What is interpolation?
It is a method to predict the values (values) of raster cells (pixels). This work is done by a limited number of sample points. The uses of this method in GIS work are many (especially in the fields of
agriculture and natural resources).
From this method to obtain height, rainfall, chemical concentration of substances and. is used
Example: Suppose you have a surface that has 20 scattered height points. Each of these points represents a certain height. By using mediation, you can know the height of your entire surface so that wherever you choose on this surface, it shows the height of that point.
Mediation methods:
To create raster surfaces from point data, there are several methods as follows.
IDW, natural neighbors, spline —— kriging and the most used of them
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inverse distance weighted or IDW
In this method, it is assumed that your sample points are affected by the location. In fact, sample points have a weight effect. In other words, pixels close to the sample points have more effect than pixels further away from these points
they take So, this method is suitable in situations where the weight of cells decreases with increasing distance from your sample points
Example: As a GIS expert, you want to analyze the purchasing power of a consumer from several supermarkets.
Certainly, the purchasing power of people whose residence is far from the supermarket is lower than the purchasing power of people
which are close to the supermarket. So you should use the IDW method to perform this analysis.
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Natural neighbors: This method is a weighted method like the IDW method, but with IDW in details
There are differences. This method is suitable when the distribution of sample points is irregular. This method has an advantage
It is that it does not need to specify specific parameters such as radius, number of neighbors or weight.
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spline: This interpolation method is the best method for surfaces whose changes are gradual: height, water depth, and pollution
. If you have a lot of changes in a small horizontal distance, spline is not a suitable method for interpolation because it shows your estimated values more than the actual value.
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Kriging: In this method, it is assumed that the distance and direction between the sample points affects the spatial correlation
This method has the best efficiency when there is distance correlation or directional skewness of the data
Be aware. This method is often used in petroleum and geology sciences.
Remember something well. If it is important to you how accurate the result of your cartoon is, be very careful in using this type of interpolation and don’t just use kriging like others. Because each uses
You can use these methods in 3D Analyst or Spatial Analysis in ArcGIS software.
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This post is written by Mb7395