GIS Dictionary
background
[output] In ArcScene or ArcGlobe, the backdrop of the view. The color of the background can be set to suggest sky, empty space, or any color that improves visualization.
backscatter
[remote sensing] Electromagnetic energy that is reflected back toward its source by terrain or particles in the atmosphere.
BAM
[cartography] Acronym for best available map. The most suitable data source for a map.
band ratio
[digital image processing] A digital image-processing technique that enhances contrast between features by dividing a measure of reflectance for the pixels in one image band by the measure of reflectance … Read more
band separate
[remote sensing] An image format that stores each band of data in a separate file.
band-pass filter
[remote sensing] A wave filter that allows signals in a certain frequency to pass through, while blocking or attenuating signals at other frequencies.
bandwidth
[computing] The amount of digital data that can be transferred over a computer network within a specified time period, usually measured in bits per second (bps).
base data
[data analysis] Map data over which other, thematic information is placed.
base height
In aerial photography, the height or altitude from which a photograph is taken.
base height ratio
1 [aerial photography] In aerial photography, the distance on the ground between the centers of overlapping photos, divided by aircraft altitude. In a stereomodel, base height ratio is used to … Read more
base layer
[data analysis] A data layer in a GIS to which all other layers are geometrically referenced.
base station
[GPS] A GPS receiver at a known location that broadcasts and collects correction information for roving GPS receivers.
base symbol
[ESRI software] In ArcGIS Tracking Analyst, the default symbol used to represent an event or a feature on a map.
batch file
[computing] A text file containing commands that is sent to the CPU to be executed automatically. A batch file allows the central processing unit (CPU) to process the commands at … Read more
batch geocoding
[geocoding] The process of geocoding many address records at the same time.
batch mode operation
[ESRI software] A procedure which uses a given ArcToolbox tool to process a set of information, or batch, rather than applying the tool to one piece at a time. Batch … Read more
batch processing
[ESRI software] A method for processing data automatically in which the data is grouped into batches and executed by the computer at one time, without user interaction.
batch table
[ESRI software] In ArcToolbox, a table which displays the input name, user-selected parameters, and output name, where applicable, for all entries pertaining to a group, or batch, of jobs. Batch … Read more
batch vectorization
[data conversion] An automated process that converts raster data into vector features for an entire raster or a portion of it based on user-defined settings.
bathymetric map
[cartography] A map representing the topography of a seafloor or lake bed, using contour lines to indicate depth.
bathymetry
[cartography] The science of measuring and charting the depths of water bodies to determine the topography of a lake bed or seafloor.
battle dimension
[ESRI software] In MOLE, the primary area in which a force unit operates, such as air, space, ground, sea, surface, and subsurface.
Bayes’ theorem
A theorem developed by English mathematician Thomas Bayes (1702-1761) about conditional probability. It states that the probability of a given event, given the original data and some new data, is … Read more
Bayesian statistics
A statistical approach to measuring likelihood. Bayesian estimates are based on the synthesis of a prior distribution and current sample data. Classical approaches to statistics estimate the probability of an … Read more
bearing method
[ESRI software] In Survey Analyst for field measurements, one of two methods for computing the coordinate geometry traverse. The bearing method uses compass directions for the orientation of each course.
behavior
[ESRI software] The actions or characteristics exhibited by an object in a database, as defined by a set of rules.
best route
[ESRI software] The route of least impedance between two or more locations, taking into account connectivity and travel restrictions such as one-way streets and rush-hour traffic.
Bézier curve
[Euclidean geometry] A curved line whose shape is derived mathematically rather than by a series of connected vertices. In graphics programs, a Bzier curve usually has two endpoints and two … Read more
Bhattacharyya distance
[digital image processing] In digital image processing, a measure of the theoretical distance between two normal distributions of spectral classes, which acts as an upper limit on the probability of … Read more
big endian
[hardware] A computer hardware architecture in which, within a multibyte numeric representation, the most significant byte has the lowest address and the remaining bytes are encoded in decreasing order of … Read more
billboarding
[graphics map display] A method for displaying graphics associated with features in a three-dimensional map display by posting them vertically as two-dimensional symbols and orienting them to always face the … Read more
binary
[computing] In computing, having only two states, such as yes or no, on or off, true or false, or 0 or 1.
binary file
[computing] A file that contains data encoded as a sequence of bits (ones and zeros) instead of plain text. A binary file, such as a DLL or an executable file, … Read more
binding
[programming] In computer programming, the process by which a program discovers an object’s methods and properties.
binomial distribution
[statistics] A distribution describing the probability of obtaining exactly K successes in N independent trials, where each trial results in either a success or a failure.
biogeography
The study of the geographical distribution of living things.
biomass
The total amount of organic matter in a defined area; usually refers to vegetation.
bit depth
[data structures] The range of values that a particular raster format can store, based on the formula 2n. An 8-bit depth dataset can store 256 unique values.
blind digitizing
[data capture] A method of manual digitizing in which the operator has no graphic display on hand with which to see the digitized coordinates as they are captured.
block attribute
[non-ESRI software] In CAD, a collection of objects that can be associated to form a single object.
block group
[federal government] A unit of U.S. census geography that is a combination of census blocks. A block group is the smallest unit for which the U.S. Census Bureau reports a … Read more
block kriging
A kriging method in which the average expected value in an area around an unsampled point is generated rather than the estimated exact value of an unsampled point. Block kriging … Read more
blocking
[ESRI software] In ArcGIS, a geocoding indexing process that reduces the number of potential matches that need to be checked.
blunder
[surveying] In surveying, a defective measurement that can be detected by a statistical test.
Boolean expression
[mathematics] An expression, named for the English mathematician George Boole (1815-1864), that results in a true or false (logical) condition. For example, in the Boolean expression “HEIGHT > 70 AND … Read more
Boolean operation
A GIS operation that uses Boolean operators to combine input datasets into a single output dataset.
Boolean operator
[mathematics] A logical operator used in the formulation of a Boolean expression. Common Boolean operators include AND, which specifies a combination of conditions (A and B must be true); OR, … Read more
border arcs
[data models] The arcs that create the boundary line of a polygon coverage.
boundary effect
A problem created during spatial analysis, caused by arbitrary or discrete boundaries being imposed on spatial data representing nondiscrete or unbounded spatial phenomena. Boundary problems include edge effects, in which … Read more
boundary feature weight
[ESRI software] One of two types of feature weights that allow control of how labels are placed relative to polygon features in ArcMap. Higher feature weights prevent labels from being … Read more
boundary line
[cartography] A division between adjacent political entities, tracts of private land, or geographic zones. Boundary lines may be imaginary lines, physical features that follow those lines, or the graphical representation … Read more
boundary monument
[surveying] An object that marks an accurately surveyed position on or near a boundary.
boundary network
[ESRI software] In Survey Analyst – Cadastral Editor, an irregular mesh of parcel boundaries, connection lines and control points representing a cadastral fabric. A boundary network represents parcels implicitly joined … Read more
boundary survey
1 [cadastral and land records] A map that shows property lines and corner monuments of a parcel of land. 2 [cadastral and land records] The survey taken to gather data … Read more
bounding rectangle
[map display] The rectangle, aligned with the coordinate axes and placed on a map display, that encompasses a geographic feature or group of features or an area of interest. It … Read more
brightness theme
[data models] In 3D Analyst and Spatial Analyst for ArcView 3.x, a grid theme whose cell values are used to vary the brightness of another grid theme. The cell values … Read more
browse graphic
[ESRI software] An image associated with data to provide a general idea of what the service looks like.
buffer
[spatial analysis] A zone around a map feature measured in units of distance or time. A buffer is useful for proximity analysis.
bug
[computing] In computing, a flaw or error in a software program or hardware component that prevents it from performing the way it should.
build parcel
[ESRI software] In Survey Analyst – Cadastral Editor, a cadastral fabric editing command that creates a parcel from construction lines and legal records.
bus
[computing] A set of conductors that provide communications links between the various functional components of a computer, such as memory and peripheral devices.
business table
[ESRI software] In a geodatabase, the spatially-enabled DBMS table that holds the main attribute values of a dataset. A business table with a spatial column is a feature class, and … Read more
button
[programming] A command that executes a function, macro, or custom code when clicked.
byte
[computing] The smallest addressable unit of data storage within a computer, almost always equivalent to 8 bits and containing one character.