Sunday, March 28, 2010

Remote Sensing

Remote Sensing

Definition:Remote sensing (remote sensing) is a science, art and technique to obtain information about objects, areas and symptoms using a tool (sensor) without direct contact with objects, areas and symptoms.Various kinds of sensors:Based on its nature;⇒ natural sensor eye, ear, nose ...⇒ artificial sensor cameras, radar, sonar ...Based on the source of energy;a.⇒ active sensor - an energy source derived from the sensor itself / artificial energy.sensor is equipped with a transmitter and receiver reflection of electromagnetic wavesb. ⇒ passive sensors - a source of energy not derived from the sensor itself, a good energy to go natural (sun) or artificialsensor is only equipped with a receiver reflectance / emission of electromagnetic waves.Based on the recording process:a. ⇒ photography sensors - data recorded on the film emulsionchemically processedproduce photob. ⇒ electronic sensors - data recorded on magnetic tape in the form of electrical signalsprocessed electronicallyproduce good visual data / images or digital dataVarious kinds of data:⇒ be a number of digital dataVisual data / image is an image ⇒Various kinds of visual data ⇒ → aerial photo image photo⇒ Image nonfoto → display image on the monitorVarious kinds of image photo:Based on the vehicle used:⇒ aerial photographs produced from aircraftPhoto orbital / Satellite ⇒ generated from satelliteBased sonsornya:Single Photos ⇒ A region portrayed in a photographPhoto Plural ⇒ A region portrayed in some photographs# Multi-spectral ⇒ Some photos in the same area produced at the same time.# Multi temporal ⇒ Some photos in the area were produced at different times.# Multi-level ⇒ Some photos in the same region produced from different altitudes.Based on the electromagnetic spectrum:⇒ ultraviolet photo using ultraviolet spectrum (... → 0.29 μ)Photo Ortokromatik ⇒ ​​use a portion of the visible spectrum, the spectrum of blue to green part of the spectrum (0.4 → 0.5 μ)⇒ panchromatic photos using the visible spectrum (0.4 → 0.7 μ)Infrared Photos ⇒ use infrared spectrum (0.7 → 0.9 → 1.2 μ)Based on the color:The original color photo (true color)Photos pseudo color (false color) ⇒ ultraviolet images, infrared photo, black and white photos.Based on the axis of the camera:Vertical photo.Photo incline (slope> 30), comprising;# Photos somewhat skewed (low obligue) ⇒ Horizon looks at the photo# Photos highly skewed (high oblique) ⇒ The horizon is not visible in photoVarious kinds of image nonfoto:Berdasarkkan vehicle used;Aerospace imagery (airborne image) ⇒ generated from aircraftSatellite imagery (satellite / Spaceborne image) generated from satellite ⇒Based on the sensor:Single imagePlural imageBased on the electromagnetic spectrum used;Thermal infrared image (3.5 → 5.5, 8 → 14 μ)Radar images and microwave images generated from pektrum ⇒ microwaveRadar imagery, including an active systemMicrowave imagery, including passive systems

The steps in obtaining geographical data from remote sensing:Detection; namely pennyadapan / observation data selectively on objects in the imageIdentification; the spelling of the characteristics of an object depicted in the images / aerial photographs.The main characteristics that can be identified from an object in the image there are 3, namely;Feature spektoral / spectral; the characteristics produced by the interaction between electromagnetic energy with the object. Cirri spektoral stated;Rona; the level of darkness and brightness of an object depicted in the images in the form of black / white. Rona is influenced by several factors, among others:Characteristics / properties of an objectWeatherLocationLeftMaterials used (film sensitivity)Emulsion processingColor; namely the form which appears in the eye by using a narrow spectrum of the visible spectrum.Spatial characteristics, ie the characteristics of an object associated with spatial problems, including;Shape; a framework of such objects, so many objects that are recognized Based on its shape.Example: * Street train elongated shape and more straight from the highway.* Shaped school building, I, L or USize; is characteristic of an object associated with distance, area, height, slope and volume. To mentukan sutu size objects depicted in those photographs are aerial photographs should be sought beforehand scale.
Scale =. f. → long-focus camerah → altitude of the plane of the object
Example: An object photographed from a height of 7500 m asl (above sea level). While the height of the object is 1,500 m above sea level. Camera focal length used was 20 cm.What is the scale of the resulting images from the photo shoot?Given:The focus of the camera used = 20 cmAircraft altitude (H) = 7500 m above sea level.Height of object (HO) = 1,500 m asl.So ketingggian plane of the object (h) = H - Ho= 7500 m - 1,500 m= 6,000 mAnswer: Scale = f: h= 20 cm: 20 cm ⇒ 6,000 m: 600 000 cm= 1: 30,000Note: Aerial photograph produced standard size is 23 X 23 cm, mean the actual area of ​​the photo shoot is = Area map X Skala2 = ...Texture; the frequency change of tone / color in the image. Or tinggkat roughness / smoothness of an object in the image (coarse, medium, fine)Pattern, ie the spatial arrangement that shows the characteristics of an object in the image.Patterns can be created by man or by nature. In general, the patterns created by humans can be distinguished from natural patterns.Example; perkenbunan more regular pattern compared with the pattern of the jungle.Site; as the location of an object to another object disekiarnya.Example: * mangrove forest / mangrove site on the beach / brackish water* Settlement population elongated shape in the vicinity of the site road / river / coastAssociation; That linkage between one object with another object.Coontoh; * The railway station is associated with a rail of more than one.* The school building associated with sports field.Shadow; can be used to determine the direction of the wind and clarify the appearance of an object or even mask the appearance of an object as it is covered in shadow.

Temporal characteristics, namely characteristics of an object depicted in the image on the basis of age / time of an object at the time of the perekamanan.Example: * Plant cane and maize are difficult to distinguish at the age of 1 month, but will be easily distinguished if aged more than 2.5 months.* River in the image appear dark in the dry season (because the water is clear) and appears brighter in the rainy season (because the water is turbid so that more reflects the light.)Introduction: the stage of collecting the types of objects are drawn on the basis of the same characteristics.Analysis: the separation of the border demarcation (delineation) group of objects that have the same form. Aims to group objects that have similar characteristics.Deduction: namely the existence of certain relationships in an object by using the principle of convergence of evidence.Convergence proof is to use some elements of image interpretation so that narrowing the scope towards a particular conclusion.Classification; merupakaan efforts to develop and describe an object that has been systematically analyzed.Idealization: the presentation of the results of image interpretation in the form of maps.
Benefits of Remote SensingIn the field of Meteorology (METEOSAT, Tiros, NOAA):→ Observing climatic conditions of an area through state of the cloud observations and moisture content in air→ Assist weather analysis and forecasting (prediction) by determining the air-pressure areas and low ttingggi and local rain storms / cyclones.→ Observing System / wind patterns on Earth's surface→ Perform data modeling meteorology and climatology.In the Fields of Oceanography (Seasat):→ Observing the physical properties of the sea, such as surface temperatures and surface currents.→ Observing tides and sea waves (height, direction and frequency)→ Searching for upwelling (water from the ocean floor that rises to perrmukaan), Sinking (tengelam water) and surface temperature distribution→ To study changes in the beach, erosion and sedimentation (LANDSAT and SPOT)In the field of Hydrology (LANDSAT, ERS, SPOT)→ Alirran River Regional Monitoring (DAS) and river conservation.→ Mapping river and river sedimentation studies.→ Monitoring of the area and intensity of floods.In the field of Geology, Geodesy and Environment (LANDSAT, Geosat, NOAA):→ Conducting mapping the earth's surface.→ Determining the geological structure and rock types.→ To monitor the affected areas (forest fires), volcanic activity and the spread of dust vulkkanik.→ To monitor the distribution of natural resources such as forests (location, size, distribution and damage due to forest encroachment.)→ To monitor contamination / pollution either due to forest fires and oil spills on beaches.

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