<descriptor thcode="2"><thesaurus thcode="2" name="USGS Thesaurus" scope="Topics and methods of scientific study carried out by USGS, with product types, scientific disciplines, geologic time, and types of institutional structure and activities.  Broad and shallow, used to help people find scientific information." creator="U.S. Geological Survey" rights="Public domain" edition="2.0" date="2020-01-09" codetype="number" prefix="topic" uri="https://www2.usgs.gov/science/USGSThesaurus" tblname="term" nonpref="nonpref" relterm="relterm" root_code="1" contact="pschweitzer"><category><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/></category><altlabel><altlabel>USGSThesaurus</altlabel><altlabel>USGSThesaurus</altlabel></altlabel></thesaurus><term thcode="2" code="447" name="geography" parent="291" scope="Study of the earth's landforms, topography, and climate, the distribution of flora and fauna, and the distribution, culture, and activities of human populations."/><uf><usefor name="geographic information sciences"/></uf><bt><term thcode="2" code="291" name="earth sciences" parent="1019" scope="Broad term for all science related to the study of the earth."/><term thcode="2" code="1019" name="sciences" parent="1" scope="Major educational fields, fields of study, and professional groupings within USGS."/><term thcode="2" code="1" name="Categories" scope="Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."/></bt><nt><term thcode="2" code="147" name="cartography" parent="447" scope="The science and art of making maps."/><term thcode="2" code="1679" name="paleogeography" parent="447" scope="Study of the history of earth surface characteristics; geomorphology in the past."/></nt><rt><term thcode="2" code="74" name="AVHRR" parent="588" scope="Advanced Very High Resolution Radiometer or broad-band, four or five channel scanner, sensing in the visible, near-infrared, and thermal infrared portions of the electromagnetic spectrum. This information is used to estimate characteristics of the land and sea surface such as temperature and overall health of vegetation."/><term thcode="2" code="492" name="GPS measurement" parent="450" scope="Determination of distance and location using instruments receiving signals from the Global Positioning System, a system of satellites for identifying earth locations."/><term thcode="2" code="571" name="IFSAR" parent="981" scope="Interferometric comparison of radar reflectance imagery of the same area at different times to determine changes in the land surface, typically from a space-borne sensor."/><term thcode="2" code="1064" name="SLAR" parent="948" scope="Side-looking Airborne Radar, an airborne radar imaging technique, uses an antenna mounted on an airplane or satellite to project radiation at right angles to the flight path and collect high resolution images."/><term thcode="2" code="1069" name="SMMR" parent="742" scope="Scanning Multichannel Microwave Radiometer (SMMR), a technique which uses a multichannel microwave radiometer mounted on an airplane or satellite to measure polarized microwave radiances from the atmosphere, seas or land. Temperatures, wind speeds, sea ice coverage, and terrain parameters can be obtained."/><term thcode="2" code="1097" name="SSM/I" parent="742" scope="Special Sensor Microwave/Imager (SSM/I), technique using passive microwave radiometers aboard satellites to measure the microwave reflectivity of the earth, oceans, and the atmosphere."/><term thcode="2" code="12" name="administrative and political boundaries" parent="223" scope="Lines drawn on maps or described in documents which encompass territory controlled by a government or organizational unit that may or may not align with geographic or cultural barriers. Use for datasets containing boundary representations for political/administrative units and related information."/><term thcode="2" code="18" name="aeromagnetic surveying" parent="981" scope="Mapping of the earth's magnetic field with the use of airborne electronic magnetometers."/><term thcode="2" code="19" name="aeroradiometric surveying" parent="981" scope="Mapping of gamma radiation from the earth's surface with airborne scintillation meters or gamma-ray spectrometers."/><term thcode="2" code="36" name="altimetry measurement" parent="450" scope="The measurement of altitude, or height above mean sea level, using instruments such as aneroid barometers and radar altimeters."/><term thcode="2" code="82" name="bathymetry measurement" parent="450" scope="Means of determining the depth to the floor of a body of water, especially the ocean."/><term thcode="2" code="136" name="cadastral and legal land descriptions" parent="223" scope="Records in official registers showing extent, boundaries, and ownerships of land for administration and taxation."/><term thcode="2" code="223" name="culture and demographics" parent="1174" scope="Information on human behavior, ways of living and thinking, and characteristics of human populations."/><term thcode="2" code="440" name="geodesy" parent="470" scope="Branch of science dealing with measuring the earth or large areas of the earth for making maps, determining the size and shape of the earth, and correlating gravitational, geological, and magnetic surveys of the earth."/><term thcode="2" code="445" name="geographic information systems" parent="587" scope="Computer software that allows geospatially referenced data to be linked to geographic features. Use this term only for information that is about GIS and not for the use of GIS in applications and projects."/><term thcode="2" code="450" name="geolocation measurement" parent="376" scope="Methods for establishing a geographic location on the surface of the earth."/><term thcode="2" code="563" name="hyperspectral imaging" parent="981" scope="Multispectral imaging technique that records many bands of imagery at very narrow bandwidths."/><term thcode="2" code="574" name="image analysis" parent="189" scope="Pattern analysis of the shapes and textures of images to identify features and derive information about them."/><term thcode="2" code="588" name="infrared imaging" parent="981" scope="Method of remote sensing in which optical sensors produce visible representations of infrared rays or radiated heat from the observed objects and the temperature variations are represented by different colors in the image."/><term thcode="2" code="626" name="land surface characteristics" parent="287" scope="Features and attributes of earth's land surface."/><term thcode="2" code="627" name="land surveying" parent="450" scope="Determining property boundaries, land area, elevations, and locations of features on the surface of the land by calculations based on the instrumental measurements of angles and distances or by use of global positional satellites."/><term thcode="2" code="629" name="land use change" parent="548" scope="Effect of changing land use patterns on ecological systems."/><term thcode="2" code="648" name="lidar" parent="981" scope="Light detection and ranging, an airborne, spaceborne or ground-based laser-ranging technique commonly used for acquiring high-resolution topographic data."/><term thcode="2" code="692" name="map coordinate systems" parent="1174" scope="Systems using sets of numbers combined with geometric nets or grids to specific positions on a map or globe."/><term thcode="2" code="742" name="microwave imaging" parent="981" scope="Remote sensing method using short high frequency electromagnetic waves reflected or radiated from the ground."/><term thcode="2" code="765" name="multispectral imaging" parent="981" scope="A method of remote sensing that obtains optical representations in two or more ranges of frequencies or wave lengths."/><term thcode="2" code="867" name="panchromatic imaging" parent="981" scope="Photographic technique which uses emulsions, films, or plates sensitive to all colors in light to produce black-and-white photographs. Often used in aerial and satellite photography."/><term thcode="2" code="948" name="radar imaging" parent="981" scope="A remote sensing technique which uses the reflection of pulsed high frequency radio waves to determine the speed, direction, and distance of faraway objects."/><term thcode="2" code="981" name="remote sensing" parent="734" scope="Acquiring information about a natural feature or phenomenon, such as the Earth's surface, without actually being in contact with it. USGS remote sensing is usually carried out with airborne or spaceborne sensors or cameras."/><term thcode="2" code="1085" name="spatial analysis" parent="189" scope="Use of quantitative tools to study social, economic, and geographic data in relation to distributions and patterns in geographic space."/><term thcode="2" code="1161" name="thermal imaging" parent="981" scope="Remote sensing techniques using instruments to measure emitted thermal radiation to form images of the earth's surface."/><term thcode="2" code="1176" name="topography" parent="287" scope="Configuration of the land surface and sea floor."/><term thcode="2" code="1177" name="topological analysis" parent="189" scope="Branch of geometry concerned with the properties of objects that do not change even when deformed, twisted, stretched or otherwise changed in shape."/><term thcode="2" code="1281" name="visible light imaging" parent="981" scope="Remote sensing methods using electromagnetic radiation which is visible to the human eye to react with the coating on a photographic plate or film."/></rt></descriptor>