# Heatmap
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This documentation topic is designed for Grafana workspaces that support **Grafana version 8.x**.
For Grafana workspaces that support Grafana version 12.x, see [Working in Grafana version 12](using-grafana-v12.md).
For Grafana workspaces that support Grafana version 10.x, see [Working in Grafana version 10](using-grafana-v10.md).
For Grafana workspaces that support Grafana version 9.x, see [Working in Grafana version 9](using-grafana-v9.md).
The heatmap panel visualization allows you to view histograms over time. For more information about histograms, see [Introduction to histograms and heatmaps](getting-started-grafanaui.md#introduction-to-histograms-and-heatmaps).
## Axes options
Use these settings to adjust how axes are displayed in your visualization.
### Y Axis
+ **Unit** – The display unit for the y-axis value
+ **Scale** – The scale to use for the y-axis value
+ **linear** – Linear scale
+ **log (base 2)** – Logarithmic scale with base 2
+ **log (base 10)** – Logarithmic scale with base 10
+ **log (base 32)** – Logarithmic scale with base 32
+ **log (base 1024)** – Logarithmic scale with base 1024
+ **Y-Min** – The minimum y value (default is auto)
+ **Y-Max** – The maximum y value (default is auto)
+ **Decimals** – Number of decimals to render y-axis values with (default is auto)
### Buckets
**Note**
If the data format is **Time series buckets**, this section is not be available.
+ **Y Axis Buckets** – The number of buckets that the y-axis will be split into.
+ **Size** – The size of each y-axis bucket (visible only if **Scale** is *linear*). This option has priority over **Y Axis Buckets**.
+ **Split Factor** – (Only visible if **Scale** is *log (base 2)* or greater). By default, Amazon Managed Grafana splits y values by log base. With this option, you can split each default bucket into the specified number of buckets.
+ **X Axis Buckets** – The number of buckets that the x-axis will be split into.
+ **Size** – The size of each x-axis bucket. Number or time interval (10s, 5m, 1h, etc). Supported intervals: ms, s, m, h, d, w, M, y. This option has priority over **X Axis Buckets**.
#### Bucket bound
When Data format is Time series buckets, the data source returns series with names representing bucket bound. But depending on the data source, a bound can be upper or lower. You can use this option to adjust a bound type. If **Auto** is set, a bound option is chosen based on panels’ data source type.
#### Bucket size
The Bucket count and size options are used by Amazon Managed Grafana to calculate how big each cell in the heatmap is. You can define the bucket size either by count (the first input box) or by specifying a size interval. For the y-axis, the size interval is just a value. For the X-bucket, you can specify a time interval in the **Size** input. For example, you can set the time range to `1h`. This will make the cells 1h wide on the x-axis.
#### Data format
Choose an option in the **Format** list.
+ **Time series** – Amazon Managed Grafana does the bucketing by going through all time series values. The bucket sizes and intervals are set in the **Buckets** options.
+ **Time series buckets** – Each time series already represents a y-axis bucket. The time series name (alias) must be a numeric value representing the upper or lower interval for the bucket. The Grafana workspace does no bucketing, so the bucket size options are hidden.
## Display options
Use these settings to refine your visualization.
### Colors
The color spectrum controls the mapping between value count (in each bucket) and the color assigned to each bucket. The color on the far-left side of the spectrum represents the minimum count, and the color on the far-right side represents the maximum count. Some color schemes are automatically inverted when using the light theme.
You can also change the color mode to **Opacity**. In this case, the color will not change, but the amount of opacity will change with the bucket count.
+ **Mode**
+ **Opacity** – Bucket value represented by cell opacity. An opaque cell means the maximum value.
+ **Color** – Cell base color.
+ **Scale** – Scale for mapping bucket values to the opacity.
+ **linear** – Linear scale. Bucket value maps linearly to the opacity.
+ **sqrt** – Power scale. Cell opacity calculated as `value ^ k`, where `k` is a configured **Exponent** value. If the exponent is less than `1`, you will get a logarithmic scale. If the exponent is greater than `1`, you will get an exponential scale. In the case of `1`, the scale will be the same as linear.
+ **Exponent** – value of the exponent, greater than `0`.
+ **spectrum** – Bucket value represented by cell color.
+ **Scheme** – If the mode is **spectrum**, select a color scheme.
### Color scale
By default, Amazon Managed Grafana calculates cell colors based on minimum and maximum buckets values. With **Min** and **Max**, you can overwrite those values. Think of a bucket value as a z-axis and Min and Max as Z-Min and Z-Max respectively.
+ **Min** – Minimum value used for cell color calculation. If the bucket value is less than Min, it is mapped to the minimum color. The default is `series min value`.
+ **Max** – Maximum value used for cell color calculation. If the bucket value is greater than Max, it is mapped to the maximum color. The default is `series max value`.
### Legend
Choose whether to display the heatmap legend on the visualization or not.
### Buckets
+ **Hide zero** – Do not draw cells that have zero values.
+ **Space** – Set the space between cells in pixels. Default is 1 pixel.
+ **Round** – Set the cell roundness in pixels. Default is 0.
### Tooltip
+ **Show tooltip** – Show the heatmap tooltip.
+ **Histogram** – Show the y-axis histogram on the tooltip. The histogram represents distribution of the bucket values for the specific timestamp.
+ **Decimals** – Set the number of decimals to render bucket value with (default is auto).