What does 'interpolate' mean in GIS?

In the context of GIS, interpolating refers to the method of estimating unknown values at specific locations within a dataset based on known values from surrounding data points. This is particularly useful when working with spatial data that is sampled at specific intervals, such as elevation points, temperature readings, or pollutant concentrations. By utilizing interpolation techniques, GIS can create a continuous surface or map that represents variable changes across a geographic area.

For example, if you have temperature readings from several weather stations in a region, you can use interpolation to estimate the temperature at locations between these stations, where no direct measurements were taken. This allows for a better understanding of spatial phenomena and helps in predicting conditions in areas where data may be sparse. Interpolation techniques employed in GIS include methods like Kriging, IDW (Inverse Distance Weighting), and spline, each suitable for different types of data distributions and shapes.