I
icon
A stylized representation of an object that consists of an image and a label. A window icon is a minimized representation of a window or window family used to help organize windows and tasks in the display. Iconifying a window changes nothing about the state of the active process in the window.
ideograph
A symbol that represents meaning without indicating pronunciation. Often opposed to "phonetic." Chinese is often, but erroneously, called an ideographic language. Its origins (like those of Western alphabets) were ideographic and pictographic, but it is more accurately described as a "morphosyllabic:" a combination of syllabic characters with nonphonetic techniques, such as determinatives, to suggest the meaning category of written items.
IDIMS
A minicomputer, raster-based image processing system originally developed by NASA and more recently maintained and sold by TRW.
IGDS
Interactive Graphics Design Software. Intergraph IGDS file formats can be converted to and from ARC/INFO coverages.
IGES
Initial Graphics Exchange Specification (IGES) is a common data format used for transfer of CAD Data. IGES files can be converted to and from ARC/INFO Coverages.
image
Any analog or digital two-dimensional array of values whose spatial interconnections convey useful information. Image has a wider sense than photographs, TV, or human vision. A photographic print is an image but an image is not necessarily a photograph. What a human sees can be called an image but image is not restricted to describing human vision. The raster scan of a color map is an image until it is reduced to a vector object. However, the display of a vector object on the monitor creates an image of that vector file. Properly, that which is stored in a raster object can be called an image, but that which is stored in vector, text, or database objects cannot.
image map or georeferenced image map
An image that has been processed to be like a map in appearance, scale, geometry, boundary, and projection with a degree of precision that satisfies the user. Measurements made from an image map yield results equal to those made from the corresponding planimetric, topographic, or other map. Similarly, either the image map or the conventional map can be overlaid and matched with the other.
Index
Special data structure used in a database to speed search records in tables or spatial features in geographic data sets.
index areas
The regions in a HyperIndex parent object linked to a daughter object, which may be rectangular, circular, or quadrilateral in shape. HyperIndex will display the daughter object when the mouse selects a point within the index area. Active index areas can be revealed on the display of the parent object when the option "Show Index Areas" under the View window menu HyperIndex is on. (See also: daughter object, link, parent object.)
INFO
The database program used by ARC/INFO. (See also: ARC/INFO.)
intensity
One of the three coordinates needed to define a color in the HIS color domain. Intensity represents a color's brightness or average radiance level. Intensity data is very similar to the information in black and white representations of color images. (See also: HIS)
interactive line-following
The Interactive Line-Following process lets you interactively trace easily distinguishable lines in a RGB, or color separated, type raster object and create vector (or CAD) elements with minimal guidance.
interface
The type of signal protocol for connecting computer devices. You can only connect a peripheral device to a microcomputer through a matching interface. Common interface types include serial, parallel, SCSI and GPIB.
interface board or interface card
Any electronic circuit board installed in a microcomputer that handles translation between the computer and some particular hardware device. For example, an interface board may translate output data into display signals for an image display monitor, or translate input signals from a color scanner into digital data for the computer.
interlaced video
Background: The image you see on a TV screen is made from a set of about 480 horizontal lines. The lines are projected in two passes of the signal beam. Each pass only projects every other line of the image: the odd lines in one pass, and the even lines in the next pass. One scan takes 1/60 of a second, so the whole picture (the frame) is refreshed every 1/30th of a second. There is a time difference of 1/60 of a second between any pair of adjacent lines in a frame.
Thus, a single, still video image of 1/30 of a second duration consists of two inrlaced fields of the source video signal. Displaying a single frame of interlaced video causes vertical jitter. This jitter is especially pronounced when an image contains horizontal lines. This is called umpire shirt jitter on conventional broadcast TV and can be seen along the black and white edges of an umpire's shirt or along the sharp horizontal edges of large letters. This effect can cause eye strain. Interlace jitter is best overcome by using a monitor with long-persistence phosphor. This phosphor holds each line longer until it can be refreshed by the next scan.
internationalized X application
A program for the X Window System that is not "hard wired" to any specific language or culture, and so is capable of operating using a single user-selected language and set of cultural conventions. Internationalization supports implementation in one target language, and thus stops short of full multilingual support.
interpolation
Applying mathematical estimation techniques to sets of numbers to find intermediate values. Interpolation is a collective term for various techniques of determining an approximate value of a function at a point in the domain between given points at which the function values are known. Bilinear interpolation, for example, is based on the presumption that the value being sought lies on or near a straight line joining two known values. (See also: convolution.)
interpretation
Identifying and grouping classes of features in an image. In a fully interpreted image, every pixel is assigned to a class. In many cases, partial interpretation is adequate, such as just showing cultivated land, or just showing wetlands.
interpreted programming language
(as opposed to a compiled language) A computer language that is evaluated and executed by the system one command or statement at a time. By contrast, a program in a compiled language is completely evaluated and translated into machine code by the system before any of it is executed.
Intersect
The topological integration of two spatial data sets that preserves features that fall within the spatial extent common to both input data sets.
ISA
Industry Standard Architecture. One of the standard bus architectures for microcomputers. (See also: bus.)
ISI
A manufacturer of WORM drives.
ISO
International Organization for Standardization. The ISO defines and publishes standards that can be adopted by many manufacturers. For example, one ISO standard defines the format for erasable optical disks, so they can be used on drives from any manufacturer that supports the standard.
ISO 10646
A character encoding scheme that is a super set of the ASCII, Latin-1, and Unicode character sets that has room for 4,294,967,296 characters (a 32-bit or 4-byte character encoding scheme). Ultimately, ISO 10646 will assign codes to every known symbol and character of both modern and ancient languages.
Isopleth map (Isoline)
A map displaying the distribution of an attributes in terms of lines connecting points of equal value.
item
Anything that can be placed on the page in the page layout design process, including rasters, vectors, CAD objects, text files, scale bars, and tick marks. The page layout process provides tools to select, size, and position items.