Functions from Tools button panel, work differently. Once selected, they remain active and always follow the current data window until one switches to another tool. In other words one can switch data windows freely while using a tool and it always shows information from or operates on the current data. Tools also differ by working with selections, e.g. points, lines or rectangles, on data windows. Nevertheless functionally they perform similar tasks as functions – value reading, leveling, statistics, correction, etc.

menu and button panel either execute immediately or after asking for parameters and settings in a dialog box. Tools, accessible fromTools can be launched only from Tools button panel located in the main window. Gwyddion includes these tools:

- Read Value
Reads values at the position of mouse click.

- Distance
Measures distances – similarly to Read value this tool enables user to measure horizontal, vertical and Euclidean distance and angle between points in the data field. In addition it displays the difference of data values between points.

- Profiles Along Axes
Extracts horizontal and/or vertical scan line profiles from the image and puts them to separate graphs. These graphs can be further processed with commands from the

menu.- Profile
Extracts profiles along arbitrary lines from the image and puts them to separate graphs. These graphs can be further processed with commands from the

menu.- Radial Profiles
Extracts radial (angularly averaged) profiles from the image and puts them to separate graphs. These graphs can be further processed with commands from the

menu.- Spectro
Views and extracts single point spectroscopy data.

- Statistical Quantities
Computes basic statistical quantities (RMS, Ra, minimum, maximum, projected and surface area, etc.) from a selection of full data field. It can also calculate them only on the masked area, or even combine these two types of selection of area of interest.

- Statistical Functions
Computes basic statistical functions (distribution of heights or slopes, autocorrelation function, power spectrum density function, etc.) from a selection of full data field.

- Row/Column Statistics
Somewhat complementary to 1D statistical functions, this tool plots characteristics such as mean, median or surface length for each row (column).

- Correlation Length
Quick estimation of autocorrelation length T from scan lines using several common methods.

- Roughness
Evaluates standardized one-dimensional roughness parameters.

- Three Point Level
Levels data by plane obtained by clicking on three points within data window. The three values can be averaged over a small area around the selected point.

- Path Level
Row leveling tool equalizing the height along a set of arbitrary straight lines.

- Crop
Cuts part of the data.

- Mask Editor
Manual editing of masks: creation, exclusion, intersection, inversion, growing and shrinking, …

- Grain Measurement
Measures individual grain parameters.

- Grain Remover
Removes continuous parts of the mask by clicking on mask point and/or interpolates (removes) data under a continuous part of mask.

- Spot Remover
Manually removes spots. Select a point on a data window, mark an area to interpolate on the zoomed view and remove the defect using chosen interpolation method.

- Color Range
Stretches color range or changes false color mapping type. It enables the user to change the false color representation range (by default from data minimum to data maximum).

- Filter
Basic filters – mean, median, conservative denoise, minimum, maximum and similar simple filters to reduce noise in the data.

- Selection Manager
Displays selections for an image channel and copies them to other images or files.

Tool dialogs can be closed (or more precisely hidden, as the current tool
is still active even if its dialog is not visible), beside activating the
**Esc**
or clicking the tool's button in the toolbox again.