# Raster layers

{% embed url="<https://www.youtube.com/watch?v=ZySJoTMYG_M>" %}

Raster data is often displayed as greyscale or color images. However, sometimes you want to style raster layers in different ways depending on the type of data.

## Choosing your map type

<figure><img src="/files/ikdiZMyAhUWKQTYohfjx" alt="" width="327"><figcaption></figcaption></figure>

### Image

The default style when you upload a raster data layer. Images will either be grayscale (for rasters with one or two bands) or colored (RGB) for rasters with three or more.

In an **`Image`** layer, the only styling property available is the opacity, which can be controlled via a slider or by inputting an exact percentage.

<figure><img src="/files/YhroY7rrGSGi4ZxWlEIO" alt="" width="563"><figcaption></figcaption></figure>

### Color range

A common use of raster data is to represent continuous measurements over an area, such as temperature or elevation. In these cases, a **`Color range`** style can be useful. Different Data Classification Methods can be used to apply colors to your data.

When using a **`Continuous`** classification method, the minimum and maximum data points will be set to three standard deviations from the mean. However, the range can be stretched by simply dragging the sliders under the histogram.

<figure><img src="/files/ShEvVnCfAjtGfDEo6k4O" alt="" width="563"><figcaption></figcaption></figure>

### Categories

This map type is useful for categorical data like geology, land use or crop type. Color palette metadata will be applied when available, although colors can always be manually selected.

Other styling options include controlling how colors are sorted in the legend or how many categories to show, whether all of them or only the most frequent ones.

<figure><img src="/files/4uekCxKGM2ba1IkRPALf" alt="" width="563"><figcaption></figcaption></figure>

### Hillshade

A **`Hillshade`** style can be used to represent elevation variations in a Digital Elevation Model. Coupled with a color range, it’s a great way of showing both absolute *and* relative elevation.

Both the angle of the light source (in [azimuth](https://en.wikipedia.org/wiki/Azimuth)) and the intensity of the hillshade are configurable.

<figure><img src="/files/T5jwSAlGLSDoww4qnw8a" alt="" width="563"><figcaption></figcaption></figure>

### Raster Algebra

Some [raster algebra](https://en.wikipedia.org/wiki/Map_algebra) metrics are available as presets for multi-band raster data:

<table data-header-hidden><thead><tr><th></th><th></th><th width="385"></th><th></th></tr></thead><tbody><tr><td><strong>Name</strong></td><td><strong>Acronym</strong></td><td><strong>Target</strong></td><td><strong>Bands</strong></td></tr><tr><td>Normalized Difference Vegetation Index</td><td>NDVI</td><td>Health and density of vegetation</td><td>Red and near infrared (NIR)</td></tr><tr><td>Normalized Difference Water Index</td><td>NDWI</td><td>Water bodies</td><td>Green and near infrared (NIR)</td></tr><tr><td>Normalized Difference Moisture Index</td><td>NDMI</td><td>Water content in vegetation</td><td>Near infrared (NIR) and short-wave infrared (SWIR)</td></tr></tbody></table>

<figure><img src="/files/i0cNvcdN3Cz53XjJSxJL" alt="" width="563"><figcaption></figcaption></figure>


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