Raster Data Operations

These flashcards cover key concepts from raster data operations including definitions of terms and explanations of operations associated with raster layers.

Precipitation

The average amount of precipitation, typically measured in cm per day.

NDVI

Normalized Difference Vegetation Index, a method to quantify vegetation greenness and assess plant health.

Color Depth

The number of unique colors that a sensor can capture; for example, 16 bits allows approximately 65,000 colors.

Raster data

A model where raster cells store data and can represent values such as pollutants, crop yields, or disease spread.

Local operations

Raster output where cell values are determined by that cell's corresponding input value.

Focal operations

Raster output where cell values depend on the input value at that cell and its neighbors.

Zonal operations

Output values depend on input cell values and their association within defined zones.

Global operations

Output values potentially rely on all input raster cell values.

Map algebra

Combination of raster data layers using cell-by-cell operations such as addition and subtraction.

Mathematical operations

Cell-by-cell operations applied to raster data.

Comparison: less than

A true or false assignment based on whether a cell value is less than another.

Comparison: equal

A true or false assignment based on whether cell values are equal.

Logical Operation: AND

A logical operation that outputs true only if both input values are true.

Logical Operation: OR

A logical operation that outputs true if at least one of the input values is true.

Conditional operations

Operations that evaluate a condition and return one of two possible expressions based on the result.

Complex statements

Expressions where only the output to the left of the equals sign is a Raster object, influenced by operator precedence.

Slope

The rate of change of elevation in a digital elevation model (DEM) cell.

Aspect

Identifies the downslope direction of the maximum change in value from each cell to its neighbors.