This section provides definitions of relevant technical terms and acronyms to assist users of the website to understand the content.
Glossary
Across track scanning – A sensor that uses an oscillating mirror system that moves back and forth across a satellite’s direction of travel, creating scan line strips that are contiguous or that overlap slightly, thereby producing an image.
Active Sensors – A remote sensing system that transmits its own electromagnetic energy at an object(s) and then records the energy reflected or refracted back to the sensor.
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) – Optical sensor onboard Terra, which was launched in December 1999 as part of NASA's Earth Observing System (EOS). ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI) and Japan's Earth Remote Sensing Data Analysis Center (ERSDAC).
Afforestation – The process of planting trees and/or seeds in areas not previously forested.
Angular field of view – The area or solid angle, which can be viewed through an optical instrument. In photography, angle of view (also called Angle of Coverage or Field of View) is the amount of a given scene shown on the film or image sensor (in analogue and digital photography, respectively). Various lenses record different degrees of the total image.
Backscatter – Backscatter is the portion of the outgoing radar signal that the target redirects back to the radar antenna.
Band – A portion or wavelength interval of the electromagnetic spectrum -, sometimes called a channel.
Biodiversity – Refers to the variety of life on earth. The most widely accepted definition of biodiversity is found in Article 2 of the Convention on Biological Diversity: “Biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.”
Biodiversity Hotspot – Refers to an area containing exceptionally high species diversity, in particular areas including many unique or endemic species.
Biophysical – The biological and physical components of the environment (Australian EPA 2007).
Biosphere reserve – An international conservation designation given by UNESCO under its Programme on Man and the Biosphere (MAB). The World Network of Biosphere Reserves is the collection of all 507 biosphere reserves in 102 countries (as of December 2006).
Buffer zone – An area extending radially, by a defined distance, around a feature of interest.
CBFM (Community-Based Forest Management) – An approach to forest management that entitles forest communities to use and develop certain forest land and resources.
Convention on Biological Diversity (CBD) – An agreement signed by 150 world leaders at the 1992 Earth Summit in Rio de Janeiro. The goals of the CBD include the conservation of biodiversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from genetic resources.
Critically endangered – Facing an extremely high risk of extinction in the wild.
Deforestation – The conversion of forested area to non-forested area through the removal of trees.
Degradation – A reduction in the biological productivity of an area of land.
Digital Elevation Model (DEM) – Representation of elevation as a regular grid where each cell has an elevation value. These grids can be derived from other elevation information such as contours, topographic maps, irregularly spaced spot heights, or from satellite images.
Digital Number (DN) – A value assigned to each cell in a grid (image); the digital number may represent the brightness of an image.
Earth Observation (EO) – The study of Earth and its changing environment by observing the atmosphere, oceans, and land through remote sensing technologies.
Ecology – The scientific study of: 1) the interactions or relationships between organisms and their environment, 2) the interactions that determine the distribution and abundance of organisms.
Ecosystem – An interacting ecological unit comprising the biotic community and abiotic environment within a defined area.
Ecosystem diversity – Refers to the variety of identifiable ecosystems in which organisms live.
Ecosystems – Groups and communities of organisms (animals, plants, insects and micro-organisms) that form one functioning unit. It also includes all of the non-living physical and chemical factors of the environment that maintain its existence, linked together through nutrient cycling and energy flow.
Ecotone – An area of transition or overlap between two habitat types.
Endangered – Facing a very high risk of extinction in the wild.
Endemic – Occurring naturally in only one specific area.
Environmental monitoring – The collection of systematic observations of the environment to detect changes over time and space.
Erosion – The wearing away, detachment, and movement of surface materials by forces of wind, water, or ice.
False Colour – A colour imaging process that produces an image of a colour that does not correspond to the true colour of the scene (as seen by human eyes).
Fragmentation – The breaking up of a habitat into unconnected patches interspersed with other habitat, which may be considered degraded compared to the original habitat. The breaking may be by human or non-human action, for example, changing natural forest for plantation, or forest-fire, or building a new highway. Fragmentation may have negative impacts on species that require a minimum area of specific habitat to maintain viable populations.
Geographic Information System (GIS) – Computer-based system for capturing, storing, checking, integrating, analysing and displaying geographic data.
Geometric correction – The geographic correction of image data to conform to a map projection. Ground control points are often used to increase the accuracy of the correction process.
Geostationary (orbit) – An orbit around the Earth whereby a satellite travels in the same direction and completes the orbit in the same time as the Earth completes a revolution. Hence, the satellite maintains a fixed position relative to the surface of the Earth.
Global Positioning System (GPS) – A global navigation system that utilizes a network of satellites to provide accurate estimates of geographic location, speed and altitude. Positional information can be received and stored using a GPS handset. These handsets are used to store location information for sites where field data has been collected and/or observations made. GPS points are also useful for recording the time and position of photographs.
Ground resolution – The minimum distance on the ground between two closely located objects at which they are distinguishable as separate objects.
High Conservation Value Forest – Related to the function of a forest at a local, regional or global scale. These may be clear functions, such as watershed protection or the maintenance of a food resource for local people. But these functions also include more intrinsic elements such as a community of endemic species, which may have no clear economic value but are important for the maintenance of the diversity of life (Pollard, 2004).
Hyper-spectral – A satellite sensor with many narrow bands or channels – sometimes a 1,000 or more.
Image – In remote sensing and GIS, a term that describes digital data stored as discrete pixels that represent feature of the Earth’s surface.
Image Classification – A process that groups pixels with similar digital number values into classes or categories to produce a thematic representation. Digital image classification procedures are differentiated as being either supervised or unsupervised classification.
Image enhancement – Any operation intended to improve the visual appearance of an image. These operations include, but are not limited to, contrast improvement, edge enhancement, spatial filtering, noise suppression, image smoothing, and image sharpening.
Image pre-processing – Encompasses all the various operations which can be applied to photographic or image data. These include, but are not limited to, image compression, image registration, image enhancement, spatial filtering, and other image pattern recognition techniques.
Irrigated Agriculture – Agriculture that depends on supplemental water to provide sufficient water for successful production of a crop.
Joint protection – The joint management of natural resources with the aim of protecting the resource(s) in question; by multiple parties, including neighbouring states, provinces or different government departments of the same country.
Land cover – The observed physical cover of the land, such as vegetation or man-made features.
Land use – How people use the Earth’s surface, for example parkland, or agriculture. There can be many different uses of the same land cover.
Landsat Satellite (Landsat) – The first satellite in the “Landsat series” was launched in 1972. Subsequent satellites have improved sensor technology (e.g., Enhanced Thematic Mapper). The long times series of data has made Landsat the most successful civilian Earth observation program.
Landscape – A heterogeneous land area composed of a cluster of interacting ecosystems that is repeated in similar form throughout (MSU, 2007).
Moderate Resolution Imaging Spectroradiometer (MODIS) – MODIS is an instrument aboard the Terra (EOS AM) and Aqua (EOS PM) satellites. Terra MODIS and Aqua MODIS are viewing the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths. The maximum resolution of MODIS is 250m.
Monitoring and Evaluation – Monitoring can be defined as a continuing function that aims to provide the management and main stakeholders of an ongoing project with indications of progress, or lack of progress in the achievement of results. Evaluation is a selective exercise that attempts to systematically and objectively assess progress towards the achievement of an outcome. Evaluation is often carried out at several points in time during the effort to achieve an outcome. All evaluations need to be linked to outcomes, as opposed to only implementation or immediate outputs. (UNDP 2002)
Multi-spectral scanner (MSS) – Array of sensors that detect electromagnetic radiation simultaneously in several spectral bands. Scanning along the flight direction is achieved by movement of the platform. Scanning across the flight direction is achieved by oscillation (rotation) of a mirror. Device used on the Landsat satellites.
Nadir – A single point on the surface of the Earth directly below a sensor as it progresses along its line of flight.
Non-timber forest products – Items available from forests, other than wood products, such as rubber, nuts, and medicines.
Normalized Difference Vegetative Index (NDVI) – The Normalized Difference Vegetative Index (NDVI) is calculated from reflectance measured in the visible and near infrared bands. The index is related to the amount/vigour of green vegetation.
Orbit – In remote sensing, the path of a satellite around the Earth; altitude is an important parameter.
Panchromatic imagery – Image where all wavelengths within the visible spectrum were recorded (though not uniformly).
Passive Sensors – A sensing system that detects or measures radiation emitted or reflected by the target.
Photogrammetry – The application of photographic principles to the science of mapping. The science of obtaining reliable spatial measurements from imagery.
Photosynthesis – The process by which plants use energy from the sun to transform carbon dioxide (CO2) and water into carbohydrates and other compounds.
Pixel – “Picture element” is the ground area corresponding to a single element of a digital image. A two-dimensional array of pixels forms the grid that makes an image.
Poaching – A term used to describe illegal or prohibited hunting.
Polarization – In simple terms this is the orientation of the electromagnetic wave; can be linear (vertical or horizontal) or circular.
Principal Component Analysis (PCA) – Statistical technique that can be used to simplify an image dataset. It is a transformation so that the greatest variance in an image is represented as a principal component.
Protected area – Protected areas are the cornerstones of national and international conservation strategies. They act as refuges for species and ecological processes that cannot survive in intensely managed landscapes and seascapes. They provide space for natural evolution and future ecological restoration. People – nearby and further afield – benefit from the genetic potential of wild species, the environmental services of natural ecosystems, recreational opportunities and the refuge given to traditional and vulnerable societies (WWF 2003).
RADARSAT-1 – A radar satellite operates at a single microwave frequency, C‑band (5.3 GHz frequency or 5.6 cm wavelength), which generates one channel of image data. The “one-channel” image can be combined with multi-temporal composites to create color images. The imaging re-visit cycle is 24 days, and resolution ranges from 8 meters to 100 meters. RADARSAT data is especially useful for flood and wetland monitoring.
RADARSAT-2 – A new radar satellite scheduled to be launched in 2007. Additional capabilities include: 3-meter ultra-fine resolution; more frequent re-visit; multi- and cross-polarisation (HH, HV, VH, VV); faster response to user requests.
Radio Detection and Ranging (RADAR) – Traditional radar sends directional pulses of electromagnetic energy and detects the presence, position and motion of an object by analyzing the portion of the energy reflected from the object back to the radar station. Imaging radar attempts to form a picture of the object.
Radiometric correction – Calibration of image values, for example because of atmospheric interference.
Radiometric enhancement – Improving the interpretation of the information in an image, for example using a filter.
Radiometric resolution – Sensitivity of the sensor for recording values of electromagnetic energy.
Ramsar Convention – An international treaty for the conservation and sustainable utilization of wetlands, i.e. to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural, scientific, and recreational value. The treaty was signed in 1971 and came into force in 1975, (Ramsar 2007).
Red list – The IUCN Red List of Threatened Species (also known as the "IUCN Red List" and "Red Data List"), created in 1963, is the world's most comprehensive inventory of the global conservation status of plant and animal species and can be found here. It is maintained by the World Conservation Union.
Reforestation – The process of restoring and replacing tree cover from areas where deforestation of forested areas has previously occurred.
Remote Sensing – The science, technology and art of obtaining information about objects or phenomena from a distance (i.e., without being in physical contact with them).
Resolution – see Ground Resolution.
Revisit Period – Satellites travel in an orbit that mean the satellite sensor can regularly observe the same location on Earth’s surface. The time between these passes over the same location is the revisit period. It is important for an application that requires frequent monitoring, such as flood monitoring or fire detection.
Satellite Pour l'Observation de la Terre (SPOT) – A series of French satellites. SPOT images are based on visible and near-infrared wavelength instruments. The primary SPOT imaging instrument consists of two identical visible sensors that can record digital images in either a multi-spectral mode with a ground resolution of 10 m and 20 m, or panchromatic images at 2.5 m and 5 m.
Shuttle Radar Topography Mission (SRTM) – A joint project between the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA), the USA. The project produced freely available digital elevation data for most of the Earth's land surface, with data points located every 3-arcsecond on a latitude/longitude grid (approximately 90 m at the equator). The absolute vertical accuracy of the elevation data is 16 meters (90% confidence).
Spatial filter – An image enhancement method that modifies pixel values based on the values of the surrounding pixels ('neighbourhood'), with the objective of enhancing information of high or low spatial frequency. Areas that have a low spatial frequency experience little change over a distance, for example a flooded area may have uniform dark tone. Areas that have a high spatial frequency have abrupt changes in brightness over very small distances, for example a forested area. Spatial filters can also be designed to highlight boundaries between different surface features.
Species diversity (organism diversity) – Refers to the variety of species that exists (or is thought to exist) within a region. Species diversity can refer to either the actual number of species (known as species richness) or to other indices of diversity that account for the relationships between species (e.g., relative abundance).
Spectral resolution – The ability of a sensing system to resolve or differentiate electromagnetic radiation of different wavelengths.
Spectral Signature – Quantitative measurement of the properties of an object or area in several wavelengths, which can be used as a means to identify an object or area.
Stakeholder – Any individual or group affected by and with an interest in a specific resource, project, program, or policy.
Sun-synchronous – Most satellites are synchronized with the sun so they make repeat passes over a particular area at the same time of day. This ensures that sun angle and shadowing will be similar in images acquired over the same area on different orbits. Most orbits are timed with mid-morning equatorial crossings so that image acquisitions occur when the sun angle is low.
Supervised Classification – An image classification procedure requiring the input of information by an image analyst. Usually, this involves defining the statistical properties of required classes through “training sites”, which are areas of known land cover. The training site statistics are then used as a basis for allocating the remaining areas of an image to one of the desired classes.
Sustainability – Refers to the ability to maintain a defined state over time. In terms of resource use and development, sustainability refers to the ability to meet the needs of the present without compromising the ability to meet the needs of the future.
Sustainable development –Defined by the Brundtland Report as “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” (WCED 1987).
Swath – The width of the ground area covered by a sensing system along the path of the sensor.
Texture – The frequency of change and arrangement of tones in an image, or the pattern of spatial tone variation. It may be described as fine, medium, or coarse, and texture may be related to specific land cover, such as forest or grassland.
Topography –The shape and configuration of the land surface as described by the position of physical features, elevation, slope, and orientation.
Traditional Ecological Knowledge (TEK) – Traditional knowledge is a cumulative body of knowledge, know-how, practices and representations maintained and developed by peoples with extended histories of interaction with the natural environment. These sophisticated sets of understandings, interpretations and meanings are part and parcel of a cultural complex that encompasses language, naming and classification systems, resource use practices, ritual, spirituality and worldview. Traditional and local knowledge systems as dynamic expressions of perceiving and understanding the world, can make and historically have made, a valuable contribution to science and technology, and that there is a need to preserve, protect, research and promote this cultural heritage and empirical knowledge.
True Colour (Normal Colour) – A colour imaging process whereby the colour of the image is the same, or similar, to the colour of the object perceived by the human eye.
Unsupervised Classification – Classification of digital image data by computer processing based on the image statistics without the use of other information or knowledge of the area under study. The classification creates spectral clusters or classes, which have similar spectral characteristics (often in several bands). Spectral clusters may or may not be related to unique land cover types, and an image analyst must determine how spectral clusters are interpreted.
Visible Near-Infrared (VNIR) – The electromagnetic spectrum is divided on the basis of wavelength into regions, which range from very short wavelengths (i.e., gamma ray) to long wavelengths (i.e., radio region). The visible region occupies only a small portion of the spectrum. Remote sensing records energy in the microwave, infrared, and visible regions. The major remote sensing regions are further sub-divided into bands, e.g., the blue, green, and red bands of the visible region.
Wetland – An area that is seasonally or permanently saturated with water, and is transitional between terrestrial and aquatic ecosystems. The Convention on Wetlands (Ramsar, Iran, 1971) defines wetlands as “Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed 6 m.
World Heritage Site – A globally significant site: an area or structure designated by UNESCO as being of global significance and conserved by a country that has signed a United Nations convention pledging its protection. (UNESCO 2007)
Zenith point – Directly overhead.
Australian EPA (2007). Department of Environment and Conservation, NSW, Australia
WCED (1987). Our Common Future. UN World Commission on Environment and Development (WCED), Oxford University Press. Also available from http://www.anped.org/media.php?id=475
MSU (2007). Glossary of Conservation Terms. Michigan State University http://www.msu.edu/~jaroszjo/greenway/glossary/glossary.htm
Pollard E.H.B. (Ed.) 2004. Toolkit for the Identification of High Conservation Value
Forest in Viet Nam - Draft 1. A synthesis of consultation with experts, Hanoi
15th to 18th November, 2004.
Ramsar (2007). Recommendations adopted by the International Conference on the Conservation of Wetlands and Waterfowl at Ramsar, Iran, 3 February 1971. http://www.ramsar.org/key_final_act_1971.htm#recs
UNDP (2002). Handbook on Monitoring and Evaluating for Results. United Nations Development Programme Evaluation Office. New York, USA.
UNESCO (2007) World Heritage Convention website http://whc.unesco.org/en/conventiontext/
WWF (2003) Position Paper on Protected Areas. WWF International, Gland Switzerland.
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