GIS Dictionary

[uncertainty] In GIS, a state of uncertainty in data classification that exists when an attribute applies to an indeterminate quality of an object or describes an indefinite quantity. For example, … Read more

[ESRI software] In coverages, the number of arcs that begin or end at a node.

[ESRI software] A table that lists the nodes in a data layer along with their valencies.

[ESRI software] A component of the PLTS knowledge base that contains the valid attribute combinations and rendering information for the features in a feature class. VVTs are used to symbolize … Read more

1 [software] The process, using formal methods, of evaluating a system or software component to determine whether it functions as expected and achieves the intended results. 2 [data quality] The … Read more

[data quality] A rule applied to objects in the geodatabase to ensure that their state is consistent with the system that the database is modeling. The geodatabase supports attribute, connectivity, … Read more

1 [mathematics] A measurable quantity that may be passed to a function. Values are either assigned or determined by calculation. 2 [graphics computing] The lightness or darkness of a color. … Read more

1 [mathematics] A symbol or placeholder that represents a changeable value or a value that has not yet been assigned. 2 [computing] A symbol or quantity that can represent any … Read more

[spatial analysis] A drawing technique for hiding part of one layer using another set of features. Variable depth masking allows a layer to be drawn with gaps at specific locations … Read more

[statistics] A numeric description of how values in a distribution vary or deviate from the mean. The larger the variance, the greater the dispersion of values around the mean. The … Read more

[surveying] In surveying, the symmetric 3×3 matrix that mathematically expresses the correlation between errors in coordinates x, y, and z.

[data structures] A data type that can contain any kind of data.

[spatial statistics use for geostatistics] A function of the distance and direction separating two locations that is used to quantify dependence. The variogram is defined as the variance of the … Read more

[spatial statistics use for geostatistics] The process of examining spatial dependence using a variogram; a set of procedures (as much art as science) for interpreting variograms.

[ESRI software] Acronym for value attribute table. A table containing attributes for a grid, including user-defined attributes, the values assigned to cells in the grid, and a count of the … Read more