Spatial interpolation is the process of estimating values in locations that do not have measured values based on known values at other locations. There are several key elements to spatial interpolation, including control points which are locations of known values, the number and distribution of control points, and the type of interpolation method used which can be global or local. Interpolation methods can also be categorized as exact or inexact, and deterministic or stochastic, with stochastic providing assessments of prediction errors. Kriging is a specific geostatistical interpolation method that can assess the quality of predictions and estimates prediction errors.

1. GEOGRAPHICAL
INFORMATION
SYSTEM
UNIT 6
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2. Spatial Interpolation
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3. What is interpolation
 Process of creating a surface based on
values at isolated sample points.
 We use mathematical estimation to “guess
at” what the values are “in between” those
points
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4. Elements of Spatial
Interpolation
 Control Points.
 Control Points are points with known values.
 The number and distribution of control points can
greatly influence the accuracy of spatial interpolation.
 Type of Spatial Interpolation.
 Global Interpolation:- It uses every known point
available to estimate an unknown value.
 Local Interpolation:- It uses a sample of known points
to estimate an unknown value.
 Spatial Interpolation can be grouped into Exact and Inexact
interpolation, Stochastic and Deterministic interpolation
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5.  Exact vs. Inexact
 Exact interpolation predicts a value at the point
location that is the same as its known value. In
other words, exact interpolation generates a
surface that passes through the control points. In
contrast,
 inexact interpolation or approximate interpolation
predicts a value at the point location that differs
from its known value.
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6.  Deterministic vs. Stochastic
 A deterministic interpolation method provides no
assessment of errors with predicted values.
 A stochastic interpolation method, on the other
hand, offers assessment of prediction errors
with estimated variances.
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7. WE-IT TUTORIALS (PH:8097071144/55)

8.  Kringing:
 Kringing is a geostatistical method for spatial
interpolation. Kringing differs from the
interpolation methods discussed so far because
kringing can assess the quality of prediction with
estimated prediction errors.
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9. END OF UNIT 6
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