INTRODUCTION OF GEOMATIC

The term Geomatics is an acronym formed by “Geo” that means the Earth, while the term “matics” refers to the information. It defined as the science, art, and technology of determining the relative positions of points above, on, or beneath the earth’s surface, or establishing such points. (Ghilani and Wolf,2008)

Geomatics engineering is a modern discipline, which integrates acquisition, modelling, analysis, and management of spatially referenced data, i.e. data identified according to their locations. It uses terrestrial, marine, airborne, and satellite- based sensors to acquire spatial and other data. It normally transforms the spatially referenced data from different sources into common information systems. Geomatics is a new term that formerly known as surveying.

To prepare a topographical map. To prepare an engineering map To prepare a military map To prepare a contour map To prepare a geological map To prepare an archeological map. To prepare a cadastral map

Plane surveying Geodetic surveying The curvature of earth is not taken into consideration. Thus it is treats as a flat plane. The instrument is always leveled according to the center of the earth (gravity level/plumb bob). Only appropriate for smaller areas. (less than 250 km2) Geodetic surveying The curvature of the earth is taken into consideration. Used for the area exceeding the 250 km2 Used mostly for national mapping programs/national boundaries. Very precise surveys of great magnitude.

Preliminary survey Layout survey Control survey Data gathering Geospatial data – distances, position and angles Locate physical position- water boundaries, trees, roads, structure, property marker Determination of difference in elevation (vertical distance) Layout survey Marking on the ground – wood stakes, iron bars, concrete monuments, nails, spikes, etc… Property lines, engineering works (roads, pipelines, bridges) and construction surveying Control survey Use as reference both preliminary and layout survey. Horizontal and Vertical control (benchmarks)

The basic principle of surveying is to be able to work out the position of a point from some other point or points, positioning from the known features to the unknown ones.

Topographic surveys Preliminary survey-natural & manmade surface features of an area. Hydrographic surveys Preliminary survey-underwater features to surface control points (shorelines, marine features, water depth) Route surveys Preliminary, layout and control survey for narrow-long strip of land (highway, railroads, electric transmission lines, channel)

Property surveys Preliminary, layout and control survey involve in determine boundary location/laying out new property boundary Construction surveys Layout survey for engineering works Final (as-built) surveys Similar to preliminary survey Provide final record of constructed features has proceed according to design plan Aerial surveys Preliminary and final survey using aerial photography and imagery. Use of digital camera, lidar, radar

Commonly used in field surveying are: Total Station Level & Rod Theodolite Steel Tape

Global Positioning System (GPS) Navigation and identify the coordinate of certain location. Remote Sensing Technique Using satellite image Geographical Information System (GIS) Computer technology used GIS for data analysis, storage and updating the database.

Geographic reference Earth reference system – denoted by geographic lines of latitude and longitude Latitude - run east/west (parallel to equator) Longitude – run north/south converging at the pole Use in navigation and geodesy Grid reference Grid system for a states/province Ease of calculation (plane geometry) and availability datum for large area (thousand miles) Legal reference Township subdivide by section and ranges (lot) that unique numbered Vertical reference Can be reference to any datum. Datum most used are Mean Sea Level (MSL). MSL is assigned an elevation of 0 ft or 0 meter.