GIS Glossary

American Standard Code for Information Interchange (ASCII) : A file format for storing and exchanging spatial and attribute data in plain text.

The x-coordinate in a rectangular coordinate system, critical for defining spatial positions.

The degree to which a measured or calculated position matches its true value, important for spatial data reliability.

Coordinates that specify a location in a fixed, global reference system, such as latitude and longitude.

The difference in elevation between the highest and lowest points in an area, relevant for terrain analysis

The closeness of a measurement or spatial data value to its true value, crucial for all spatial analysis (inferred from standard GIS usage).

The process of evaluating the correctness of spatial data, especially in classification and remote sensing (inferred from standard GIS usage).

The use of sensors that emit energy and measure its reflection from the earth’s surface, important for spatial data collection.

Images of the earth taken from aircraft, used as a source of spatial data for analysis and mapping (inferred from standard GIS usage).

The process of combining multiple features or data values into a summary form, often used in spatial statistics (inferred from standard GIS usage).

The process of examining spatial data to discover patterns, relationships, or trends, central to GIS applications.

Text or graphics added to maps to provide additional information about spatial features (inferred from standard GIS usage).

A line segment defined by its endpoints (nodes), fundamental in vector data models for representing linear features.

A scripting language used for automating GIS tasks, particularly in ESRI software

A widely used GIS software suite by Esri for spatial data management, analysis, and visualization (inferred from standard GIS usage).

The size or extent of a polygon feature, a basic spatial measurement used in many analyses.

The compass direction that a slope faces, measured in degrees; important for terrain and environmental analysis.

The process of mapping the locations and characteristics of physical assets, supporting spatial inventory and management.

A characteristic or property of a spatial feature, such as population or land use, stored in a table linked to spatial data.

A map projection that transforms points from a sphere onto a plane, used for certain spatial analyses and visualizations.

Foundational variables used in spatial analysis, often as reference or control variables in statistical modelling.

A georeferenced background image or map layer that provides context for other spatial data and analysis. It serves as a reference framework for overlaying thematic data.

A statistical method used in spatial analysis to update the probability of a hypothesis based on observed data, relevant for spatial modelling and prediction.

The direction from one point to another, measured as an angle from a reference direction (usually north). Bearings are important in navigation and spatial orientation.

A precisely surveyed point, often marked physically, used as a control point for spatial data collection and accuracy assessment.

A raster data format where each cell is coded with only two possible values(e.g., 0 or 1), often used for presence/absence or suitability analysis (inferred from standard GIS usage).

The smallest rectangle, aligned with coordinate axes, that completely contains a geographic feature or set of features. Useful for spatial queries and map display extents.

Linear features representing a change in the slope or elevation in terrain modelling, important for creating accurate digital elevation models (inferred from standard GIS usage).

A spatial analysis operation that creates zones of a specified distance around geographic features (points, lines, or polygons). Buffers are commonly used to analyse proximity and impact areas.

The process of creating and analysing buffer zones to assess spatial relationships and impacts, such as identifying features within a certain distance of a point or line.

Relating to land boundaries and subdivisions; cadastral data is essential for property and land management analysis.

The ratio between distances on a map and actual ground distances, influencing spatial analysis resolution.

The art and science of map-making, fundamental for visualizing and interpreting spatial data.

The process of grouping spatial data into categories based on attribute values, essential for thematic mapping and analysis.

A spatial operation that extracts features from one dataset that fall within the boundaries of another, commonly used to focus analysis on a specific area.

A statistical method for identifying spatial groupings or concentrations of features, widely used in spatial pattern analysis.

A gradient of colors used to represent data values on a map, aiding in the visualization of spatial analysis results.

A map created by overlaying multiple spatial data layers, supporting complex spatial analysis

Digital design data often integrated into GIS for spatial analysis of infrastructure and engineering features.

The spatial relationship describing how features are linked or connected, critical in network and hydrological analyses.

Data that varies smoothly across a surface, such as elevation or temperature, requiring specialized spatial analysis techniques.

A line connecting points of equal elevation, used in terrain analysis and visualization.

A known geographic location used to align spatial datasets accurately, crucial for georeferencing and spatial accuracy.

A set of values (x, y, and sometimes z) that define a location in space, foundational for all spatial data analysis.

Mathematical methods for defining spatial features using bearings and distances, important in surveying and spatial calculations.

A reference framework used to define the positions of features in space, ensuring spatial data from different sources aligns correctly.

The process of converting spatial data between different coordinate systems, ensuring data compatibility.

A vector data model for storing geographic features and their attributes, often used in spatial analysis workflows.

A table storing attribute data for features in a coverage, supporting attribute-based spatial analysis.

A polygon feature within a coverage data model, representing area-based spatial entities.

A visual interface that displays spatial data and analytics for real-time monitoring and decision-making.

A method for improving thematic mapping accuracy by using ancillary data to refine the spatial distribution of data values.

The fundamental building blocks in GIS, representing facts, figures, or spatial information ready for processing and analysis.

The degree to which spatial data correctly represents real-world features, crucial for reliable analysis.

Grouping spatial data into discrete cells or bins for statistical analysis and visualization.

The process of translating data from one format to another, ensuring compatibility for spatial analysis.

A column in a data table representing a specific attribute, essential for organizing and analysing spatial data.

A collection of related GIS data tables or layers, often analysed collectively to extract spatial patterns.

Software used to store, retrieve, and manage spatial and attribute data, supporting complex spatial queries and analyses.

A mathematical model that defines the reference for geographic coordinates, ensuring spatial data from different sources aligns correctly.

The use of GIS and visualization to aid decision-makers in interpreting and analysing spatial data for planning and management.

The vertical distance from a reference surface, often used in hydrological and subsurface analyses.

A raster dataset representing the earth’s surface elevation, widely used in terrain analysis and hydrological modelling.

A digital vector data format used for representing features such as topography and hydrography, important for spatial analysis of physical landscapes.

Similar to DEM but includes the elevation of buildings, vegetation, and other objects above the ground, useful for urban and environmental analysis.

A refined DEM that incorporates key topographic features, enabling detailed surface analysis.

A spatial reference system that partitions the globe into hierarchical cells for efficient spatial analysis and data management.

A technique for associating multiple sets of attributes with portions of linear features, allowing for advanced event mapping along routes (e.g., roads, rivers).

In network analysis, a line or segment representing a connection between nodes, such as a road segment (standard GIS usage).

The property of a network describing how edges (connections) link nodes, critical in network and flow analysis (standard GIS usage).

Distortion or bias in spatial analysis results near the boundaries of a study area (standard GIS usage).

The process of aligning features (such as lines or polygons) at the boundaries of adjacent map sheets or datasets (standard GIS usage).

The height of a geographic location above a reference point, usually mean sea level; essential for terrain analysis and modelling (standard GIS usage).

A digital representation of terrain elevations, such as a Digital Elevation Model (DEM), used in surface and hydrological analysis (standard GIS usage).

The process of converting spatial or attribute data into a digital format for storage and analysis (standard GIS usage).

A real-world object or feature represented in GIS as a point, line, or polygon, such as a hospital, river, or state border.

The minimum bounding rectangle that encloses a spatial feature or dataset, used for spatial queries and extent definition (standard GIS usage).

Spatial data relating to natural features, conditions, or processes, such as land cover, climate, or pollution (standard GIS usage).

A map projection that preserves distances from the center or along specific lines, important for certain spatial analyses (standard GIS usage).

The difference between measured or calculated values and the true values, important for assessing data quality (standard GIS usage).

A table used to assess the accuracy of classified data, especially in remote sensing and land cover analysis (standard GIS usage).

A leading GIS software company, whose tools (like ArcGIS) are widely used for spatial data analysis.

The straight-line distance between two points in space, commonly used in proximity analysis (standard GIS usage).

A spatial occurrence or phenomenon recorded in GIS, often used in event mapping or dynamic segmentation (standard GIS usage).

A GIS layer created from tabular data containing location information, often used for mapping incidents or observations (standard GIS usage).

The process of saving spatial data or analysis results in a different format for use in other applications (standard GIS usage).

The geographic area covered by a dataset or map, defined by minimum and maximum coordinates; crucial for setting analysis boundaries (standard GIS usage).

Estimating values outside the range of observed data, often used in spatial prediction and modelling (standard GIS usage).

In topology, a polygonal area bounded by edges, important in advanced spatial modelling (standard GIS usage).

In 3D GIS, a flat surface that forms part of the boundary of a solid object, important in terrain and surface modelling (standard GIS usage).

Arbitrary values added to x or y coordinates in a projected coordinate system to avoid negative numbers, important for map projections.

A spatial object in GIS, such as a point, line, or polygon, representing real-world entities like buildings, roads, or lakes. Features are the primary units of analysis in vector data models.

A collection of similar features (all points, all lines, or all polygons) stored together, often used as a basic organizational unit in spatial databases (standard GIS usage).

The process of identifying and digitizing features from imagery or other data sources for spatial analysis (standard GIS usage).

A GIS layer that displays and allows analysis of features from a feature class, enabling visualization and spatial queries (standard GIS usage).

A column in an attribute table that stores specific information about each feature, such as population or land use type. Fields are crucial for querying and analysing spatial data.

A process that modifies spatial data or images by emphasizing or suppressing certain features, often used in raster analysis (standard GIS usage).

A raster dataset where cell values are stored as floating-point numbers, allowing for continuous data representation such as elevation or temperature(standard GIS usage).

The calculation of how much flow accumulates in each cell of a raster, used to identify drainage patterns and stream networks (standard GIS usage).

In hydrological analysis, the direction water will flow out of each cell in a raster DEM, foundational for watershed and stream network modelling (standard GIS usage).