# 1 Simple graphs

#### Overview

Simple graphs are provided for the visualization of data gathered by
items.

No configuration effort is required on the user part to view simple
graphs. They are freely made available by Zabbix.

Just go to *Monitoring → Latest data* and click on the Graph link for
the respective item and a graph will be displayed.

![](../../../../../assets/en/manual/config/simple_graph.png){width="600"}

#### Time period selector

Take note of the time period selector above the graph. It allows you to
select the desired time period easily.

The slider within the selector can be dragged back and forth, as well as
resized, effectively changing the time period displayed. Links on the
left hand side allow to choose some often-used predefined periods (above
the slider area) and move them back and forth in time (below the slider
area). The dates on the right hand side actually work as links, popping
up a calendar and allowing to set a specific start/end time.

The **fixed/dynamic** link in the lower right hand corner has the
following effects:

-   controls whether the time period is kept constant when you change
    the start/end time in the calendar popup.
-   when *fixed*, time moving controls (<< 1m 7d 1d 12h 1h 5m | 5m
    1h 12h 1d 7d 1m >>) will move the slider, while not changing
    its size, whereas when *dynamic*, the control used will enlarge the
    slider in the respective direction.
-   when *fixed*, pressing the larger **<** and **>** buttons will
    move the slider, while not changing its size, whereas when
    *dynamic*, **<** and **>** will enlarge the slider in the
    respective direction. The slider will move by the amount of its
    size, so, for example, if it is one month, it will move by a month;
    whereas the slider will enlarge by 1 day.

Another way of controlling the displayed time is to highlight an area in
the graph with the left mouse button. The graph will zoom into the
highlighted area once you release the left mouse button.

::: noteclassic
Simple graphs are provided for all numeric items. For
textual items, a link to History is available in *Monitoring → Latest
data*.
:::

#### Recent data vs longer periods

For very recent data a **single** line is drawn connecting each received
value. The single line is drawn as long as there is at least one
horizontal pixel available for one value.

For data that show a longer period **three lines** are drawn - a dark
green one shows the average, while a light pink and a light green line
shows the maximum and minimum values at that point in time. The space
between the highs and the lows is filled with yellow background.

Working time (working days) is displayed in graphs as a white
background, while non-working time is displayed in grey (with the
*Original blue* default frontend theme).

![](../../../../../assets/en/manual/config/graph_workingtime.png){width="550"}

Working time is always displayed in simple graphs, whereas displaying it
in [custom graphs](custom#configuring_custom_graphs) is a user
preference.

Working time is not displayed if the graph shows more than 3 months.

##### Generating from history/trends

Graphs can be drawn based on either item [history or
trends](/manual/config/items/history_and_trends).

A grey caption at the bottom right of a graph indicates where the data
come from.

::: noteimportant
Since Zabbix 3.4.3, this caption showing
history/trends as the source is vertical and displayed only for the
users who have frontend [debug mode](/manual/web_interface/debug_mode)
activated.
:::

Several factors influence whether history of trends is used:

-   longevity of item history. For example, item history can be kept for
    14 days. In that case, any data older than the fourteen days will be
    coming from trends.

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```
-   data congestion in the graph. If the amount of seconds to display in
    a horizontal graph pixel exceeds 3600/16, trend data are displayed
    (even if item history is still available for the same period).

```{=html}
<!-- -->
```
-   if trends are disabled, item history is used for graph building - if
    available for that period. This is supported starting with Zabbix
    2.2.1 (before, disabled trends would mean an empty graph for the
    period even if item history was available).

#### Absence of data

For items with a regular update interval, nothing is displayed in the
graph if item data are not collected.

However, for trapper items and items with a scheduled update interval
(and regular update interval set to 0), a straight line is drawn leading
up to the first collected value and from the last collected value to the
end of graph; the line is on the level of the first/last value
respectively.

#### Switching to raw values

A dropdown on the upper right allows to switch from the simple graph to
the *Values/500 latest values* listings. This can be useful for viewing
the numeric values making up the graph.

The values represented here are raw, i.e. no units or postprocessing of
values is used. Value mapping, however, is applied.

#### Known issues

See [known issues](/manual/installation/known_issues#graphs) for graphs.