ILWIS data objects (maps, tables and columns) contain references to other objects (e.g. service objects) and to other binary files (e.g. binary data file). All these references are listed in an object's object definition file.
This topic deals with the relations that each object has with other objects by means of the references mentioned above. In the software, these internal relations of one object with other objects are visible as the properties of an object. Any object's properties can be viewed and edited.
ILWIS data objects may also depend on other data objects: when a map is calculated from other maps or when a map is the outcome of an operation on another map. Such relations are called dependency links. For more information, see Basic concepts: Dependent data objects.
In the text below, the word 'use' is used for the references that each object has to other objects. Instead of 'use', you may also read 'have' or 'have a reference to'.
Data objects:
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Raster maps use a domain and a georeference. |
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Polygon maps use a domain and a coordinate system. |
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Segment maps use a domain and a coordinate system. |
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Point maps use a domain and a coordinate system. |
Maps of a domain type Class, ID, or Group may have an attribute table.
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Tables use a domain. |
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Columns use a domain. |
Container objects:
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Map lists contain references to a number of raster maps which use the same georeference and the same domain. |
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Object collections contain references to a number of objects that are included in the object collection. |
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Map views contain references to one or more raster maps, polygon maps, segment maps, and/or point maps and optional annotation text objects. Information on grid lines and graticules is stored in-line. |
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Layouts contain references to one or more map views. Information on annotation is stored in-line. |
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Annotation Text objects have no direct relations with other objects. Annotation text objects are designed to display and store multiple texts at multiple positions. |
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Graphs contain a reference to the table(s) which store the columns that are used in a graph. |
Service objects:
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Domains of the Class, Group, Value and Picture type use a representation. A class, group and picture domain have a representation Class; a value domain has a representation value or a representation gradual. Other domains use 1, 7, 15, or 31 system colors. |
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Representations use a domain. |
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Georeferences use a coordinate system. A georeference tiepoints also uses a background raster map on which you can position your tiepoints. |
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Coordinate systems may contain information on a projection. |
Special objects:
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Histograms are tables. Histograms calculated from images or from existing raster, polygon, segment or point with a Class or ID domain, use the same domain as the map. Histograms calculated from maps with a Value domain, obtain domain None. |
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A sample set uses a map list, a sample set raster map which stores the positions of the training pixels, a domain that contains the class names of training pixels. When your graphics board is configured to use 256 colors, the sample set also uses a background raster map on which you can position your training pixels. |
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A stereo pair contains references to two input raster maps, locations of fiducial marks, principal points, transferred principal points, and optionally scaling points. When calculated, it also contains references to two resampled output raster maps. |
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A criteria tree has no direct relations to other objects. |
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A two-dimensional table uses two domains which contain the classes or IDs that should be reclassified and one domain which contains the classes, IDs or values after reclassification. |
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A matrix has no direct relations to other objects. A matrix is a dependent object, created by the operations Principal Components and Factor Analysis. |
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Filters have no direct relations with other objects. Filters can be applied on raster maps. |
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Functions have no direct relations with other objects. Functions can be used on the command lines, in MapCalc and TabCalc to calculate with maps and/or tables, in scripts, and in the pocket line calculator. |
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Scripts have no direct relations with other objects. Scripts may perform any calculation or operation on any data object, as defined in the script. |
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