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vector data analysis in GIS Surface Analysis – Interpolation – IDW

1. Surface Analysis 🗺️

  • This is when we try to understand and visualize how a value changes across a surface (like land).

  • The values might be temperature, rainfall, elevation, pollution levels, etc.

  • We often start with only some points where we know the value, but we want to guess the values everywhere in between.

2. Interpolation 📍➡️📍

  • Interpolation is a way of estimating unknown values between known points.

  • Imagine you know the temperature at a few weather stations, but you want to know the temperature everywhere in between.

  • GIS uses math to "fill in the blanks" between the points.

3. IDW (Inverse Distance Weighted) 🎯

  • One popular interpolation method.

  • The idea: Points that are closer to you have more influence than points farther away.

  • Example: If you're standing between two rain gauges, the closer one's reading will affect your estimated rainfall more than the farther one.

  • "Inverse Distance" means: The farther away, the less weight it gets.

  • Result: A smooth map showing predicted values across the whole area.

It's like colouring a map using the few measurements you have, with the rule that nearby measurements matter more than faraway ones.

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