top of page

Geospatial and Drone Common Terms


The size of a geographic feature measured in unit squares.

Airbourne LiDAR

In airborne LiDAR, a laser scanner is mounted on an aircraft or helicopter, which scans the ground surface below it with laser beams. The reflected signals are then collected by the scanner and processed to generate 3D point clouds of the terrain.


Altitude is specified relative to either mean sea level (MSL) or an ellipsoid (HAE).


In the context of GIS and mapping, annotation refers to the process of adding labels, symbols, or other text or graphical elements to a map or other spatial data visualization.


ArcGIS is a software platform developed by ESRI (Environmental Systems Research Institute) that allows users to create, manage, analyze, and share geographic data and maps.


A satellite imagery archive is a collection of satellite images that have been collected, processed, and stored.


The compass direction toward which a slope faces, measured in degrees from North in a clockwise direction.


A characteristic of a geographic feature, typically stored in tabular format and linked to the feature in a relational database. 

Attribute Table

A tabular file containing rows and columns. In a GIS, attribute tables are associated with a class of geographic features, such as wells or roads. Each row represents a geographic feature. Each column represents one attribute of a feature, with the same column representing the same attribute in each row.


The horizontal direction of a vector, measured clockwise in degrees of rotation from the positive y-axis, for example, degrees on a compass.


Building Information Modeling (BIM): These days, a growing number of architects, engineers, and contractors are using BIM. BIM is an intelligent model-based process that connects these professionals so they can more efficiently design, build, and operate buildings and infrastructure through information modeling.


Beyond Visual Line of Sight (BVLOS) refers to drone operations where the visual observer responsible for keeping an eye on the drone can’t physically see it during the flight.

Different types of BVLOS  are :

  • Drones flying long distances

  • Drones flying at very high altitude 

  • Drones flying in confined spaces 

  • Drones flying in an area with large obstructions. 


Generic term used to refer to a type of base layer, especially as a reference for onscreen digitizing in GIS.


One layer of a multispectral image representing data values for a specific range of the electromagnetic spectrum of reflected light or heat (e.g., ultraviolet, blue, green, red, near- infrared, infrared, thermal, radar, etc.). Also, other user-specified values derived by manipulation of original image bands. A standard color display of a multispectral image shows three bands, one each for red, green and blue. Satellite imagery such as LANDSAT TM and SPOT provide multispectral images of the Earth, some containing seven or more bands.

Base Layer

A primary layer for spatial reference, upon which other layers are built. Examples of a base layer typically used are either the parcels, or street centerlines.

Base Map

A map containing geographic features that is used for reference. Roads, for example, are commonly found on base maps.


6-digit hydrologic unit delineated for the nation by USGS. Commonly used as a clip boundary.

Bathymetric LiDAR Mapping

Bathymetric LiDAR is used for mapping the underwater topography of the sea or riverbeds. In this method, a Lidar sensor is mounted on a boat or ship, which emits laser beams that penetrate the water surface and reflect back from the seafloor.


A direction from your current position to some other point of interest. Bearings are measured in degrees (360 in a full circle), clockwise from either true or magnetic North. See also heading.

Boolean Expression

A type of expression that reduces to a true or false (logical) condition. A Boolean expression contains logical expressions (e.g., DEPTH > 100) and Boolean operators. A Boolean operator is a keyword that specifies how to combine simple logical expressions into complex expressions. Boolean operators negate a predicate (NOT), specify a combination of predicates (AND), or specify a list of alternative predicates (OR). For example, DEPTH > 100 AND DIAMETER > 20


A zone of a specified distance around a feature


Common land unit. A vector outline of tracts and/or fields. Many CLU polygons make up a coverage. The definition adopted for use in USDA service centers is: “The smallest unit which has a permanent, contiguous boundary, common management or treatment, common owner, or common client association." An example of a CLU might be a CRP field, a fenced pasture, or a strip in a crop/fallow ratio


The Content Standards for Spatial Metadata. A document produced by the Federal Geographic Data Committee (FGDC) that describes spatial metadata.

Cartesian Coordinate System

A two-dimensional, planar coordinate system in which x measures horizontal distance and y measures vertical distance. Each point on the plane is defined by an x,y coordinate. Relative measures of distance, area, and direction are constant throughout the Cartesian coordinate plane.

Central Meridian

A zone constant used when defining a map projection.


The vertical dimension of a table. A column has a name and a data type applied to all values in the column.


A software tool used to reduce the size of large raster files. Compression can be lossless, which preserves image quality, or lossy, which sacrifices some image quality for the sake of greatly reduced file size. Examples include MrSID and JPEG2000.


1. A specific set of satellites used in calculating positions; 3 satellites for 2D fixes, 4 satellites or more for 3D fixes.
2. All of the satellites visible to a GPS receiver at one time. The optimum constellation is the constellation with the lowest PDOP.


A line connecting points of equal surface value.

Contour Interval

The difference in surface values between contours.


An x,y location in a Cartesian coordinate system or an x,y,z coordinate in a three dimensional system. Coordinates represent locations on the Earth’s surface relative to other locations.

Coordinate System

A reference system used to measure horizontal and vertical distances on a planimetric map. A coordinate system is usually defined by a map projection, a spheroid of reference, a datum, one or more standard parallels, a central meridian, and possible shifts in the x- and y-directions to locate x,y positions of point, line, and area features. A common coordinate system is used to spatially register geographic data for the same area.


Terrain elevation data provided in digital form.


Digital Geospatial Metadata. DGM was approved in June 1994 by the Federal Geographic Data Committee (FGDC). DGM describes the specifications for the content, quality, condition, and other characteristics of metadata (data about data). The standard provides a common set of terminology and definitions for the documentation of geospatial data. DGM establishes the names of data elements and groups of data elements to be used for these purposes, definitions of these data elements and groups, and information about the values that are to be provided for the data elements


1. Digital line graph files from the U.S. Geological Survey (USGS), including data from the base map categories such as transportation, hydrography, contours, and public land survey boundaries.
2. The digital format standards published by USGS for exchanging cartographic data files and in which the USGS delivers digital line graph data sets.


Digital orthophoto quadrangle. Digital representation of an aerial photograph or other remotely sensed data that have been rectified to produce an accurate image of the earth by removing tilt and relief displacements which occurred when the photo was taken. Standard USGS format is one quarter of a 7.5' quad. Data is provided at the 1:12000 scale. The DOQ combines the image characteristics of a photograph with the accuracy and scale associated with a map. Typical base layer required for GIS functionality.


Digital Orthophoto Quarter Quad. USGS provides DOQ data in quarter quad format for ease of use and to minimize storage requirements. Four DOQQs may be joined to form a full-quad DOQ.


Digital Raster Graphic. Scanned 1:24,000 scale USGS topographic quad. Can be used as a backdrop and to manually measure distance and obtain location coordinates, but cannot be spatially manipulated.



Digital surface model.


Digital terrain model.


Data Exchange Format. A format for storing vector data in ASCII or binary files. Used by AutoCAD and other CAD software for data interchange. DXF files can be converted to GIS coverages.

Data Conversion

The translation of data from one format to another. GIS software supports data conversion from many geographic data formats such as DLG, TIGER, DXF, and DEM.

Data Dictionary

1. (GIS) A catalog of all data held in a database, or a list of items giving data names and structures. Also referred to as DDID for data dictionary/directory.
2. (GPS) A description of the features and attributes relevant to a particular project or job. This description includes feature names, data type classifications (point, line, area), attribute names, attribute types and attribute values. After being created, a data dictionary can be used to control the capture of features and attributes.

Data Type

The characteristic of columns and variables that defines what types of data values they can store. Examples include character, floating point and integer.


Earth Observation Satellite. An effort to study the earth as a system while tracking long-term changes on a global scale. EOS, a mission of the National Aeronautics and Space Administration (NASA), will produce petabytes (1,000 terabytes) of satellite image data and also large-scale data sets (terabytes [1,000 gigabytes] a day) to be manipulated and analyzed.

Edge Matching

An editing procedure to ensure that all features that cross adjacent map sheets have the same edge locations. Links are used when matching features in adjacent coverages.


In geometric terms, a closed surface of which all planar sections are ellipses. In GIS and mapping practices, an ellipsoid is a specific mathematical representation of the earth that more closely approximates the shape of the surface than a sphere does.


A collection of objects (persons, places, things) described by the same attributes. Entities are identified during the conceptual design phase of database and application design.


The parallel of reference 0 North or South.


Electric Vertical Takeoff and Landing Vehicle (eVOTL):  Most cities do not have the space for a runway to hold electrical flying cars. The way we travel will be changed by the public adoption of eVTOL aircraft.


Federal Aviation Administration 


Federal Geographic Data Committee (FGDC) is the lead entity in the executive branch of government for the development, implementation, and review of policies, practices, and standards relating to geospatial data.


The Federal Information Processing Standards. FlPS deals with a wide range of computer system components including the components of most GISs: hardware, storage media, data files, codes, interfaces, data transmission, networking, data management, documentation, programming languages, software engineering, performance, security, and so forth. FlPS 173 is the precursor to the SDTS (Spatial Data Transfer Standard), which includes standardized definitions for a variety of digital mapping terms and addresses federal requirements for accuracy. FlPS provides a U. S. government standard state and country identification code; standards approved for use by U.S. government agencies. FlPS 152-2 includes POSIX.lcompliance.


Flying First Person View (FPV) makes use of an onboard camera that relays live video to goggles, mobile phone or tablet screen.

Facade Inspection

Building facade inspections are an important part of ensuring the safety and longevity of a building, and they should be performed regularly to identify and address any issues before they become more serious.


In a GIS, a physical object or location of an event. Features can be points (a tree or a traffic accident), lines (a road or river), or areas (a forest or a parking lot).

Feature Attribute Table

A table used to store attribute information for a specific coverage feature class.


The pattern into which data are systematically arranged for use on a computer. A file format is the specific design of how information is organized in the file. DLG, DEM, and TIGER are geographic data sets with different file formats.


All type of map data can be created, managed and analyzed with the help of the system known as GIS (Geographic Information System).


A satellite based device that records x,y,z coordinates and other data. Ground locations are calculated by signals from satellites orbiting the Earth. GPS devices can be taken into the field to record data while walking, driving, or flying.


Geographical Resources Analysis Support System. A public domain image processing and geographic information system (GIS) originally developed by the US Army Corps of Engineers. Software upgrades are currently in development at Baylor University.


The ellipsoid used by the WGS-84 and NAD-83 datums. The best worldwide fit to the geoid.

GeoSpatial Database

A logical collection of interrelated information, managed and stored as a unit. A GIS database includes data about the spatial location and shape of geographic features recorded as points, lines, and polygons as well as their attributes.


The process of identifying a location by one or more attributes from a base layer.


An object-based GIS data model developed by ESRI for ArcGIS that stores each feature as rows in a table. Personal geodatabases store data in a Microsoft Access .mdb file. Corporate geodatabases store data in a DBMS such as SQLserver or Oracle. This data structure supports rules-based topology and allows the user to assign behavior to data.

Geodetic Datum

A mathematical model designed to fit part or all of the geoid (the physical earth's surface). Defined by the relationship between an ellipsoid and a point on the topographic surface established as the orgin of a datum. World geodetic datums are typically defined by the size and shape of the ellipsoid and the location of the center of the ellipsoid with respect to the center of the earth.


The particular equipotential surface which coincides with mean sea level (MSL), and which may be imagined to extend through the continents. This surface is everywhere perpendicular to the force of gravity.


Geometry deals with the measures and properties of points, lines and surfaces. In a GIS, geometry is used to represent the spatial component of geographic features.


To establish the relationship between page coordinates on a planar map and known real-world coordinates

Geospatial Data

Information that identifies the geographic location and characteristics of natural or constructed features and boundaries on the earth. The information may be derived from, among other things, remote sensing, mapping, and surveying technologies.

Heat Map

Heat Map


A graphic representation or description of a scene, typically produced by an optical or electronic device. Common examples include remotely sensed data (e.g., satellite data), scanned data, and photographs. An image is stored as a raster data set of binary or integer values that represent the intensity of reflected light, heat, or other range of values on the electromagnetic spectrum.


Special data structure used in a database to speed searching for records in tables or spatial features in geographic data sets.


The estimation of values of a surface at an unsampled point based on the known values of surrounding points.


The topological integration of two spatial data sets that preserves features that fall within the area common to both input data sets.


A line on a surface connecting points of equal value.


JavaScript Object Notation


Low Altitude Authorization and Notification Capability 


A series of satellites that produce images of the Earth. The Landsat remote sensing satellite program was developed by NASA (National Aeronautics and Space Administration). Landsat data are provided in .BIL (band interleaved by line) or .BIP (band interleaved by pixel) formats.


The north/south component of a location on the surface of an ellipsoid. Latitude is an angular measurement north or south of the equator. Traditionally latitudes north of the equator are considered as positive and those south of the equator as negative.


A logical set of thematic data described and stored in a map library. Layers act as digital transparencies that can be laid atop one another for viewing or spatial analysis.


LiDAR ( Light Detection and Ranging) is a method used for determining distances by targeting an object or area with a laser and measuring the time for the reflected light to return to the receiver. The data colllected is called point data and can also be used to make digital 3-D models of areas on the surface or ocean. 


Lines represent geographic features too narrow to be displayed as an area at a given scale, such as contours, street centerlines, or streams.

MapInfo Pro

A better and more affordable mapping solution for GIS professionals to visualize, edit, interpret, and analyze geospatial data


National Elevation Dataset (NED): The NED is an elevation database created by the United States Geological Survey (USGS). The NED is a collection of the best elevation data.


National Sparial Data Infrastruture 

Ortho Imagery

Aerial photographs that have been rectified to produce an accurate image of the Earth by removing tilt and relief displacements, which occurred when the photo was taken.

Pipeline Mapping

Pipeline mapping is the process of creating a detailed map of pipelines and related infrastructure used for the transportation of liquids, gases, or other materials. This technique is commonly used by the oil and gas industry, as well as other industries that rely on pipelines for transportation.


A single x,y coordinate that represents a geographic feature too small to be displayed as a line or area at that scale.


A multisided figure that represents area on a map. Polygons have attributes that describe the geographic feature they represent

Powerline Mapping

Powerline mapping is the process of creating a detailed map of power lines, poles, and related infrastructure. This technique is commonly used by power companies to manage their assets and maintain their electrical systems.

QGIS Project

QGIS Project


A raster is a digital image representation that uses a grid of pixels to represent an image.