Astronomy in Geomatics

Astronomy is the study of everything in the universe beyond Earth’s atmosphere. That includes objects we can see with our naked eyes, like the Sun , the Moon , the planets, and the stars . It also includes objects we can only see with telescopes or other instruments, like faraway galaxies and tiny particles.

The science of field astronomy offers to surveyors @ geomatics engineers a means of determining the absolute location of any point or absolute location and direction of any line-on the surface of the earth, by making astronomical observations to celestial bodies. Traditionally, geomatics activities deal with determining precise azimuth, positioning and timing. The dependency on astronomical techniques for carrying out such practices has been well understood.

Astronomic azimuths are bearings, which are referenced to the true north direction whereas geodetic azimuths are those referenced to a grid north direction. The difference between these two directions can be expressed through the deflection of the vertical.

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Bincang Geodesi Demi Malaysia

Kumpulan Penyelidikan Inovasi Geomatik (GnG), Fakulti Alam Bina dan Ukur (FABU), Universiti Teknologi Malaysia (UTM) akan menganjurkan Program Bincang Geodesi Demi Malaysia bersama Bahagian Ukur Geodetik, Jabatan Ukur dan Pemetaan Malaysia (JUPEM). Sesi perbincangan ini merupakan satu platform jalinan kerjasama dan kolaborasi antara Program Geoinformasi, FABU, UTM dengan JUPEM bagi menyusun strategi untuk memantapkan bidang geodesi di Malaysia.

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Tidal Analysis & Predictions

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the  Earth and Moon orbiting one another. Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present.

Tides vary on timescales ranging from hours to years due to a number of factors, which determine the lunitidal interval. To make accurate records, tide gauge at fixed stations measure water level over time. Gauges ignore variations caused by waves with periods shorter than minutes. These data are compared to the reference (or datum) level usually called mean sea level.

Precise determination of a “mean sea level” is difficult because of the many factors that affect sea level. Instantaneous sea level varies quite a lot on several scales of time and space. This is because the sea is in constant motion, affected by the tides, wind, atmospheric pressure, local gravitational differences, temperature, salinity, etc. The easiest way this may be calculated is by selecting a location and calculating the mean sea level at that point and using it as a datum. For example, a period of 19 years of hourly level observations may be averaged and used to determine the mean sea level at some measurement point.

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