What's So Different Between Aerial Maps And Topographic Aerial Maps?
The difference between aerial maps and topographic maps is that topographic maps give more information how steep the land is while aerial maps give a fly-over view of the area and that is all.
It is easy to read a topographic aerial map. It has thin brown lines that represent contours or areas of the same height or elevation. To represent a valley or stream the lines form a 'V' and the point of the 'V' points uphill. The closer the contour lines the steeper the area in question. The contours form loops that at the middle indicate the top of a hill while on the outer indicates the lower side or downhill.
On topographic maps, blue represents a body of water; green represents vegetation, roads and highways by black and red. Red usually indicates a build up urban area and within which some landmark buildings or structures are deliberately indicated in black.
There are two types of topographic map models. The digital elevation model (DEM) is a contour based digital dataset of the topography of the whole earth or part of it. The pixels in the dataset are each given an elevation value.
The topological model on the other hand shows the spatial relationship between data. It deals with what is next to what, what contains what and what is near what. It can also calculate the volume and surface area of the concerned object.
Topographic maps are useful to us just like any other maps. Specifically they are an indispensable part of all earth sciences. Mining and construction planning on a large scale are both areas that will make use of topographic maps. They are also useful on a less serious level, like for hikers who need highly informative maps for their task. The will need to know how steep the slopes are or even which direction the rivers flow and if there are any rapids or falls and the like.