Line charts

Line charts are one of the chart types available for viewing data in our system. This type of chart displays points along an x and y axis, with lines connecting points along the x axis.

The x-axis selects the values that will be displayed along the horizontal axis. An x-axis attribute in a line chart must be a sequential (i.e. a date) or numeric value.

Line charts must also have a numeric y-axis value. This could be the value of a numeric attribute, or the count of non-numeric records corresponding to a value. Counts can include all records or be filtered by an attribute. That is, all records not matching the filter will be left out of the display.

You can also choose to group x-axis values to simplify the number of values displayed. That is, records will be clumped together by value based on the degree of granularity chosen by the user.

Before value grouping

After value grouping

If you choose to group, you have additional options for displaying your values on the y-axis when you have a numerical display attribute. In that case, you must select between showing the minimum record value, maximum record value, sum of record values, average value, or simply a count of the matching records.

For non-numeric attributes, there is only an option to see a count.

Furthermore, on the y-axis you can filter by a selected factor. You can do this by selecting "where" instead of "of all records" from the menu next to the grouping selection. This will limit the data displayed to the criteria you add.

Users can filter by any kind of attribute. For example, for text, you can filter by exact matches or by records containing a string. Numbers can be filtered by records above, below, matching, or between a user specified amount.

You can also filter by date and filter by records before, after, matching, or between a certain date. The widget to do this is a calendar and can be moved forward or backward in time by the day, month, or year.

You can choose to show multiple series of data at once on the y-axis. Each will have its own coloration to distinguish it. Simply click the "+" button to add additional data, or the '-' button to remove a series.

Series of data can be different attributes, or the same attribute with different filtering, grouping, or calculation method (i.e. sum, count, min, max or average).

When different series are made up of different attributes, they will be displayed with their own y-axis label.

This can end up looking cluttered if you are looking at a lot of series together.

There are two ways to simplify this. The first is to move series to the right of the chart. You can do this by clicking on the swatch for a series and then selecting the "side of chart" as right.

Additionally, you can merge your axis into one and scale all values accordingly. You can do this by clicking the checkbox labeled "Merge Y Axes" just above your x-axis series list.

Line charts can also be turned into area charts by adding a fill color underneath the line.

Area charts can be stacked so that one can see the sums of several series together.

Or, alternatively, they can use a percentage with a stacked chart in order to see series compared to one another as part of a whole. You will have a lot of latitude with this feature to show attributes with differing scales, so keep that in mind when comparing series with vastly different measures.

You can also change the color, opacity, under line fill, size, and shape of points and lines by clicking on the swatch for a series and making your desired changes.

Series can be turned off and on by clicking the checkbox to the left of the series rule definintion.

Keep in mind that the number of points in a chart will affect the performance. You will get a warning at 1000 points and the system will not draw a chart with more than 10,000.

Like all other charts, line charts can be saved as a snapshot and viewed again later, or used to make new chart visualizations. Just click "save snapshot" at the top of the page.