II. BASIC TEORYII.1 REMOTE SENSINGRemote Sensing is the art, science, and technology of obtaining reliable information about physical objects and the environment, through the process of recording, measuring and interpreting imagery and digital measuring and digital representations of energy patterns derived from noncontact sensor systems. (Cowell 1997). The remote sensing principle using waves of the electromagnetic spectrum. The energy radiates from an energy source. A passive (naturally available) energy source is the sun. An active energy source may be a lamp, a laser or a microwave transmitter with its antenna. The radiation propagates through a vacuum with the speed of light (c) at about 300.000 km/second. It reaches an object, where it interacts with the matter of this object. Part of the energy is reected toward the sensor. At the sensor carried on a platform, the intensity of the incoming radiation is quantized and stored. The stored energy values are transformed into images, which may be subjected to image processing techniques before they are analysed to obtain object information.II.2 SOFTWARE OF REMOTE SENSINGII.1.1 ArcGISArcGIS is a software program, used to create, display and analyze geospatial data, developed by Environmental Systems Research Institute (ESRI) of Redlands, California. ArcGIS consists of three components: ArcCatalog, ArcMap and ArcToolbox. ArcCatalog is used for browsing for maps and spatial data, exploring spatial data, viewing and creating metadata, and managing spatial data. ArcMap is used for visualizing spatial data, performing spatial analysis, and creating maps to show the results of your work. ArcToolbox is an interface for accessing the data conversion and analysis function that come with ArcGIS. ArcGIS comes in three variants: ArcView, ArcEditor, or ArcInfo, which are the low end, middle and fully configured versions of the software. Any of these versions can be used for this exercise. ArcGIS is a geographic information system (GIS) for working with maps and geographic information. It is used for: creating and using maps; compiling geographic data; analyzing mapped information; sharing and discovering geographic information; using maps and geographic information in a range of applications; and managing geographic information in a database.II.1.2 ArcInfoArcInfo is a GIS software has been widely used by experts in the field of GIS. In principle this is very supportive in the creation and development of a map based on the principles of integrated mapping information. The principle of this map information can basically be divided into two (2) sections, namely: Spatial information, which describes the location and shape of the elements of geography and its relationship with other elements (these elements include; dot, line, and area / area). Descriptive information, relating to the geography elements (attributes map).II.1.3 ArcViewArcView is a GIS application developed by Esri.Inc who have the ability to view, create, organize and manipulate data in a spatial / geographic. Concepts used by acrview same as other GIS software is the application of layering that each layer is filled by a type layer. Layer types allowed are: Type Point / Point is used to determine the precise location of an object. By nature it has a central point only. Type Line / Line which is used to determine a road, river or boundaries. with nature has midpoint and length. Type Polygon / Area / Shape is used to determine the nature of the premises of a local state has a midpoint, circumference and area. Layer in ArcView also called Theme.II.3 GAS PIPELINE