Untitled Flashcards Set

Raster

A spatial data model representing geographic phenomena as a grid of equally sized cells, each with an attribute value.

Pixel (Cell)

The smallest unit in a raster grid, storing a single value for the area it represents.

Local Operation

Raster calculation where each output cell value is computed solely from the corresponding input cell(s).

Focal Operation

Also called neighborhood analysis; computes output cell values based on a function applied to a surrounding window of input cells.

Zonal Operation

Aggregates or summarizes input cell values within zones defined by another layer, producing statistics per zone.

Global Operation

Computes output values using information from all cells in the raster (e.g., viewshed, hillshade, distance).

Overlay

The process of combining two or more raster layers cell-by-cell, often using Boolean or arithmetic operators.

Reclassification

Assigning new values to cells based on their original values, typically to group or simplify categories (e.g., land-cover types).

Slope

A global derivative of elevation, measuring the rate of change (steepness) of elevation across neighboring cells.

Aspect

The compass direction that a slope faces, derived from the relative elevation of neighboring cells.

Viewshed

A global analysis identifying which cells are visible from a specified observer location based on elevation.

Hillshade

A shaded relief representation of terrain created by simulating illumination of the surface from a light source at a specified angle and altitude.

Focal Variety

A focal statistic that counts the number of unique cell values within a defined neighborhood around each cell.

Distance

A global or local analysis calculating the Euclidean distance from each cell to the nearest cell meeting a specified condition (e.g., water presence).