Land surveying is part of a science of Geodesy. Measurement can be done in two ways, including measurement of horizontal and vertical measurements. Horizontal measurement point to obtain a relationship which is measured above the earth surface, while the perpendicular measurement to get a straight relationship between the measured points.

For extensive measurements can be done by polygons, which uses a measuring instrument Theodolit. Polygon is a series of long lines sequentially each direction has been determined in the field. There are two ways of measuring polygons, namely Polygon Polygon Closed and Open. In this practical method used is the closed method of measurement methods. Closed polygon is formed lines back to the starting point, thus forming polygon (closed mathematical and graphical).

After measurements are taken and the results obtained, to describe the details and contours that area, it can be realized or made in the map. The map is called map situation map atsu technical and usually on a scale of 1: 500 and 1:1000, which is a depiction of a single polygon Attai more.

The information can be obtained from a map can be divided into:

"Quantitative information is information relating to quantities such figures: azimuth, distance, coordinates, angle, height and other points.

"Qualitative information is information relating to the pictures detailed map. Detailed maps are divided up:

o Details of nature, among others: Slough, sea, river, forest, and others.

o Detail of man-made, including: Roads, Bridges, Channels, Building, and others.

The line joining places having the same altitude is the contour lines. The contour line is an imaginary line with prices rounded elevation, and contour of the adjacent interval. Usefulness of the map situation, among others:

a. As a base map for planning-planning civil projects, including irrigation channels, highways, spatial and other settlements.

b. To identify flood areas, for example in the project and other dams.