Definitions Flashcards
Accuracy
The closeness of observations, computations, or estimates to the true values or to values accepted as being true
Aerial
Of, pertaining to, or occurring in the air or atmosphere
Aerial Photograph, Oblique
An aerial photograph taken with a camera axis directed between the horizontal and the vertical.
(1) high oblique - an oblique photograph in which the horizon is shown
(2) low oblique - an oblique photograph in which the horizon is not shown
Aerial Photograph, Vertical
An aerial photograph made with the optical axis of the camera approximately perpendicular to the earth’s surface and with the film as nearly horizontal as is practical
Algorithm
A statement of the steps to be followed in the solution of a problem; an algorithm may be in the form of a word description, an explanatory note, or a labeled diagram or flowchart
Alluvium
Any material deposited by running water; the soil material of floodplains and alluvial fans
Altitude
Elevation above or below a reference datum; the datum is usually the mean sea level
Analog
A form of data display in which values are shown in graphic form, such as curves
Aquifer
Any subsurface material that holds a relatively large quantity of groundwater and is able to transmit that water readily
Area
A generic term for a bounded, continuous, two-dimensional object that may or may not include its boundary
Aspect
The horizontal direction in which a slope faces, commonly expressed as compass direction (for example, North, Northeast); degrees clockwise from the North
Attribute
A defined characteristic of an entity (for example, topographic slope)
Attribute Value
A specific quality or quantity assigned to an attribute (for example, 15 percent slope)
Band
A specific frequency or range of frequencies in the electromagnetic spectrum
Baseflow
The portion of streamflow contributed by groundwater; it is a steady flow that is slow to change even during rainless periods
Berm
A low, linear mound of earth and soil
Buffer
(1) The zone around the perimeter of a wetland or lake where land-use activities are limited to protect the water features;
(2) a zone of a specified distance around any map feature in a GIS layer
Cadastre
a parcel-based land information system
Carrying Capacity
The level of development density or use that an environment is able to support without suffering undesirable or irreversible degradation
Characterization
The delineation or representation of the essential features or qualities existing at a site
Chloropleth Map
a map comprised of areas of any size or shape representing qualitative phenomena (for example, soil fertility) or quantitative phenomena (for example, elevation); often has a mosaic appearance
Climate
The general or representative conditions of the atmosphere at a place on earth
Clustering
A land development concept in which buildings and infrastructures are grouped together, and large contiguous areas of open space remain undeveloped
Coefficient of Runoff
A number given to a type of ground surface representing the proportion of rainfall converted to overland or surface flow
Color-Infrared Film
Photographic film sensitive to energy in the visible and near-infrared wavelengths of the electromagnetic spectrum (usually from 0.4 to 0.9 mm)
Concentration Time
The time taken for a drop of rain falling on the perimeter of a drainage basin to pass through the basin to the outlet
Constraint
Any feature or condition of the built or natural environment that poses an obstacle to proposed land uses
Contour
An imaginary line on the ground, all points of which are at the same elevation above or below a specific datum
Contour Interval
The difference in elevation between two adjacent contours
Control Point
Any station in a horizontal or vertical control system that is identified on a photograph and used for correlating the data shown on the photograph
Coordinate System
A reference system for uniquely defining the location of any point on earth
Crown Diameter, Visible
The apparent diameter of a tree crown imaged on a vertical aerial photograph
Data Set
A file or files that contain related geometric and attribute information; a collection of related data
Datum
A reference system for measuring another attribute, such as horizontal or vertical location
Decibel
A unit of measurement for the loudness of sound based on the pressure produced in air by a noise; denoted as dB
DEM (Digital Elevation Model)
A topographic surface arranged in a data file as a set of regularly spaced x, y, z coordinates, in which z represents elevation
Design Storm
A rainstorm of a given intensity and frequency of recurrence that is used as the basis for stormwater management
Detention
A strategy used in stormwater management in which runoff is detained on-site to be released later at some prescribed rate
Development Density
A measure of intensity of development or land use; defined, for example, on the basis of area covered by dwelling units, impervious surfaces, or building floor area
Digitization
The process of converting a photograph, map, or other image into numerical format
Discharge
The rate of water flow in a stream channel or from a site; measured as the volume of water passing through a cross-section of a stream or swale per unit of time, commonly expressed as cubic feet (or meters) per second
Discharge Zone
An area where groundwater seepage and springs are concentrated
Disturbance
An impact on the environment, such as forest clearing, characterized by physical or biological change
DLG (Digital Line Graph)
A digital representation of cartographic information; digital vectors converted from maps and related sources
DOQ (Digital Orthophotoquadrangle)
A digital image with the properties of an orthographic projection; derived from a digitized vertical aerial photograph so that image displacement caused by camera tilt and relief of terrain are removed, or rectified. Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map
Drainage Network
A system of stream channels usually connected in a hierarchical fashion
Drainage Basin
The area that contributes runoff to a stream, river, of lake
Easement
A right-of-way granted, but not dedicated, for limited use of private land for a public or quasi-public purpose
Ecosystem
A group of organisms linked together by a flow of energy; it is also a community of organisms and their environment
Ecotone
The transition zone between two groups, or zones, of vegetation
Electromagnetic Radiation (EMR)
Energy propagated through space in the form of an advancing interaction between electric and magnetic fields. EMR is also called electromagnetic energy.
Elevation
Vertical distance from a datum point, such as mean sea level, to a point or object on the earth’s surface; not to be confused with altitude, which refers to points or objects above the earth’s surface
Endangered Species
According to the U.S. Endangered Species Act, a species of imminent danger of extinction in all or a significant portion of its range
Environment
The aggregate conditions that affect the existence or development of properties intrinsic to a site
Environmental Site Characterization
The delineation or representation of the essential features or qualities, including all of the conditions, influences, and circumstance, existing at a place or location designated for a specific use, function, or study
Environmental Assessment
A preliminary study or review of a proposed action (project) and the influence it could have on the environment; often conducted to determine the need for more detailed environmental impact analysis
Ephemeral Stream
A stream without base flow; one that flows only during or after rainstorms or snowmelt events
Erosion
The removal of rock debris by moving water, wind, or another agent; generally, the sculpting or wearing down of the land by erosional agents
Eutrophication
The increase of biomass of a water body leading to infilling of the basin and the eventual disappearance of open water
Evapotranspiration
The loss of water from the soil through evaporation and transpiration
Feasibility Study
A type of planning aimed at identifying the most appropriate use of a site
Filtration
A term generally applied to the removal of pollutants, such as sediment, with the passage of water through a soil, organic, and/or fabric medium
Floodway Fringe
The zone designated by U.S. federal flood policy as the area in a river valley that would be lightly inundated by the hundred-year flood
Floor Area
The area of all floors of a building or structure
Footprint
Area covered by a building
Geocoding
A coding process in which a digital map feature is assigned an attribute value (for example, vertical or horizontal location)
Geographic Information System (GIS)
A mapping system designed for analysis, planning, and management applications involving overlapping and complex distributional patterns. Two classes of GIS are vector and raster.
Geomorphology
A science that deals with the land and submarine relief features of the earth’s surface, or the comparable features of a celestial body, and seeks a genetic interpretation of them.
Georeference
To establish the relationship between coordinates on a planar map and real-world coordinates
Geospatial Data
Information identifying the geographic location and characteristics of natural or constructed features and boundaries on the earth; geospatial data may be derived from, among other things, remote sensing, mapping, and surveying technologies
Geostationary Satellite
A satellite placed in orbit above the earth; it rotates with the earth and, thus, remains fixed over the same area.
Global Positioning System (GPS)
The Navigation Satellite Timing and Ranging (NAVSTAR) GPS is a passive, satellite-based, navigation system operated and maintained by the Department of Defense (DOD)
Global Coordinate System
The network of east-west and north-south lines (parallels and meridians) used to measure locations on earth; this system uses degrees, minutes, and seconds as the units of measurement
Gradient
The inclination or slope of the land, often applied to systems such as streams and highways
Ground Truth (jargon)
The term coined for data and information obtained on surface or subsurface features to aid in interpretation of remotely sensed data; ground data and ground information are the preferred terms.
Ground Resolution
The area on the terrain that is covered by the instantaneous field of view of a detector; ground resolution is determined by the altitude of the remote-sensing system and the instantaneous field of view of the detector
Ground Data
Data collected on the ground, and information derived there from, as an aid to the interpretation of remotely recorded surveys, such as airborne imagery; generally, this should be performed concurrently with the airborne surveys; data collected on weather, soils, and vegetation types and conditions are typical
Groundwater
The mass of water that occupies the subsoil and upper bedrock zone; the water occupying the zone of saturation below the soil-water zone
Habitat
The local environment from which an organism gains its resources; habitat is often variable in size, content, and location, changing with the phases in an organism’s life cycle
Hardpan
A hardened soil layer characterized by the accumulation of colloids and ions
Hazard Assessment
An evaluation of the dangers to land use and people from environmental threats such as floods, tornadoes, and earthquakes
Horizon
A layer in the soil that originates from the differentiation of particles and chemicals due to moisture movement within the soil column
Hydric Soil
Soil characterized by wet conditions, or saturation, most of the year - often organic in composition
Hydrograph
A streamflow graph that shows the change in discharge over time, usually hours or days
Hydrologic Cycle
The planet’s water system, described by the movement of water from the oceans to the atmosphere to the continents and back to the sea
Impervious Cover
Any hard surface material, such as asphalt or concrete, that limits stormwater infiltration and induces high runoff rate
Infiltration Capacity
The rate at which a ground material takes in water through the surface; measured in inches or centimeters per minute or hour
Infrared Image
An image acquired within the wavelength from about 0.7 mm to about 2.6 mm; thermal infrared is between 2.6 mm and 13.5 mm
Infrared Film
Photographic film capable of recording near-infrared radiation (just beyond the visible to a wavelength of 0.9 micrometer), but not capable of recording thermal infrared wavelengths
Infrared Radiation
Mainly long wave radiation of wavelengths between 3.0-4.0 and 100 micrometers; it includes near-infrared radiation, which occurs at wavelengths between 0.7 and 3.0-4.0 micrometers
Isopleth Map
A map comprised of lines (isolines) that connect points of equal attribute value
Lacustrine Wetland
A wetland associated with standing water bodies such as ponds, lakes, and reservoirs
Land Cover
The materials such as vegetation and concrete that cover the ground. See also Land Use.
Land Use
The human activities occurring within an area of the landscape; for example, agricultural, industrial, and residential uses
Layer
In a geographic information system, spatial data of a common type or theme
Legend
An explanation of the symbols, colors, and styles used on a map or plan, usually in a box next to the map or plan
Lithosphere
The solid part of the earth or other spatial body, distinguished from the atmosphere and the hydrosphere
Lot
A parcel, tract, or area of land established by a plat or otherwise as permitted by law
Lot Frontage
The portion of a lot adjacent to a street
Magnetic Declination
The deviation in degrees east or west between magnetic north and true north
Map
A graphical representation of a portion of the earth’s surface, drawn to scale, on a specific projection, showing natural and manmade features
Map Projection
An orderly system of lines on a plane representing a corresponding system of imaginary lines on a datum surface
Metadata
“Data about data” describe the content, quality, condition, and other characteristics of data; for example, the date and source from which field data were collected
Monochromatic
Pertaining to a single wavelength or, more commonly, to a narrow band of wavelengths
Microclimate
The climate of small spaces, such as inner city, a residential area, or a mountain valley
Mitigation
A measure used to lessen the impact of an action on the natural or human environment
Mitigation Banking
In wetland mitigation planning, the practice of building surplus acreage of compensation credits through replacement, enhancement, restoration, and/or preservation of wetlands
Moraine
The material deposited directly by a glacier; the material (load) is also carried in or on a glacier; as landforms, moraines usually have either hilly or rolling topography
Mosaic
A term used in landscape ecology to describe the patchy character of habitat as a result of fragmentation through land use; an assemblage of overlapping aerial or space photographs or images whose edges have been matched to form a continuous pictorial representation of a portion of the earth’s surface
Nonpoint Source
Water pollution from a spatially diffuse source such as the atmosphere or agricultural land
Palustrine Wetland
Wetlands associated with inland sites that are not dependent on streams, lakes, or oceanic water
Panchromatic
A term used for films that are sensitive to broadband (that is, the entire visible part of the electromagnetic spectrum)
Parent Material
The particulate material in which a soil forms; the two types of parent material are residual and transported
Peak Discharge
The maximum flow of a stream or a river in response to an event such as a rainstorm, or over a period of time such as a year
Percolation Rate
The rate at which water moves into soil through the walls of a test pit; used to determine soil suitability for wastewater disposal and treatment
Percolation Test
A soil-permeability test performed in the field to determine the suitability of a material for wastewater disposal and treatment
Permeability
The rate at which soil or rock transmits groundwater (or gravity water in the area above the water table)
Photogrammetry
The art or science of obtaining reliable measurements by means of photography
Photosynthesis
The process by which green plants synthesize water and carbon dioxide and, with the energy from absorbed light, convert it into plant materials in the form of sugar and carbohydrates
Physiography
A term from physical geography that is traditionally used to describe the composite character of the landscape over large regions
Planned Unit Development (PUD)
An area planned, developed, operated, and maintained as a single entity containing one or more structures and common areas; it may include multiple land uses (for example, commercial or residential)
Plat
A map or maps of a subdivision or site plan
Point Source
Water pollution that emanates from a single source such as a sewage plant or stormwater outfall
Radiation
The process by which radiant (electromagnetic) energy is transmitted through free space; the term used to describe electromagnetic energy, as in infrared radiation or short-wave radiation
Rainfall Intensity
The rate of rainfall measured in inches or centimeters of water deposited on the surface per hour or minute
Rational Method
A method of computing the discharge from a small drainage basin in response to a given rainstorm; computation is based on the coefficient runoff, rainfall intensity, and basin area
Recharge Zone
An area where groundwater recharge is conentrated
Recharge
The replenishment of groundwater with water from the surface
Relief
The range of topographic elevation within a prescribed area
Retention
A strategy used for stormwater management in which runoff is retained on-site in basins, underground, or released into the soil
Right-of-Way
A strip of land occupied or intended to be occupied by a street, one or more walkways, utility lines, or other special uses
Riparian Wetland
Wetlands that form on the edge of a water feature such as a lake or stream
Riparian
The environment along the banks of a stream, often more broadly applied to the larger lowland corridor on the stream valley floor
Risk Management
An area of planning that involves preparation and response to hazards such as floods, hurricanes, and toxic waste accidents
Rubber Sheet
A procedure to adjust features of a digital GIS layer in a nonuniform manner; representing “from” and “to” locations are used to define the adjustment
Runoff
The flow of water from the land as both surface and subsurface discharge; in the more restricted and common use, surface discharge is in the form of overland flow and channel flow
Scale
The relationship between a distance on a map, chart, or photograph and the corresponding distance on the earth
Septic System
A sewage system that relies on a septic tank to store and/or treat wastewater; generally, an on-site (small-scale) sewage disposal system that depends on the soil for wastewater treatment
Setback
The minimum distance that a structure or facility should be separated from an edge, such as a property line.
Siltation
The deposition of sediment in water due to soil erosion and stormwater runoff.
Soil Profile
The sequence of horizons, or layers, of a soil.
Solar Heating
The process of generating heat from absorbed solar radiation.
Solar Gain
The amount of solar radiation absorbed by a surface or setting in the landscape.
Solstice
The dates when the declination of the sun is at 23.27 degree north latitude (the Tropic of Cancer) and 23.27 degrees south latitude (Tropic of Capricorn) - June 21-22 and December 21-22, respectively.
Spatial Data
Data or information with implicit or explicit information about location.
Stream Order
The relative position, or rank, of a stream in a drainage network. Streams without tributaries, usually the small ones, are first order; streams with two or more first-order tributaries are second order, and so on.
Subdivision
The division of a lot, tract, or parcel of land into two or more lots, tracts, or parcels for sale or development.
Sun Angle
The angle formed between the beam of incoming solar radiation and a plane at the earth’s surface.
Surge
A large and often destructive wave caused by intensive atmospheric pressure and strong winds.
Threatened Species
According to the U.S. Endangered Species Act, a species with a rapidly declining population that is likely to become endangered.
TIN
Triangulated irregular network. A surface representation derived from irregularly spaced points and breakline features. Each sample point has an x, y coordinate and a z (surface) value.
Topsoil
The uppermost layer of the soil, characterized by a high organic content.
Water Table
The upper boundary of the zone of groundwater. In fine-textured materials it is usually a transition zone rather than a boundary line. The configuration of the water table often approximates that of the overlying terrain.
Wellhead Protection
Land-use planning and management to control contaminant sources in the area contributing recharge water to community wells.
Wetland
An area where the ground is permanently wet or wet most of the year and is occupied by water-loving (or tolerant) vegetation, such as cattails, mangrove, or cypress.
Zenith
For any location on earth, the point that is directly overhead to an observer.
Adaptation
A genetically determined characteristic that enhances the ability of an organism to better adjust to its surroundings.
Adiabatic Lapse Rate
A variation in temperature of a parcel of air up or down a change in elevation. This does not take into account exchanges of heat between the air parcel and the environment.
Administration
Execution of an organizational policy to reach predetermined objectives.
Advection
The transfer of an atmospheric property due to mass air motion along a gradient of the property in question; the horizontal spreading of local effects by wind.
Agricultural District
A legally recognized geographic area formed by one or more landowners and approved by one or more government agencies, designed to keep land in agriculture. Agricultural districts are created for fixed, renewable terms. Enrollment is voluntary; landowners receive a variety of benefits that may include eligibility for differential assessment, limits on annexation and eminent domain, protection against unreasonable government regulation and private nuisance lawsuits, and eligibility for purchase of agricultural conservation easement programs. Agricultural districts are also known as agricultural preserves, agricultural security areas, agricultural preservation districts, agricultural areas, agricultural incentive areas, agricultural development areas, and agricultural protection areas
Agricultural lands
Places used for crop or animal production or for silviculture.
Agricultural Zoning
A zoning ordinance or zoning district design to protect farmland from incompatible nonfarm uses. There are several types of agricultural zoning, which vary according to (1) the uses allowed in the zone (i.e., exclusive or nonexclusive farm use); (2) the minimum farm size allowed, such as a 50-acre (20.2-hectare) minimum lot size; (3) the number of nonfarm dwellings allowed, such as one building lot per 25 acres (10.1 hectares); and (4) the size of setbacks or buffer areas between farms and nonfarm properties
Air Mass
A widespread body of air that gains certain characteristics while set in one location. The characteristics change as it moves away.
Air Parcel
A space of air over a certain area of land.
Air Pollution Areas
Places that require restraints on air pollution emissions due to periods of poor vertical air mixing and the subsequent entrapment of polluting substances.
Albedo
Reflected solar radiation factor.
Alluvium
The soil material deposited by running wtaer.
Analysis
The examination of individual parts to find out their nature, function, and interrelationship with other parts.
Abiotic
Those aspects dealing with nonliving matter
Annexation
The incorporation of land into an existing community that results in a change in the community’s boundary. Annexation generally refers to the inclusion of newly incorporated land but can also involve the transfer of land from one municipality to another.
Aquifer
A water-bearing layer of permeable rock, sand, or gravel
Aspect
Orientation toward some direction
Basalt
A hard, fine-grained igneous rock caused by volcanism
Base Map
A reproducible map used to display various types of information.
Biodiversity (biological diversity)
The variety and abundance of all life-forms considered at all levels of organization, from the genetic level through the species and higher levels of taxonomic organization, and including the variety of habitats, communities, landscapes, and ecosystems.
Biogeochemical cycles
Mineral and nutrient cycles that are important to the biological community
Biological
Those aspects dealing with living matter
Biosphere
The portion of earth and its atmosphere that can support life
Biota
All living organisms that exist in an area
Biotic Community
An assemblage of plants and animals living in the same community, forming a system that is mutually sustaining and interdependent and influenced by the abiotic factors of the ecosystem. A biotic community is generally characterized by the dominant vegetation.
Board of Adjustment
An independent board created to handle conditional uses, variances, and special applications of regulations established by a zoning ordinance and to hear and act on appeals.
Building Code
The legal requirements pertaining to the building of structures.
Canopy Layer
The uppermost layer of forest vegetation.
Capability
An evaluation based on a resource’s inherent, natural, or intrinsic ability to provide for use and includes that existing ability that is the result of past alterations or current management practices. Often capability is used interchangeably with suitability.
Capability Class
An evaluation made by the U.S. Natural Resources Conservation Service concerning the agricultural management of a soil type.
Capital Improvement Programming (CIP)
The multiyear scheduling of public physical improvements. The scheduling is based on studies of fiscal resources available and the choice of specific improvements to be constructed for a period of five or six years in the future.
Carnivores
Organisms that feed on animal issue.
Carrying Capacity
(1) In ecology, the number of individuals that the resources of a habitat can support.
(2) In wildlife, the maximum number of animals an area can support during a given period of the year.
(3) In recreation, the amount of use a recreation area can sustain without deterioration of its quality.
Circuit Breaker Tax Relief
A tax abatement program that permits eligible landowners to take some or all of the property tax they pay on farmland and farm buildings as a credit to offset their state income tax. Generally, farmers are eligible for a credit when property taxes exceed a set percentage of their income.
Citizen Participation
The involvement of the public in the planning process
Citizens’ Advisory Committee (CAC)
A group of citizens called together by an agency to represent the ideas and attitudes of their community in advising and giving consultation to the agency.
Clay
Soil particles smaller than 0.0002 millimeters in diameter.
Climate
The set of meteorological conditions characteristic of an area over a given length of time.
Cluster Development
Grouping houses on part of a property while maintaining a large amount of open space on the remaining land. Cluster development should be seen as an open-space protection tool rather than a farmland protection tool.
Cognitive Mapping
A process by which people acquire, code, store, recall, and decode information about the relative locations and attributes of phenomena in the everyday spatial environment.
Cohort-Survival Method
A popular method for making population projections based on fertility, mortality, and net migration.
Community
(1) In sociology, a variety of physical and social areas and institutions within which and with which people live.
(2) In ecology, an association of interacting populations, usually determined by their interactions by spatial occurrence.
Compensating Wind
Wind originating above plains and flowing toward nearby mountains along a pressure gradient.
Competition
The use or defense of a resource by one individual that reduces the availability of that resource to other individuals.
