[remote sensing] Sidelap (or side overlap) consists of the overlapping edge areas of photographs between adjacent flight lines.

 [GIS processing] Skeletonizing is the process of thinning a raster line to a single pixel width, typically for conversion to vector data format.

[editing] The snapping environment in GIS determines the distance that newly digitized points, lines and polygons will occupy the same location of existing features.

Soil data consist of georeferenced digital map data and associated tabular attribute data. The map data describe the spatial distribution of the various soils that cover Earth’s surface. The attribute data describe the proportionate extent of the various soils, as well as the physical and chemical characteristics of those soils. The physical and chemical properties are based on observed and measured values, as well as model-generated values. Also included are model-generated assessments of the suitability or limitations of the soils to various land uses.

Source: OMB Circular A–16: Appendix E (2002)

Category: NSDI Data Themes (NDT)

[data structure] The spaghetti data model is a simple GIS model where lines may cross without intersecting or topology and usually no attributes are created.

The process of modeling, examining, and interpreting model results. Spatial analysis is useful for evaluating suitability and capability, for estimating and predicting, and for interpreting and understanding. 

degree of correlation between a surface value and the values of its neighbors; propensity of spatial data to vary smoothly.

Object used for representing a spatial characteristic of a feature.

a measurement framework that identifies a particular category, then maps the location of that object (as a point, a line or an area).

a mechanism to situate measurements on a geometric body, such as the Earth; establishes a point of origin, orientation of reference axes, and geometric meaning of measurements, as well as units of measure. [basis of coordinates.]

[data structure] A spatial relationship links GIS features with a table by a unique identifier all stored in a relational database management system.

[coordinate system] Spherical coordinates is a coordinate system based on a sphere defined by two angles of rotation in orthogonal planes. The most common is latitudes and longitudes in a geographic coordinate system.

Closed surface that differs only slightly from that of a sphere.