# Charting Overview

With the release of 1.3.0, charting has been completely revised. The previous version of charting is still available by selecting the Chart Old in Toolbar->View. Any scenes created with the older version of charting should display correctly in Chart Old. In addition, wb_view will attempt to convert old versions of charting to the new charting functionality.
Charting has expanded to include the display of histograms in addition to the pre-existing support for matrices and line-series data. An important feature of Charting is the simultaneous display of multiple charts for the selected chart type. In the Toolbar, the Chart Layers tab provides the selection of charts, as layers, similar to Layers used in the Overlays for surfaces and volumes.

## Histogram Charts

Histogram charts are available for any data file that contain one or more maps of scalar data and this includes many CIFTI file types, GIFTI metric files, and volume files. A histogram shows the distribution of data within a single map with an option to average the data from all maps. This map contain the same data that is mapped to brainordinates in surface and volume views. To view a histogram chart, change Toolbar->View mode to Chart and select Histogram in Toolbar->Chart Type. In Toolbox->Chart Layers, enable an overlay using an On checkbox and then choose a file and map for display as a histogram. Multiple histograms can be displayed using multiple layers. When displaying more than one histogram, one may want to change the histogram chart from Bars to Envelope by clicking the Layer's wrench button, selecting the Palette tab, and selecting the appropriate check boxes in the Histogram section. There are a variety of additional options for controlling the display of histograms.

## Line-Series Charts

Line-Series charts are available for most data files that contain multiple maps of scalar data. A line-series chart shows one data element from each map for a selected brainordinate (surface vertex or volume voxel). To display line-series charts from a data-file, one must enable the layer by checking the On checkbox and enable loading of line charts from the data-file by checking the Load checkbox. Note that the Load checkbox is a property of the file so if the same file is in more than one layer, the Load checkbox will maintain the same checked status in these layers. Once loading is enabled for a file, one must identify brainordinates by clicking the mouse on a surface vertex or a volume voxel. Doing so will load the data for the selected brainordinate and display the data as a line-chart. A history of line-charts loaded from a data file is available on in the Lines section of the Overlay and Map Settings dialog (click the Wrench button in the row containing the layer). One sets the number of chart lines displayed along with editing properties that include the color and thickness of the chart lines.

## Matrix Charts

Matrix charts are available for a limited number of files that contain parcellated connectivity. By default the full matrix is displayed. If the matrix is square (number of rows in the data file matches the number of columns) a button in the Layer controls the display of the matrix as the full matrix or the lower or upper quadrant. The palette mapping for coloring the matrix is identical to that used for display of the file's data in surface and volume overlays.