|
|
A |
| |
|
Aerial Image
|
|
Images of the Earth's surface taken from the air with a camera, either hand held or mounted, in an aircraft, helicopter, balloon, rocket, kite, skydiver or similar vehicle. For the purposes of our site, we consider aerial images to be images taken by a craft that is not orbiting the Earth.
|
| |
|
Aeronautical Chart
|
|
A chart that guides pilots in navigating the skies. These charts can show the locations of control towers and radio stations along with the area that their communication devices cover. The may also show navigation aids along the way, alternative landing areas in case of an in-flight emergency, and other useful information such as important radio frequencies and airspace boundaries.
|
| |
|
|
B |
| |
|
Basic Image
|
|
A TerraServer Basic Image contains an image in the JPEG format, along with a World File and a text file that gives basic information about the image such as the UTM zone and image date.
|
| |
|
BBB
|
|
(Better Business Bureau)- The Better Business Bureau was founded in 1912 and has the stated mission to act as a mutually trusted intermediary between consumers and businesses to resolve disputes, to facilitate communication, and to provide information on ethical business practices.
|
| |
|
BLM
|
|
(Bureau of Land Management)- An agency within the United States Department of the Interior which administers America's public lands, totaling approximately 258 million acres (1,060,000 kmē) or one-eighth of the landmass of the country. The BLM has also modified USGS Topographic maps to show land under their management. These maps are available under our Maps tab. For a map of all of the lands under BLM management, please click here.
|
| |
|
BMP
|
|
(Bitmap)- A graphics format used internally by the Microsoft Windows and OS/2 graphics subsystem (GDI), and used commonly as a simple graphics file format on those platforms. These files are usually not compressed.
|
| |
|
Browser
|
|
A software application that enables a user to display and interact with text, images, and other information typically located on a web page at a website on the World Wide Web or a local area network. Web browsers format HTML information for display, so the appearance of a web page may differ between browsers. Common web browsers include Internet Explorer, Mozilla Firefox, Netscape, and Safari.
|
| |
|
|
C |
| |
|
CAD
|
|
(Computer Aided Design)- The use of a wide range of computer-based tools that assist engineers, architects and other design professionals in their design activities. These programs can range from 2D vector modeling to 3D full surface modeling.
|
| |
|
Canvas Paper
|
|
An extremely heavy duty fabric that is used as the medium for oil painting and some types of printing. Modern canvas is made from cotton. Our canvas prints are designed to resemble oil paintings in their finish. They will need to be stretched over a wood frame backing.
|
| |
|
CD
|
|
(Compact Disc)- An optical disc used to store digital data.
|
| |
|
Cloud Cover
|
|
The fraction of the sky covered by clouds in an aerial or satellite image.
|
| |
|
Complete Image
|
|
A TerraServer Complete Image contains an image in the following formats: JPEG, Bitmap, PNG, TIFF, PSD, PDF, GIFF. The Complete File also includes a World File and basic information text file.
|
| |
|
Compression
|
|
Applying data compression to an image to reduce redundancy in the image data in order to more efficiently transmit and store the image.
|
| |
|
Cookies
|
|
Parcels of text sent by a web server to a browser and then sent back to the server unchanged any time that the browser accesses the server. Cookies are used for authenticating, tracking, and maintaining specific information about users, such as site preferences and the contents of their electronic shopping carts.
|
| |
|
Coordinates
|
|
A set of numbers that define the position of some object in reference to a reference point or origin on coordinate plain. On the Earth, these numbers define the location of any point on Earth in reference to a geographical coordinate system.
|
| |
|
|
D |
| |
|
Datum
|
|
A reference from which measurements are made. In georeferencing, a datum is a point on the Earth's surface from which surface measurements are made.
|
| |
|
Degrees
|
|
A measurement of circular plane angle in reference to a meridian that indicates position along a great circle on a sphere. The Earth is divided into 360 degrees.
|
| |
|
DEM
|
|
(Digital Elevation Model)- A digital representation of ground surface topography or terrain. DEMs are often used in GIS and are usually developed using remote sensing techniques. They are also known as Digital Terrain Models (DTM).
|
| |
|
Domain Name
|
|
A name that identifies a computer on the internet and appears in the URL. The Domain name is often more memorable and stands in for the numeric IP address. They also allow mobility in that they do not have to change if the company moves and changes their IP address.
|
| |
|
DOQ
|
|
(Digital Orthophoto Quadrangle)- A digital mapping product that combines the geometric qualities of a map with the detail of an aerial photograph. DOQs are digitally derived aerial photos that have been corrected so image distortion caused by perspective, camera tilt, and terrain relief are removed. Distances, bearings, and area calculations can all be measured on DOQs. Also known as Digital Orthophoto Quarter Quadrangle (DOQQ), which is one quarter of a standard DOQ
|
| |
|
DVD
|
|
(Digital Video Disc)- An optical disc used to store digital files and media with a single layer capacity of 4.7 GB
|
| |
|
|
E |
| |
|
Easting
|
|
A measurement used in the UTM coordinate system that measures the distance East of a point from the central meridian of a zone. The central meridian is given a false easting value of 500,000 so that there are no negative numbers. Any point west of the meridian will have a value less than 500,000 and any point east will be greater.
|
| |
|
|
F |
| |
|
FAA
|
|
(Federal Aviation Administration)- An agency of the United States Department of Transportation with authority to regulate and oversee all aspects of civil aviation in the United States. Their tasks include regulating civil and commercial air traffic, operating a system of air traffic control, and carrying out programs to reduce noise and environmental pollution caused by aviation.
|
| |
|
False Color
|
|
An image that depicts a subject in colors that differ from human perception of the same subject. This can include infrared thermal imagery.
|
| |
|
FAQ
|
|
(Frequently Asked Questions)- An assembled list of questions and answers that are considered common about a certain topic.
|
| |
|
Favorite
|
|
TerraServer uses a Favorite feature so that subscribers can store their favorite images to a page so that they can be accessed anytime. Subscribers can go to their Favorites page and access this imagery whenever they would like.
|
| |
|
FEMA
|
|
(Federal Emergency Management Agency)- an agency of the United States Department of Homeland Security who purpose is to coordinate the response to a disaster which has occurred in the United States and which overwhelms the resources of local and state authorities. FEMA also keeps track and records natural disasters that occur within the United States. FEMA data is the basis for many of the overlays available to TerraServer subscribers
|
| |
|
Flood Plain
|
|
A flat or nearly flat land adjacent to a stream or river that experiences occasional or periodic flooding. It includes the floodway, which consists of the stream channel and adjacent areas that carry flood flows, and the flood fringe, which are areas covered by the flood, but which do not experience a strong current.
|
| |
|
|
G |
| |
|
Geo-reference
|
|
The process of defining the position of something in space with respect to Earth. This process is carried over to imagery in that the corner points and center point of the image must be defined with respect to the Earth.
|
| |
|
Geographic Projection
|
|
A very simple map projection which is characterized by equidistant meridians and parallels. Also known as equarectangular projection.
|
| |
|
Geospatial
|
|
A term widely used to describe the combination of spatial software and analytical methods with terrestrial or geographic datasets. The term is often used in conjunction with geographic information systems and geomatics. In the case of vector-based GIS this typically means operations such as map overlay (combining two or more maps or map layers according to predefined rules), simple buffering (identifying regions of a map within a specified distance of one or more features, such as towns, roads or rivers) and similar basic operations.
|
| |
|
GIF
|
|
(Graphics Interchange Format)- An 8-bit-per pixel image format that is in wide use on the web and is used widely for basic animation. The 256 color palette for GIF images does not make it very good at reproducing photographs.
|
| |
|
Gigabyte
|
|
A unit of computer storage equal to one billion bytes.
|
| |
|
GIS
|
|
(Geographic Information System)- A computer system capable of allowing users to import, integrate, analyze, and display geo-referenced data. GIS is different from topography in that it can be used to depict and analyze geographically dependent phenomena.
|
| |
|
Glossy Paper
|
|
A paper type that maintains a high ability to reflect light in the specular direction. This type of paper finish is similar to the finish on conventional photography.
|
| |
|
GPS
|
|
(Global Positioning System)- The only fully functional Global Navigation Satellite System. GPS was developed by the United States Government and is a public good that is free for civilian use, despite an annual cost over $750 million. GPS coordinates are generally based on Latitude and Longitude. These coordinates are provided by receiving signals from at least three satellites and then using trilateration to determine a position.
|
| |
|
|
H |
| |
|
Hyperspectral
|
|
The collection of imagery using a vast portion of the light spectrum, beyond visible light. Different elements within the image leave different marks in each of the various bands of the spectrum. By analyzing these marks, one can determine the identity of objects in the image that would not be possible with conventional imaging.
|
| |
|
|
I |
| |
|
IKONOS
|
|
The first high resolution commercial satellite to make imagery of the Earth publicly available at 1 and 4 meter resolution.
|
| |
|
Image Compression
|
|
The application of data compression on imagery. The object of compression is to reduce redundancy within the image file in order to make transmission and storage more efficient.
|
| |
|
Image Date
|
|
The date or approximate date that an image was taken. Since images of a large area can occur over multiple days based on weather conditions and the size of the area, a group of images may all be assigned a specific date near to the date that they were taken.
|
| |
|
Image Download
|
|
The transfer of image files from a host server onto a user's computer. Once the files are downloaded, they are contained on the computer's hard drive until they are removed by the user.
|
| |
|
Infrared
|
|
Energy emission of a wave length longer than that of visible light. Infrared radiation can be used to determine the surface temperature of an object.
|
| |
|
IP Address
|
|
(Internet Protocol Address)- A unique address that certain electronic devices utilize to communicate and identify each other when part of a computer network.
|
| |
|
|
J |
| |
|
JPEG
|
|
(Joint Photographic Experts Group)- A commonly used standard method of compression for digital images. JPEG refers to both the file format and the codec, which defines how the image is broken down into bytes and then rebuilt into an image.
|
| |
|
|
L |
| |
|
Laminated Paper
|
|
A process through which an image is printed and then covered with a thin plastic film. This film will allow wet and dry erase markers to be used on the image.
|
| |
|
LandSat
|
|
The longest running enterprise for the acquisition of imagery of Earth from space. The first satellite was launched in 1972 while the most recent launch was in 1999. The resolution of LandSat images ranges from 60 meters to 15 meters.
|
| |
|
Landscape
|
|
A page layout in which the horizontal edge is longer than the vertical edge.
|
| |
|
Latitude
|
|
A number that gives the location of a place on Earth north or south of the Equator. This number is given in degrees. In some cases, this number is broken down into degrees, minutes, and seconds, where a minute is one sixtieth of a degree and one second is one sixtieth of a minute. A negative value for the degree indicates that the location is south of the Equator.
|
| |
|
LIDAR
|
|
(Light Detection And Ranging)- An optical remote sensing technology in which light emission is measured and used to determine distance, shape, and other properties of a distant object. This can be done in a passive mode in which only output light from other objects is measured or in an active mode in which lasers or light are output by the apparatus and then the time delay between emission and reception of the reflected signal is used to calculate information about the target. This is very similar to RADAR except that RADAR uses sound where as LIDAR uses light.
|
| |
|
Longitude
|
|
A number that gives the location of a place on Earth east or west of the Prime Meridian. This number is given in degrees. In some cases, this number is broken down into degrees, minutes, and seconds, where a minute is one sixtieth of a degree and one second is one sixtieth of a minute. A negative value for the degree indicates that the location is west of the Prime Meridian.
|
| |
|
|
M |
| |
|
Matte Paper
|
|
A paper type that does not reflect a large amount of light. This finish is very similar to the finish found on common road maps.
|
| |
|
Megabyte
|
|
A unit of computer storage equal to one million bytes.
|
| |
|
Minutes
|
|
In the sense of geography, a subdivision of a degree that is equal to one sixtieth of a degree.
|
| |
|
Multi-Spectral
|
|
An imaging technology that can capture light from frequencies beyond the visible light spectrum, such as infrared and electromagnetic.
|
| |
|
|
N |
| |
|
NAD83
|
|
The North American Datum as established in 1983. This datum is the result of increases in technology in regards to remote sensing and is based on the GRS80 Ellipsoid.
|
| |
|
NAIP
|
|
(National Agriculture Imagery Program)- Acquires imagery during the agricultural growing seasons (spring and summer months for leaf-on coverage) in the continental U.S.
|
| |
|
NAPP
|
|
(National Aerial Photography Program)- An interagency Federal effort coordinated by the USGS to obtain aerial imagery of the entire contiguous United States and Hawaii. These images are shot from 20,000 feet with a focal length of 6 inches.
|
| |
|
Natural Color
|
|
Color as seen by the human eye. Composed of six unique colors and combinations of these colors.
|
| |
|
NED
|
|
(National Elevation Dataset)- A seamless set of data giving the elevation of the entire United States and all island territories composed by the USGS.
|
| |
|
NOAA
|
|
(National Oceanic and Atmospheric Administration)- A scientific agency under the Department of Commerce that focuses on the conditions of the of the ocean and the atmosphere. NOAA is responsible for charting both the sea and skies in addition to monitoring atmospheric and oceanic conditions.
|
| |
|
Northing
|
|
The distance from the Equator when using UTM Coordinates. When in the northern hemisphere, the value at the Equator is zero and increases to 9,328,000 at the 84th Parallel. When in the southern hemisphere, the value at the Equator is given a false northing of 10,000,000 and anywhere south is a smaller number. This is done so that no northing coordinate is zero.
|
| |
|
NWS
|
|
(National Weather Service)- One of the six agencies that makes up NOAA. The mission of the NWS is to provide "weather, hydrologic, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy."
|
| |
|
|
O |
| |
|
Operating System
|
|
A set of computer programs that manage the hardware and software resources of a computer system. Common operating systems include Microsoft Windows, Linux, Unix, and Mac OS.
|
| |
|
Orbit
|
|
The path of an object as it circles another object due to a centripetal force, usually gravity. The Laws of Planetary Motion state that these orbits are in fact elliptical, rather than circular.
|
| |
|
OrbView
|
|
An imaging satellite operated by the GeoEye company.
|
| |
|
Orthographic
|
|
The representation of a three dimensional object in two dimensions. A flat map is an orthographic projection of the world.
|
| |
|
Orthorectified
|
|
The process of manipulating imagery that was taken at an angle other than perpendicular to the Earth's surface so that it appears as if it was taken at a right angle with respect to the surface in terms of the geographic information associated with the image. This process allows the images to be lined up and joined into one larger seamless image.
|
| |
|
Overlay
|
|
A semi-transparent layer placed over an image that provides information related to the image. An overlay can be as simple as the road names over the roads and can be as complex as highlighting all areas that may be subject to a natural disaster, such as floods or landslides.
|
| |
|
|
P |
| |
