H
handles
A tiny square used to mark a selected graphic (non-textual) element at the corners or along the edges. Handles can be dragged with the mouse to move or resize the selected element.
Hangul
Korean alphabetic system of writing created in the fifteenth century.
hanzi
Traditional written Chinese characters which are not strictly tied to the spoken language to the extent that mutually unintelligible Chinese dialects (such as Mandarin, Wu, Hakka, Cantonese) use the same written forms.
hard disk or hard drive
A mechanical, magnetic storage device for computer data and program files. Internal hard disks (sometimes called fixed disk) are mounted inside the computer chassis and so are not removable. An external hard disk is an enclosed unit that is linked to a computer by appropriate connecting cables. Hard disks are much faster and hold much more than a removable floppy disk, but are slower than RAM disks. (See also: floppy disk, RAM disk.)
hardware key
A small device that contains sealed circuitry and is attached to a microcomputer (as through a parallel port) to verify and authorize software and hardware system configuration.
HBS
A method of defining color space, sometimes known as HSV, that combines hue, brightness, and saturation components to produce all colors. An HBS raster set in
The hue-brightness-saturation model uses a six-sided pyramid (or hexcone) with the apex at the bottom to describe the colors. Black is at the point of the hexcone and the purest, most intense colors are at the top of the hexcone. Like the HIS model, on any horizontal slice of the cone, the hue varies as you move around the slice and the saturation increases as you move outward from the center. The HBS model may be more intuitive than the HIS model, because the Brightness factor is at its most intense at 100%, rather than the Intensity factor which is most intense at 50%. (See also: HIS, RGB.)
Heuristic
A computational method that uses trial and error methods to approximate a solution for computationally difficult problems.
HI
See - HyperIndex.
high-boost filter
A process that enhances and sharpens spatial features in a continuously varying raster object. (See also: filtering.)
high-pass filter
A process that enhances and sharpens the boundary edges in the spatial features of a continuously varying raster object. (See also: filtering)
high-order characters
Characters in a computer's 8-bit character set above the standard 128 ASCII characters. High-order characters (also called "extended" characters) are numbered 128-255, and most PC's use the IBM extended character encoding scheme (also called the PC-8 character encoding scheme) for screen display of the high-order characters.
The mapping of the high-order characters to the text-mode character encoding scheme of a particular printer is not standard. In order to see what characters a printer provides for the high-order characters, consult the printer's documentation or generate your own test page. In some application software, in order to get a printer to generate a particular character, you may have to use a different character on the screen.
hiragana
Cursive form of kana.
HIS
Hue, Intensity, and Saturation. Sometimes called HLS, for Hue, Luminance and Saturation. The system of defining video output color from hue, intensity and saturation characteristics. HIS controls are commonly used with color television sets. Most computer displays use RGB (red/green/blue) color mixing information instead.
The hue-intensity-saturation color model uses a double cone (with its greatest circumference at the midpoint of the z-axis) to describe specific colors. On any horizontal slice of the cone, the hue varies as you move around the slice and the saturation increases as you move outward from the center. Intensity is the z-axis of the model. The shades of gray are found along the z-axis, where hue and saturation equal zero. (See also: HBS, RGB.)
histogram
A graph of the number of times a value occurs across a range of possible values. One axis of a raster histogram shows how many times a cell value is found in the raster. The other axis shows the range of possible data values (like 0 to 255 for 8-bit cell values).
home range
The area defined by a swarm of spatial observation events. Classically, the home range is the area defined by wildlife sightings that an animal or community of animals uses under normal conditions. Environmental stresses may cause a preferred home range to shrink, enlarge, or be abandoned.
hot spot
See - symbol hot spot, cursor hot spot.
HPGL
Hewlett Packard Graphics Language. A protocol language used by a number of pen plotters.
hue
One of the three coordinates needed to specify a color in the HBS and HIS color domain. Hue tells the color such as red, blue, or green. (See also: HBS, HIS.)
hydrography
The description and study of bodies of water or their representations on a map.
HyperIndex® or HI
You can retrieve HyperIndexed images and information from the object hierarchy by selecting a feature of interest (or "index area") in the current display image with the mouse. (See also: index area, stack.)
hypsography
Measurement and mapping of the variations in earth surface elevation in reference to sea level, which are often represented by contour lines on maps.