INTRODUCTION

The origin of topography comes from “topo” for “place” and graphic for “writing” its closely related to geology and surveying which are concerned with accurately the land surface. And it’s also closely tied to geography and mapping system the GIS,

Evaluation is the distinguishing factor for topography maps. In GIS, we use digital elevation model for terrain. Ten out of ten topography maps shows contour lines which are just lines of equal elevation. The narrow definition of topography is specific to the arrangement of land forms. 

But in a loader sense, it incorporates natural and artificial features. For example: 

Topography maps often tie in administrative boundaries, cities, hydrographic parks, transportation and buildings, contour lines (Iso-lines) connect points of equal elevation by reading contours. We interpret height slope and shape in topography maps.

If contours are close together the slop is steep. But when contours are spread apart the slope is more gradual. We use contours for mountains valleys and bathymetry. For example, Mount Fuji stands at 3,776 meter spacing each contour lines represents equal elevations. Almost at the place of mountain Fuji. It is a 3750 meter contour line. 

There is no “World Authority” in topography mapping instead each country set their mapping agency designs their own topography maps with a specific goal in mind. For example constructing a meal high way might drive a topographic ma to feature wood land cover, soil types or rock classification along the route, overtime topographic map series often het periodic updates, but the true is that they can be complex and take years to create. In the United States, the first USGS topographic map was surveyed in 1892. Since then, map revision have continued for over 125+ years. The USGS procedure topo maps at 1:250,000, 1:100,000, 1:63, 360, 000 and 1:24,000. The most common is the 7:5 minute quadrangle series where one inch in the map representing 24,000 inches on the ground.

Another good example of topographic map is the USGS topes fug of time and terrain this colorful map, its overlays topography (hill shade) with understanding rock formations. This helps unravel the geologic history of the continent such as mountain building events. 

Topography Application and Uses

Topography maps show how rivers flow, how high mountain rise and how steep valleys descend. They lay out the land such as in these examples.

Engineering use topographic maps to plan a road, construct a called tower or plan a hydro electric dam. 

Geologist Use Topography to Understand telboric activity . Land forms and where to dig a mine 

Hackers use topographic map to fund trials and steepness of slope to plan their ascent.

Astronomers study the topography outside earth like on the moon, mars or an as steroid climate scientist tie topography into climate models to recognize air and water-flow. As landscapes evolve and technology advances topographers face an uphill battle for accuracy and completeness

1.1 AIM OF THE STUDY

This study aims of carrying out a topographic survey of government technical college Idah Kogi State.

1.2 OBJECTIVE OF THE STUDIES

This study is out to archive the following objectives

i. Reconstitute a sight in synthesized image of the ground.

ii. Determine of trajectory of over flight of the ground. 

iii. Calculate surface or volumes. 

iv. Trace topographic profile.