S. No

Methods

Assumptions

Limitations

Suitability

1

NN

-Best local predictor is nearest data point

-Relatively the simplest method

-No error assessment, only one data point per polygon.

-Nominal data from observations

2

IDWA

-Underlying surface is smooth

No error assessment and results depend on size of search window and choice of weighting parameter

-Quick interpolation from sparse data on regular grid or irregular spaced samples

3

MIDWA

-Can accommodate the effect of topographic variation [20]

-Similar to IDWA

-Similar to IDWA

4

KM

-Interpolated surface is smooth. Statistical stationary and the intrinsic Hypothesis.

-Error assessment depends on variogram and distribution of data points and size of interpolated blocks and requires care when modelling spatial correlation structures.

-When data are sufficient to compute variograms, kriging provides a good interpolator for sparse data.

5

TPS

-Underlying surface is smooth everywhere

-Goodness of fit possible, but within the assumptions that the fitted surface is perfectly smooth

-Quick interpolation (univariate or rmultivariate) of digital elevation data and related attributes to create digital elevation models(DEM) from moderately detailed data