Topography of the area can be best exemplified using a topo map generated using a topographic survey. Topography encapsulates any information or feature that is seen on the earth surface. All natural, man-made, geomorphological features are captured during the capturing of features elevation for topographic survey.
Surveyor generally tends to draw an imaginary line of equi-elevations called as a Contour map. The contours of the contour map can be segregated as Index contours (Major contours) and Supplementary contours (Minor contours).
Few of the surveyors also showcase an intermediate contour generally called as intermediate contour. These three / two types of contours are visible on any of the topographic maps. The index contours are generally showcased using the thick and solid lines. The intermediate contours are showcased with the dotted lines and last but not the least supplementary or minor contours are showcased using the thin lines. The general color combination for showing the contours on a topographic map are using shades of brown color.
The topographic map is prepared by Establishing horizontal and vertical control that will serve as the framework of the survey, Determining enough horizontal location and elevation (usually called side shots) of ground points to provide enough data for plotting contours when the map is prepared, Locating natural and man-made features that may be required by the purpose of the survey, Computing distances, angles, and elevations.
Topographic maps showcases the natural and man-made features aligned with the bench marks and TBMs. These maps are widely used by Engineers, Architects, Foresters and Geologists. The design lay out of any building, roads, dams, pipelines, land scape, railway tracks cannot be started in absence of a topographic map of the concerned area. Hence it is a mandate that topographic maps are made during the planning stage of any project.
These maps are largely produced in United States by the United States Geological Survey (USGS). The general scale adopted by USGS is 1:24000 which means 1 inch= 2000 feets. With the advent of technology different methods have been evolved over a period of time starting from legacy Plain table survey, Aerial Photogrammetry, Transit-statia to the latest auto laser scanners and other advanced technical instruments