# GR Plot Overview

## Introduction

This program allows to create plots from the command line while using simple key-value pairs as arguments. The latter are converted into GRM containers which will then be used to plot the data. Alternatively a sender receiver mechanic can be used. For that start the grplot with the parameter `--listen`. The executable will now display the elements the sender sends to it.

## Command line arguments

The following parameters are key-value pairs which can be used for every plot type.

- `file`: contains the data which should be displayed. If no file is referred this results in an error message. If this parameter is the first argument the `file` keyword may be omitted. More information about these files can be found under the subchapter `Data file`. A hyphen '-' in place of a file path normally means "read from standard input". Since 'grplot' does not read from standard input by default, use '-' to redirect the input. This way 'grplot' can be used in a pipe.
- `kind`: defines the plot type that should be displayed. Possible options are: `barplot`, `contour`, `contourf`, `heatmap`, `hexbin`, `histogram`, `imshow`, `isosurface`, `line`, `marginal_heatmap`, `polar_heatmap`, `polar_histogram`, `polar_line`, `polar_scatter`, `pie`, `line3`, `scale`, `scatter`, `scatter3`, `shade`, `surface`, `stairs`, `stem`, `tricontour`, `trisurface`, `quiver`, `volume`, `wireframe`. The default plot type is `line`.

  To get extra information about a specific plot type use:

    ```shell
    --help plot_type
    ```

  Alternatively `-h` can be used instead of `--help`.

   The initial size of the window can be changed with following command at the beginning of the commandline arguments:

   ```shell
   --size width,height
   ```

There are more parameters that can be used for all two-dimensional data sets:

- `keep_aspect_ratio` or `aspect`: defines whether the aspect ratio of the initial picture is kept or not. Possible values for this parameter are 0 or 1.
- `only_quadratic_aspect_ratio`: defines whether the aspect ratio of quadratic data (x, y) is forced to be quadratic and kept this way or not. Notice this parameter will not work if the `keep_aspect_ratio` parameter has the value of 0. Possible values for this parameter are 0 or 1.
- `orientation`: This parameter defines the orientation of the displayed series. They can either be drawn `horizontal` or `vertical` while the default is `horizontal`.

For plots where multiple columns are read there is also a parameter that allows to select columns.

- `columns`: define the columns of the file which should be respected in the plot. The default is all columns. If all columns from x to y should be drawn use `x:y`. The `y` is necessary even if all lines from `x` to the end should be drawn. To select more than 1 specific column use the `,` without whitespace as separator.

For one-dimensional data sets there are also options to define if inside the data-file there are not just y- and maybe error-values included. These parameters are similar to the previous `column` parameter and can also be used in combination with it.

- `x_columns`: define the columns of the file which should represent the x-data. This is useful if multiple lines are included inside the plot where their y-values are not always on the same x-points. Another use case would be non-linear x-values which can not automatically generated by 'GR Plot'.
- `y_columns`: define the columns of the file which should represent the y-data. This parameter is only useful if either `x_columns` or `error_columns` is also used. Any column not included by those two is interpreted as y-values.
- `error_columns`: define the columns of the file which should represent the error-data. Depending on the status of the flag parameter `equal_up_and_down_error` this parameter must include either one or two columns for each y-column which should have error bars later. If this parameter is used and includes enough columns it is not needed to set `error` to enable the error bars. It can still be set to edit the resulting error bars.
- `xye_file`: defines a special case of the data-file. In this case the first column represents the x-, the second the y- and the third and maybe fourth column the error-values. The parameter can only have the values 0 and 1. If this parameter has the value 1 it is not needed to set `error` to enable the error bars. It can still be set to edit the resulting error bars.

There are more key-value parameters. These parameters only effect specific plot types. For example `bar_width` only makes sense, if bars are drawn. All possible parameters are:

`accelerate`, `algorithm`, `bar_color`, `bar_width`, `bin_counts`, `bin_edges`, `bottom`, `c`, `clip_negative`, `colormap`, `draw_edges`, `edge_color`, `edge_width`, `error_bar_style`, `error_columns`, `grplot`, `int_lim`, `isovalue`, `keep_radii_axes`, `kind`, `left`, `levels`, `line_spec`, `major_h`, `marginal_heatmap_kind`, `marker_type`, `num_bins`, `normalization`, `orientation`, `phi_flip`, `right`, `rotation`, `scatter_z`, `stairs`, `step_where`, `style`, `tilt`, `top`, `transformation`, `twin_x`, `twin_y`, `x_bins`, `x_colormap`, `x_columns` `x_flip`, `y_bins`, `y_colormap`, `y_columns`, `y_flip`, `y_labels`

All parameters are separated by a blank. Some parameters are more complex than others. These parameters represent a container inside GRM.

The valid container parameters are `error`, `ind_bar_color`, `ind_edge_color`, `ind_edge_width`.

Each parameter container can contain one or more of the following parameters:

1. `downwards_cap_color`: only available for `error`
2. `error_bar_color`: only available for `error`
3. `indices`: only available for `ind_bar_color`, `ind_edge_color`, `ind_edge_width`
4. `rgb`: only available for `ind_bar_color`, `ind_edge_color`
5. `upwards_cap_color`: only available for `error`
6. `width`: only available for `ind_edge_width`

Container parameters follow a different syntax than normal parameters. The parameters inside the container are enclosed by `{` `}`. If more than one parameter is given to the container each of the key-value pairs is enclosed by `{` `}` while the parameters are seperated by `,` without whitespace characters.

An example for some parameters on the command line:

```shell
file:covid19.csv kind:line columns:1:3,5
```

An example for using the stdin instead of the `file` keyword:

```shell
cat <data-file> | grplot -
```

This is an advanced example for a command line, where container parameters are set:

```shell
../../../../lib/grm/grplot/data/test.dat kind:barplot ind_edge_width:2,{{indices:2},{width:5.0},{indices:1},{width:8.0}} error:{error_bar_color:4}
```

If wanted the plot can be exported as a `pdf`, `png`, `jpeg` or `svg` file using the interactive menu. Alternatively these files can directly be created from console line if the environment variable `GKS_WSTYPE` is set.

## Test

The plots created from 'grplot' support in most cases interactions. These interactions can be used manually or via test cases. Further on these test cases allow to automatically test all the functionalities of 'grplot'. The biggest use case for these test cases is to verify if any made change inflicts any existing interaction.

To start 'grplot' with a test case you have to run:

```shell
grplot --test <command-file> <data-file> <parameter>
```

## Multiple plots

'grplot' also supports figures with multiple plots by using the --plot command line option. After this keyword the data-file must be named followed by the specific plot parameters if they should be applied to that plot. It's also possible to use interactions in each subplot.

To create multiple plots in one figure with 'grplot' use:

```shell
grplot --plot <data-file-1> <parameter-file-1> --plot <data-file-2> <parameter-file-2> ...
```

## Data file

These files contain the data that should be plotted. Besides the data these files can include parameters which modify the plot. Important to know is that the parameters which can stand in these files doesn't belong to a specific plot. They are atleast valid for all 2D or 3D plots for example. The first lines of teh datafile define parameters just like the `title` and have the following pattern:

```text
# key : value
```

Valid keys are:

1. `title`: sets the title of the plot
2. `x_label`, `y_label`, `z_label`: set the label for the respective axis
3. `resample_method`: defines how the data is resampled if needed
4. `location`: defines where the legend should be drawn
5. `x_log`, `y_log`, `z_log`: defines whether the respective axis is plotted logarithmic. These options only work if the data respects the definition of the logarithmic function.
6. `x_grid`, `y_grid`, `z_grid`: defines the grid for the respective axis
7. `phi_lim`, `r_lim`: defines which part of the specific polar axis should be displayed
8. `x_lim`, `y_lim`, `z_lim`: defines which part of the respective axis should be displayed
9. `x_range`, `y_range`, `z_range`: defines the range of the values on the respective axis

Values are seperated through commas (`,`), e.g. `3, 5`.

The next line after the header may contain the column labels. If the data does not have a label a blank line can be used instead. Data items are separated with a tab character (`\t`). Depending on the plot type the data is interpreted differently. The following list shows how the data is treated for different plot types.

1. `contour`, `contourf`, `heatmap`, `imshow`, `marginal_heatmap`, `surface`, `wireframe`: The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`. If the x- or y-values are non-linear this can not be handled by the previous explained data-format. For that there is another format which allows to define the x-, y- and z-values. Each values will stand in a different column while the x- and y-values will loop so that all columns have the same amount of rows. The x-values has to change first. To use this option the parameter flag `xyz_file` with the value of `1` can be used.
2. `line`, `scatter`: One or more columns are expected here. Each column will be displayed in a single plot. The values inside the columns gets therefore interpreted as y-values. In combination with the `error` parameter every 2nd (and 3rd) column gets interpreted as error-values. More information are found by the `error` parameter itself. There is also another option which allows the user to define which columns include the x-, y- and error-values. For this the parameters `x_columns`, `y_columns` and `error_columns` can be used. 
3. `isosurface`, `volume`: The expected data are multiple matrices. Each matrix represents a slice inside the volume.
4. `line3`, `scatter`, `scatter3`, `tricontour`, `trisurface`: Three columns with data are expected, representing the x-, y- and z-data.
5. `barplot`, `histogram`, `stem`, `stairs`: One or more columns are expected. Each column will be displayed in a single plot. The values inside the columns gets therefore interpreted as y-values. In combination with the `error` parameter the 2nd (and 3rd) column gets interpreted as error-values. More information are found by the `error` parameter itself. There is also another option which allows the user to define which column include the x-, y- and error-values. For this the parameters `x_columns`, `y_columns` and `error_columns` can be used.
6. `pie`: The expected data are 1-4 lines. The first line represents the data which should be displayed. The next 3 rows are used to set the RGB of the pie charts. Each row stands for one RGB element.
7. `polar_histogram`: One column is expected which represents the values.
8. `polar_line`, `polar_scatter`: The expected data are pairs of two columns containing the angles and values.
9. `polar_heatmap`: The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in theta- and phi-direction. If not given, theta will be in the range of 0.0 and 3.0 while phi will be in range of 0.0 and 360.0. Both parameters can be changed with `x_range` for theta and `y_range` for phi.
10. `quiver`: The expected data are two matrices. The first matrix contains the information about the x-directions and the second matrix the information about the y-directions.
11. `hexbin`, `shade`: The expected data are two columns, representing the x- and y-data.

A plot type that expect the same data shape as other plot types can be converted using an interactive menu. The interaction also yields extra information about the plot, if the mouse is being hovered over them.

If some data from the data file should be plotted to a different axis as the rest of the data, this can be achieved with the following parameters: `bottom`, `left`, `right`, `top`, `twin_x`, `twin_y`. Each of these parameters defines an axis at the named position. The values of these keys specify a single or more series which will be plotted to that axis from key.

## Editor

The editor can be enabled by setting the environment variable `GRDISPLAY` to the value of `edit`. After that the editor can be activated and deactivated via the interactive menubar. The editor allows to modify the displayed plot in parts.

## Advanced information for each plot type

### BARPLOT

This plot type converts the data into a bar plot. A bar plot itself is used to display the relationship between a numeric and a categorical variable. The resulting bars represent the frequency or quantity of different categories of the data.

The expected data is one column representing the y-data.

Possible parameters for the bar plot are:

1. `bar_color`: This parameter defines the color of all bars inside the plot except of those which are referred with `ind_bar_color`. The value of this parameter can either be an integer which represents a color index or three doubles which represent the RGB value of the color. If the parameter isn't set the bars will have the color with index 989 (dark blue).
2. `bar_width`: This parameter defines the width of all bars inside the plot. Depending on the specified width the bars may overlap. The value of this parameter is a double number where its default is 0.8.
3. `edge_color`: This parameter defines the color of all edges inside the plot except of those which are referred with `ind_edge_color`. The value of this parameter can either be an integer which represents a color index or three doubles which represents the RGB value of the color. If the parameter isn't set the edges will have the color with index 1 (black).
4. `edge_width`: This parameter defines the width of all edges inside the plot except those which are referred with `ind_edge_width`. The value of this parameter is a double number where its default is 1.0.
5. `error`: With this parameter the relative error of each bar can be displayed. The values for this parameter are key-value pairs with the following keys:
    - `error_bar_color`: Defines the color of the error bars as an integer. If no color is given an error is raised.
    - `downwards_cap_color`: Defines the downwards cap color of the error bars as an integer.
    - `upwards_cap_color`: Defines the upwards cap color of the error bars as an integer.

   Note: If the error of the bars is to be displayed, the last two columns of the data are used for the error. If the up and down error are equal use `equal_up_and_down_error` with a value of `1`. In that case only one column is expected for the error data instead of the two. This parameter flag also does not need the `error` parameter to be set. Like by the `error` parameter some of the columns inside the data will get interpreted as error-values. The syntax of this parameter is:

   `error:{{error_bar_color:`color_index`},{downwards_cap_color:`color_index`},{upwards_cap_color:`color_index`}}`

6. `error_bar_style`: Defines how the error-bars are displayed. As single error-lines(0) or as an error-area(1).
7. `ind_bar_color`: With this parameter the color of specific bars can be changed. The value of this parameter are key-value pairs with the following keys:
    - `indices`: The index number of the bar, which color should be changed.
    - `rgb`: The new color for the specified bar. The value has to be three doubles or integer which represents the RGB value.

   The syntax of this parameter is:

   `ind_bar_color:`number_of_bars`,{{indices:`first_bar_index`},{rgb:`r1,g1,b1`}`,...`}`
8. `ind_edge_color`: With this parameter the color of specific edges can be changed. The value of this parameter are key-value pairs with the following keys:
    - `indices`: The index number of the edge, which color should be changed.
    - `rgb`: The new color for the specified edge. The value has to be three doubles or integer which represents the RGB value.

   The syntax of this parameter is:

   `ind_edge_color:`number_of_edges`,{{indices:`first_edge_index`},{rgb:`r1,g1,b1`}`,...`}`
9. `ind_edge_width`: With this parameter the width of specific edges can be changed. The value of this parameter are key-value pairs with the following keys:
    - `indices`: The index number of the edge, which width should be changed.
    - `width`: The new width for the specified edge. The value of this parameter has to be an integer or double.

   The syntax of this parameter is:

   `ind_edge_width:`number_of_edges`,{{indices:`first_edge_index`},{width:`first_edge_width`}`,...`}`
10. `style`: This parameter defines how the data inside the bar plot is displayed. There are three options:
    - `default`: All values are displayed with a separate bar.
    - `stacked`: The values are displayed with bars which are stacked over each other.
    - `lined`: The values are displayed with smaller bars next to each other.
11. `y_labels`: This parameter allows the user to set labels to specific bars, which can for example display the value of the bar. The syntax of this parameter is `y_labels:{`label1`,`label2`,`...`}`.

### CONTOUR

This plot type converts the data into a contour plot. A contour plot displays the three-dimensional data over a rectangular mesh. Depending on the specified number of `levels` contour lines are displayed which represent the different height values.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the contour plot are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `levels`: This parameter defines how many contour lines should be drawn. The default is 20.
3. `major_h`: This parameter defines if contour labels should be drawn or not. Any number greater 0 defines which lines will be labeled. An offset of 1000 to this parameter will color the lines aswell.
4. `x_flip`: This parameter defines whether the x-axis is flipped or not.
5. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### CONTOURF

This plot type converts the data into a contourf plot. A contourf plot displays the three-dimensional data over a rectangular mesh. Depending on the specified number of `levels` contour lines are displayed which represent the different height values. The space between the contour lines is filled with a color respecting the specified colormap.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the contourf plot are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `levels`: This parameter defines how many contour lines should be drawn. The default is 20.
3. `major_h`: This parameter defines if contour labels should be drawn or not. Any number greater 0 defines which lines will be labeled. An offset of 1000 to this parameter will color the lines aswell.
4. `scale`: This parameter sets the type of transformation to be used (refer to [gr_setscale](https://gr-framework.org/c-gr.html?highlight=gr_setscale#_CPPv411gr_setscalei)).
5. `x_flip`: This parameter defines whether the x-axis is flipped or not.
6. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### HEATMAP

This plot type converts the data into a heatmap. A heatmap uses the current colormap to display the data. Each data point is represented with a colored square which size depends on the amount of data.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the heatmap are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `levels`: This parameter defines how many contour lines should be drawn. The default is 20.
3. `x_flip`: This parameter defines whether the x-axis is flipped or not.

### HEXBIN

This plot type converts the data into a hexbin. A hexbin uses hexagonal binning and the current colormap to display the data.

Possible parameters for the hexbin are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `num_bins`: This parameter defines the number of bins which represent a hexagonal cell in the plot. The default is 40.
3. `levels`: This parameter defines how many contour lines should be drawn. The default is 20.
4. `x_flip`: This parameter defines whether the x-axis is flipped or not.

### HISTOGRAM

This plot type converts the data into a histogram. A histogram is an approximate representation of the distribution of numerical data. Two columns are expected containing the x- and the y-data.

Possible parameters for the histogram are:

1. `bar_color`: This parameter defines the color of all bars inside the plot. The value of this parameter can either be an integer which represents a color index or three doubles which represents the RGB value of the color. If the parameter is omitted color 989 (dark blue) will be used.
2. `bins`: This parameter defines the number of bins which should be used to represent the distribution of the data. The default value is 3.3 * log10(number of points) + 0.5) + 1.
3. `edge_color`: This parameter defines the color of all edges inside the plot. The value of this parameter can either be an integer which represents a color index or three doubles which represents the RGB value of the color. If the parameter is omitted color 1 (black) will be used.
4. `error`: With this parameter the relative error of each bar can be displayed. The parameters are key-value pairs with the following keys:
    - `error_bar_color`: Defines the color of the error bars. If no color is given an error is raised.
    - `downwards_cap_color`: Defines the downwards cap color of the error bars.
    - `upwards_cap_color`: Defines the upwards cap color of the error bars.

   Note: If the error of the bars is to be displayed, the last two columns of the data are used for the error. If the up and down error are equal use `equal_up_and_down_error` with a value of `1`. In that case only one column is expected for the error data instead of the two. This parameter flag also does not need the `error` parameter to be set. Like by the `error` parameter some of the columns inside the data will get interpreted as error-values. The syntax of this parameter is:

   `error:{{error_bar_color:`color_index`},{downwards_cap_color:`color_index`},{upwards_cap_color:`color_index`}}`

5. `error_bar_style`: Defines how the error-bars are displayed. As single error-lines(0) or as an error-area(1).

### IMSHOW

This plot type converts the data into an imshow plot. The data is displayed as a colored image where each data point is represented as a colored rectangle inside the image.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the imshow plot are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `grplot`: This parameter is there for the consistency between the plot types `contour`, `contourf`, `heatmap`, `imshow`, `marginal_heatmap`, `surface`, `wireframe`. If set the data is displayed in the same order by all of these types where in general the imshow plot would be flipped. The value can be either 0 or 1 where the value if not otherwise set is always 1.
3. `x_flip`: This parameter defines whether the x-axis is flipped or not.
4. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### ISOSURFACE

This plot type converts the data into an isosurface. An isosurface is a three-dimensional analog of a contour- or isoline.

The expected data are multiple matrices. Each matrix is similar to a slice inside the volume.

Possible parameters for the isosurface are:

1. `isovalue`: Values greater than the isovalue will be seen as outside the isosurface, while values less than the isovalue will be seen as inside the isosurface. The value has to an integer or double where the default is 0.5.
2. `rotation`: This parameter defines the rotation of the displayed data in degrees. The value of this parameter has to be an integer or double. The default is no rotation.
3. `tilt`: This parameter defines the tilt of the camera in degrees. The value of this parameter has to be an integer or double. The default is no tilt.

### LINE

This plot type converts the data into a line plot. A line plot is a simple plot where the data points are connected by a polyline.

The expected data are columns. Each column will be interpreted as a single line. Multiple columns leads to multiple displayed lines. The values inside the columns gets therefore interpreted as y-values.

Possible parameters for the line plot are:

1. `error`: With this parameter the relative error of each line can be displayed. The value of this parameter are key-value pairs with the following keys:
    - `error_bar_color`: Defines the color of the error bars. The value of this parameter has to be an integer. If no color is given this leads to an error.
    - `downwards_cap_color`: Defines the downwards cap color of the error bars. The value of this parameter has to be an integer.
    - `upwards_cap_color`: Defines the upwards cap color of the error bars. The value of this parameter has to be an integer.

      Note: If the error of the points is to be displayed, the last two columns of each pair of three columns from the data are used for the error. This means for a dataset with eight columns that columns 2, 3, 5, 6 are used for the error bars. If the up and down error are equal use `equal_up_and_down_error` with a value of `1`. In that case only one column is expected for the error data instead of the two. This parameter flag also does not need the `error` parameter to be set. Like by the `error` parameter some of the columns inside the data will get interpreted as error-values. The syntax of this parameter is:

   `error:{{error_bar_color:`color_index`},{downwards_cap_color:`color_index`},{upwards_cap_color:`color_index`}}`

2. `error_bar_style`: Defines how the error-bars are displayed. As single error-lines(0) or as an error-area(1).
3. `int_limits_high`: This parameter defines the upper limits of all integrals.
   
    The syntax for this parameter is:

   `int_limits_high:`number_of_elements`,`elem_1`,`elem_2`,`...

4. `int_limits_low`: This parameter defines the lower limits of all integrals.

    The syntax for this parameter is:

   `int_limits_low:`number_of_elements`,`elem_1`,`elem_2`,`...

### MARGINAL_HEATMAP

This plot type converts the data into a marginal heatmap. A marginal heatmap is a combination of a heatmap and either stairs plots or histograms. With those extra plots some parts of the heatmap data are displayed in vertical and horizontal direction at the margins of the heatmap.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the marginal heatmap are:

1. `algorithm`: This parameter defines whether the data is summed up or if the maximum to be used for the side plots. Possible values are `max` and `sum` where the default is `sum`.
2. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
3. `marginal_heatmap_kind` or `h_kind`: This parameter defines what part of the data is displayed inside the side plots. Possible options are:
    - `all`: If the kind is set to all, the side plots respect the complete data of the heatmap. This is the default case.
    - `line`: If the kind is set to line, the side plots respect only a specific row/column of the data.
4. `x_flip`: This parameter defines whether the x-axis is flipped or not.
5. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### POLAR_HEATMAP

This plot type converts the data into a polar heatmap. A polar heatmap is a heatmap in polar coordinates.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in phi- and theta-direction. If not given, theta will be in the range of 0.0 and 3.0 while phi will be in range of 0.0 and 360.0. Both parameters can be changed with `x_range` for phi and `y_range` for theta.

Possible parameters for the polar heatmap are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).

### POLAR_HISTOGRAM

This plot type converts the data into a polar histogram. A polar histogram corresponds to a histogram in polar coordinates.

The expected data is one column containing the values.

Possible parameters for the polar histogram are:

1. `bin_counts`: This parameter sets the amount of classes without binning.
2. `bin_edges`: This parameter sets the borders of the classes.
3. `bin_width`: This parameter sets the width of all the bins.
4. `draw_edges`: If a colormap is used this parameter decides whether the outer shape is drawn or not. The value can be either 0 or 1.
5. `keep_radii_axes`: This parameter only have an impact, if `y_lim` is set. In that case the ranges for the radii axes from `y_lim` get ignored while the polar histogram still gets affected by the `y_lim`.
6. `num_bins`: This parameter sets the number of classes which are respected during the binning.
7. `normalization`: This parameter sets the type of normalization for the polar histogram. The value can be `count`, `probability`, `countdensity`, `pdf`, `cumcount` or `cdf`.
8. `phi_flip`: This parameter decides whether the phi values are flipped or not. The value can be either 0 or 1.
9. `stairs`: If this parameter is set, only the outer shapes of the bins are drawn. The value can be either 0 or 1.
10. `x_colormap`: This parameter sets the colormap for the x-direction.
11. `x_flip`: This parameter defines whether the x-axis is flipped or not.
12. `y_colormap`: This parameter sets the colormap for the y-direction.
13. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### POLAR_LINE

This plot type converts the data into a polar plot/line-plot. A polar plot displays a polyline in polar coordinates, with theta indicating the angle in radians and rho indicating the radius value for each point.

The expected data are two columns containing the angles and values.

Possible parameters for the polar line plot are:

1. `clip_negative`: If this parameter is set, only positive radii are displayed, otherwise negative will be mirrored

### POLAR_SCATTER

This plot type converts the data into a polar scatter plot. A polar scatter displays each data point as a point inside the polar coordinate system, with theta indicating the angle in radians and rho indicating the radius value for each point.

The expected data are two columns containing the angles and values.

Possible parameters for the polar scatter plot are:

1. `clip_negative`: If this parameter is set, only positive radii are displayed, otherwise negative will be mirrored

### PIE

This plot type converts the data into a pie plot. A Pie Chart is a circular statistical plot that can display one series of data. The area of the chart is the total percentage of the given data. The area of slices of the pie represents the percentage of the parts of the data.

The expected data are 1-4 lines. The first line represents the data to be displayed. The next three rows are used to set the RGB values for the slices.

### LINE3

This plot type converts the data into a three-dimensional line plot. The data points inside the three-dimensional space are connected through polylines.

The expected data are three columns containing the x-, y- and z-data.

### SCATTER

This plot type converts the data into a scatter plot. A scatter plot displays each data point as a point inside the two-dimensional coordinate system.

The expected data are columns. Each column will be interpreted as a single plot. Multiple columns lead to multiple plots. The column values are interpreted as y-values. There is also a special case of the scatter plot where the size of the points can be given.

Possible parameters for the scatter plot are:

1. `error`: With this parameter the relative error of each line can be displayed. The value of this parameter are key-value pairs with the following keys:
    - `error_bar_color`: Defines the color of the error bars. The value of this parameter has to be an integer. If no color is given this leads to an error.
    - `downwards_cap_color`: Defines the downwards cap color of the error bars. The value of this parameter has to be an integer.
    - `upwards_cap_color`: Defines the upwards cap color of the error bars. The value of this parameter has to be an integer.

   Note: If the error of the points is to be displayed, the last two columns of the data are used for the error. If the up and down error are equal use `equal_up_and_down_error` with a value of `1`. In that case only one column is expected for the error data instead of the two. This parameter flag also does not need the `error` parameter to be set. Like by the `error` parameter some of the columns inside the data will get interpreted as error-values. The syntax of this parameter is:

   `error:{{error_bar_color:`color_index`},{downwards_cap_color:`color_index`},{upwards_cap_color:`color_index`}}`

2. `error_bar_style`: Defines how the error-bars are displayed. As single error-lines(0) or as an error-area(1).
3. `marker_type`: This parameter defines the style of the visualized data points, where the effect belonging to the numbers is the same as for [gr_setmarkertype](https://gr-framework.org/c-gr.html?highlight=gr_setmarkertype#_CPPv416gr_setmarkertypei).

### SCATTER3

This plot type converts the data into a three-dimensional scatter plot. A three-dimensional scatter plot displays each data point as a point inside the three-dimensional coordinate system.

The expected data are three columns containing the x-, y- and z-data.

### SHADE

This plot type converts the data into a shade plot. With a shade plot a point or line based heatmap can be drawn from the data.

The expected data are two columns containing the x- and y-data.

Possible parameters for the shade plot are:

1. `transformation`: This parameter defines the transformation type used for color mapping. The value of this parameter has to be an integer where the default is 1. The effect belonging to the numbers is the same as for [gr_shadepoints](https://gr-framework.org/c-gr.html?highlight=gr_shadepoints#_CPPv414gr_shadepointsiPdPdiii).
2. `x_bins`: This parameter defines the bins in x-direction. The value of this parameter has to be an integer where the default is 100.
3. `y_bins` : This parameter defines the bins in y-direction. The value of this parameter has to be an integer where the default is 100.

### SURFACE

This plot type converts the data into a surface plot. A surface plot is to be compared with a visualization of a function of two variables inside the three-dimensional space.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.

Possible parameters for the surface plot are:

1. `accelerate`: This parameter defines whether the surface plot is calculated with the GR or the GR3 functionalities. The value of this parameter has to be 0 or 1 where in its default case the GR3 to be used.
2. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
3. `x_flip`: This parameter defines whether the x-axis is flipped or not.
4. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### STAIRS

This plot type converts the data into a stairs plot. A stairs plot is a piecewise constant function having only finitely many pieces.

The expected data is 1 column. This column represents the y-data.

Possible parameters for the stairs plot are:

1. `step_where`: This parameter defines the calculation of the steps. The possible values are `pre`, `post` and `mid` which is also the default case.

### STEM

This plot type converts the data into a stem plot. A stem plot draws lines perpendicular to a baseline at each location from the baseline to the data values.

The expected data is one column containing the y-data.

### TRICONTOUR

This plot type converts the data into a tricontour plot. A tricontour plot displays contour lines on an unstructured triangular grid.

The expected data are 3 columns. The first columns represents x-, the second y- and the last the z-data.

The possible parameters for the tricontour plot are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `levels`: This parameter determines the number and positions of the contour lines/regions. The default is 20.
3. `x_flip`: This parameter defines whether the x-axis is flipped or not.
4. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### TRISURFACE

This plot type converts the data into a trisurfaces. A trisurface is a type of surface plot, created by triangulation of compact surfaces of finite number of triangles which cover the whole surface in a manner that each and every point on the surface is in triangle.

The expected data are 3 columns. The first columns represents x-, the second y- and the last the z-data.

Possible parameters for the trisurface are:

1. `colormap` or `cmap`: This parameter defines the colormap to be used. The default is 44 (viridis).
2. `x_flip`: This parameter defines whether the x-axis is flipped or not.
3. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### QUIVER

This plot type converts the data into a quiver plot. A quiver plot is a type of 2D plot that shows vector lines as arrows.

The expected data are 2 matrices. The first matrix contains the information of the x-directions and the second matrix the information of the y-directions.

Possible parameters for the quiver plot are:

1. `x_flip`: This parameter defines whether the x-axis is flipped or not.
2. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### VOLUME

This plot type converts the data into a volume plot. A volume plot draws a three-dimensional data set using volume rendering. The volume data is reduced to a two-dimensional image using an emission or absorption model or by a maximum intensity projection. After the projection the current colormap is applied to the result.

The expected data are multiple matrices. Each matrix is similar to a slice inside the volume.

Possible parameters for the volume plot are:

1. `algorithm`: This parameter defines which model to be used for the reduction of the data. The possible values are `emission`, `absorption` and `mip` which is the same as `maximum`.
2. `x_flip`: This parameter defines whether the x-axis is flipped or not.
3. `y_flip`: This parameter defines whether the y-axis is flipped or not.

### WIREFRAME

This plot type converts the data into a wireframe plot. A wireframe plot takes a grid of values and projects it onto the specified three-dimensional surface. The surface itself has a grid structure.

The expected data is a matrix. Each element of the matrix is displayed according to its position inside the matrix. These elements are interpreted as values in x- and y-direction. With the parameter `use_bins:1` the first row and column of the data is interpreted as information about the `x_range` and `y_range`.
