The document discusses spatial interpolation techniques. Spatial interpolation is the process of using points with known values to estimate values at other points, turning raw data into useful information by adding context and values. It can predict unknown values for geographic point data like elevation, rainfall, or chemical concentration. Common uses of spatial interpolation in GIS include calculating properties of a surface at given points, providing contours for graphical displays, and aiding in spatial decision making like terrain analysis and hydrology. Interpolation methods can be classified as global or local, exact or approximate, stochastic or deterministic, and abrupt or smooth.

1. Spatial
Interpolatio
n
Techniques
Presenter : GOPAL S Chhetri
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2. What is Spatial Interpolation?
 It is the process of using points with known values to estimate
values at other points.
 Turns raw data into useful information by adding greater
informative content and vales.
 Reveals patterns, tends which is been missed.
ELEMENTS OF SPATIAL INTERPOLATION 17489318

3. Why interpolate to raster?
 Visiting every location in a study areas to measure the height
,magnitude or concentration of a phenomenon is usually
difficult or expensive.
 Instead input points locations can be selected and a predicted
values can be assigned to other locations.
 Input points can be either randomly or regularly spaced points
containing height, concentration or magnitude measurements.
ELEMENTS OF SPATIAL INTERPOLATION 17489318

4. Tobler’s law of Geography
Statement: Observations or
points which are close together
in space are more likely to have
similar values than the points
which are far apart.
ELEMENTS OF SPATIAL INTERPOLATION 17489318

5. A.INTERPOLATION
B.EXRAPOLATION
ELEMENTS OF SPATIAL INTERPOLATION 17489318

6.  Interpolation predicts values for a cell in a raster from a
limited number of samples data points.
 It can be used to predict unknown values for any
geographic point data , such as elevation , rainfall ,
chemical concentration etc.
 The interpolation cannot be done for : cyclic data,
counts and amounts, nominal data.
 One must have interval or ratio data for interpolation.
ELEMENTS OF SPATIAL INTERPOLATION 17489318

7. ELEMENTS OF SPATIAL INTERPOLATION 17489318

8. Spatial interpolation may be used in GIS:
 To calculate some property of the surface at a given
point.
 To provide contour for displaying data graphically.
 Frequently used in spatial decision making process
like terrain analysis , hydrology , mineral
prospecting etc
ELEMENTS OF SPATIAL INTERPOLATION 17489318

9. A classification of interpolation
methods:
 Global versus Local
 Exact versus Approximate
 Stochastic versus Deterministic
 Abrupt versus Smooth
ELEMENTS OF SPATIAL INTERPOLATION 17489318