Isarithmic map

An isarithmic map represents a continuously varying geographic value with contour lines or bands. Its patterns show estimated values between measured locations as well as values at them.

Isopleth: A line joining points of equal value on a map. Isopleths are the lines that connect equal values in the line-based form of an isarithmic map.
Kriging: A geostatistical interpolation method that predicts values using spatial covariance. Kriging can estimate the continuous surface from which isarithmic contours are drawn.
Topographic map: A map showing landforms and elevation, commonly with contour lines. Topographic maps use elevation isarithms to depict terrain shape.
Dasymetric map: A map that redistributes area-based data using ancillary information to show more plausible internal variation. It refines values within zones rather than deriving contours from a continuous measured field.
Contour line: A line on a map joining locations with the same measured value. Contour lines trace one selected value across an isarithmic map.
Inverse distance weighting: An interpolation method that weights nearby observations more heavily than distant ones. It is a common way to estimate values between sampled locations before contouring.
Isotherm: A line connecting locations with the same temperature. Isotherms are a familiar isarithmic representation of temperature fields.
Dot distribution map: A map that uses dots to show the spatial distribution of discrete quantities or events. Dots preserve discrete counts instead of implying values continuously between locations.
Interpolation: A method for estimating values between known data points. Interpolation supplies the unmapped values needed to draw continuous contours or bands.
Triangulated irregular network: A surface model built from nonoverlapping triangles whose vertices are sampled points. A triangulated surface provides one route from point observations to contour lines.

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