EM 1110-2-2907
1 October 2003
Geothermal
Refers to heat from sources within the earth.
Goddard Space Flight
The NASA facility at Greenbelt, Maryland, that is also a Landsat ground
Center (GSFC)
receiving station.
GMT
Greenwich mean time. This international 24-h system is used to
designate the time at which Landsat images are acquired.
GOES
Geostationary Operational Environmental Satellite.
Gossan
Surface occurrence of iron oxide formed by the weathering of metallic
sulfide ore minerals.
GPS--Global Positioning
The GPS is a worldwide satellite navigation system that is funded and
System
supervised by the U.S. Department of Defense. GPS satellites transmit
specially coded signals. These signals are processed by a GPS
receiver that computes extremely accurate measurements, including 3-
dimensional position, velocity, and time on a continuous basis
Granularity
Graininess of developed photographic film that is determined by the
texture of the silver grains.
GRASS--Geographic
GRASS is a product of the U.S. Army Corps of Engineers Construction
Resources Analysis
Engineering Research Laboratories (USACERL) in Champaign, Illinois.
Support System
It is an integrated set of programs designed to provide digitizing, image
processing, map production, and geographic information system
capabilities to its users.
Gray scale
A sequence of gray tones ranging from black to white.
Grid format
The result of interpolation from values of a variable measured at
irregularly distributed points, or along survey lines, to values referring to
square cells in a rectangular array. It forms a step in the process of
contouring data, but can also be used as the basis for a raster format to
be displayed and analyzed digitally after the values have been rescaled
to the 0-255 range.
Ground-control point
A geographic feature of known location that is recognizable on images
and can be used to determine geometric corrections.
Ground range
On radar images, the distance from the ground track to an object.
Ground-range image
Radar image in which the scale in the range direction is constant.
Ground receiving station
Facility that records data transmitted by a satellite, such as Landsat.
Ground resolution cell
Area on the terrain that is covered by the IFOV of a detector.
Ground swath
Width of the strip of terrain that is imaged by a scanner system.
GSFC
Goddard Space Flight Center
H
Refers to waves in which the component frequencies are whole-
number multiples of the fundamental frequency.
HCMM
Heat Capacity Mapping Mission, the NASA satellite launched in 1978 to
observe thermal properties of rocks and soils. It remained in orbit for
only a few months.
Heat capacity-(c)
Ratio of heat absorbed or released by a material to the corresponding
temperature rise or fall. Expressed in calories per gram per degree
centigrade. Also called thermal capacity.
Heat Capacity Mapping
NASA satellite orbited in 1978 to record daytime and nighttime visible
Mission (HCMM)
and thermal IR images of large areas.
Highlights
Areas of bright tone on an image.
High-pass filter
A spatial filter that selectively enhances contrast variations with high
spatial frequencies in an image. It improves the sharpness of images
and is a method of edge enhancement.
HIRIS-High Resolution
Possibly to be carried by the Space Shuttle.
Imaging Spectrometer
HIRS-High Resolution
Carried by NOAA satellites.
Infrared Spectrometer
Glossary-14
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