AN INSIGHT INTO REMOTE SENSING APPLICATION

posted Sep 13, 2014, 9:24 AM by National Association of Geography Students

Remote sensing is the examination or the gathering of information about a place from a distance. Such examination can occur with devices (e.g. cameras) based on the ground, and/or sensors or cameras based on ships, aircraft, satellites, or other spacecraft.

Digital sensors mounted on-board the remote sensing satellites scan vast areas of the earth’s surface during day and night and beam this data to the satellite ground stations for further processing and usage. With their continuous development and improvement, remote sensing satellites are increasingly being utilized for socio-economic development and national security.

Today, the data obtained is usually stored and manipulated using computers. The most common software used in remote sensing is ERDAS Imagine, ESRI, MapInfo, and ERMapper.

Remote sensing may be defined as the acquisition of information about an object or event on the basis of measurements taken at some distance from it. In practice the term is normally used to describe the collection and analysis of data made by instruments carried in or above the earth's atmosphere.

sensor is a device which detects and measures a physical parameter, such as radiation, and converts it into a form which can be stored or transmitted. In other words, it is the device which “sees” the objects or terrain towards which it is pointed. While devices which sense gravity, magnetic fields or sound waves can properly be classified as remote sensors, many authors restrict their use of the term remote sensing to describe measurements of electromagnetic radiation. That convention will be followed in this manual although a brief section is included on underwater acoustic devices such as sonars and echo sounders because of their importance to the fishing industries

Sensors may be classified according to a number of different criteria. For example, there are imaging and non-imaging sensors. As their name implies, imaging sensors produce a two-dimensional “picture” while non- imaging sensors produce point measurements or profiles. Sensors are also described as being either active or passive. Active sensors transmit radiation to “illuminate” the surface and to receive and measure the amount of radiation which is reflected back. Passive sensors, in contrast, measure naturally produced radiation which is either reflected solar energy or emitted terrestrial energy.

In order to provide a view of the earth's surface a sensor must be mounted on a platform which is simply the device or vehicle from which the sensor operates. Although stationary platforms, either attached or tethered to the ground, are sometimes used for specialized applications, aircraft and satellites are the most commonly used platforms for remote sensing. A general rule is that the higher the altitude of the platform, the larger the area that can be “seen” by the sensor; however, the ability to discriminate small objects will be reduced.

Data from sensors may be stored in analog or digital formats. In an analog system variations in the strength of the original input signal (e.g., the brightness variation in an image) are represented by continuous variations in some other medium such as voltage or film density. A digital representation, in contrast, divides the original signal into discrete ranges, each of which is assigned a numerical value. The range of the original signal as represented by a single numerical value is termed the radiometric resolution of the sensor system. Digitally recorded data, unlike analog data, can be processed easily by computers and can be copied repeatedly without negatively affecting the original or copied data. For human interpretation, however, an analog display such as a photograph or television picture is more useful. With appropriate equipment, it is possible to convert data from one format to the other.

Applications of Remote Sensing Technology

Who uses Remote Sensing and why?

-           The geographer, who looks for changes on the Earth's surface that need to be mapped;

-           The forester, who needs information about what type of trees are growing and if they have been affected by disease, fire or pollution;

-           The environmentalist, who wants to detect, identify and follow the movement of pollutants such as oil slicks on the ocean;

-           The geologist, who is interested in finding valuable minerals;

-           The farmer, who wants to keep an eye on how his crops are growing and if they've been affected by drought, floods, disease or pests;

-           The ship captain, who needs to find the best route through the northern ice packs;

-           The firefighter, who sends out his crews based on information about the size and movement of a forest fire; and

-           Many more.

Some of the areas in which remote sensing technology has been applied with varying degree of impact in many regions of the world are as follows:

• Agriculture

• Disaster Monitoring and Mitigation

• Climate Change

• Surveying and Urban Planning

• Water Resource Management

• Environmental Monitoring

• National Spatial Data Infrastructure

• Infrastructure Development Planning and Monitoring

• Mineral Exploration

• Telecommunication

• Coastal Eco-System Monitoring

• Defence/Geointelligence

JOB OPPORTUNITIES

Aerial Photographer - Takes segmented photographs of the Earth and other subject material from an aircraft. The photos are generally used for surveying or mapping purposes.

Aerospace Engineer - Responsible for the creation of airplanes or spacecrafts. They design, develop and test the aircrafts or spacecrafts using computer-aided design (CAD) software, robotics and lasers. They often specialize in one area of aviation.

GIS Analyst - This position creates graphic representations of physical land areas for analysis purposes. They are usually required to know many ArcView Softwares as well as Java-Script and HTML. Many analysts also focus on software building for the production of complex maps and reports.

Geophysist - This position specializes in areas like seismology or magnetic geophysics. Seismologist interpret data from seismographs and other geophysical instruments for the purpose of detecting earthquakes and faults. Geomagnetists measure the Earth's magnetic field using measurements taken over centuries and devise theoretical models explaining the Earth's origin.

Photogrammetrist - This position measures and analyzes aerial photographs for the purpose of utilizing them to prepare maps and drawings. They concentrate on parcels of land that are otherwise difficult or expensive to survey another way.

Pilot - This position is almost self-explanatory, but specific demands for aerial photography pilots require at least 3500 hours of flying time, a FAA commercial license, instrument rating and second class physical.

Geospatial Marketing Director - This occupation directs and develops marketing campaigns usually covering a large territory, within the geospatial markets. They build awareness and generate sales of all geospatial products generally mapping software.

Image Processing Analyst - This position is responsible for analyzing spatial image data as well as implementing and managing image databases, maps and other related products.

Cartographer - This position is essentially a map maker however, they may also collect, analyze and interpret spatial data.

Geographic Information Technician - This position is responsible for preparing, revising and maintaining a variety of maps and mapping related records, documents and reports. The job entails interpretation of maps as well as manipulation and revision of spatial database records.

Surveying Technician - This position collects land information in the field utilizing survey instruments and the help of other specialists. Once the information is collected this person uses computer-aided design tools to make drafts that will later be integrated into GIS platforms.

Education - Professionals in the field can utilize their education and experience by becoming a college instructor and help continue the expansion of GIS uses.

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