellite data (GPS points), surveys (obtained from your local municipal office or USGS), or a compass. Geologists, for example, have a surprisingly precise method of knowing the distance of each pace that they step, which enables them to estimate the distance from point Y to point Z. Many of the original surveys of the United States were performed using such a methodology. Coupled with a knowledge of surveying, this process provided a cartographic knowledge of the United States. Once you have this basic knowledge, creating a large scale map can be done.
Places to Contact
Your local USGS, library, office of urban planning or local hiking trail services have many large-scale maps. These organizations are helpful and knowledgeable in discerning what level of detail you are looking for.