**Table of Contents**

- Basic Operations
- Interpolation
- Data Leveling and Background Subtraction
- Masks
- Filters
- Presentations
- Data Edit and Correction
- Extended Data Edit
- Statistical Analysis
- One-Dimensional Roughness Parameters
- Grain Analysis
- Fourier Transform
- Wavelet Transform
- Fractal Analysis
- Tip Convolution Artefacts
- Multiple Data
- Graph Processing
- Volume Data Processing
- XYZ Data Processing
- Synthetic Surfaces
- Calibration and uncertainties
- Python Scripting

The number and breadth of data manipulation and analysis functions is one of the Gwyddion main strengths. The description of their principles and applications is the purpose of this chapter, with focus on the explanation of how they work and what they calculate or perform. Elements of their user interface are also occasionaly described where it seems useful, nevertheless, it is assumed the reader is familiar with the basic organization of data and controls in Gwyddion, as described in the previous chapter.