Raster Processing Templates: Accessing and Applying for Elevation

A raster is a geographic dataset that consists of pixels that are organized in rows and columns. Each pixel has a value, such as elevation. Each pixel also has an x and y coordinate which gives it a location.

A raster processing template is a defined string of raster functions that can be applied to an image service in ArcGIS Pro or ArcGIS Online. The on-the-fly application does not change the underlying raster data, just how it is displayed. On CT ECO, raster processing templates are available for image services of DEMs (digital elevation models, or pixel based bare earth elevation).

The following services included raster processing templates. If an additional processing template would be helpful for you, please let us know (contact info in footer).

Service	Processing templates included
Statewide 2023	aspect, hillshade, hillshade multidirectional, shaded relief, slope	More info
Statewide 2023 CT State Plane NAD83 2011	aspect, hillshade, hillshade multidirectional, shaded relief, slope	More info
Statewide 2016	aspect, hillshade, shaded relief, slope, slope stretch	More info
Statewide 2016 CT State Plane NAD83 2011	slope percent rise, aspect, hillshade, shaded relief, slope, slope_stretch	More info
Central 2014	aspect, hillshade, shaded relief, slope, slope stretch	More info
Coast 2012	aspect, hillshade, shaded relief, slope, slope stretch	More info
East 2010	aspect, hillshade, shaded relief, slope, slope stretch	More info
Northwest 2011	aspect, hillshade, shaded relief, slope, slope stretch	More info
Southeast 2011	aspect, hillshade, shaded relief, slope, slope stretch	More info
Southwest 2011	aspect, hillshade, shaded relief, slope, slope stretch	More info

Hillshade is a way to look at topography by adding an illumination source. Just as the sun moves across the sky, the illumination source can be set to any azimuth, or angular direction like a circle where 0 is North, 90 is east, 180 is south and 270 is west. Different features are visible on the hillshade depending on the illumination angle which is why multiple hillshade processing templates are included for user application in ArcGIS Online and ArcGIS Pro. All templates have an altitude of 45 and a Z factor of 2. These raster processing templates are available with the Elevation service, the Hillshade service, and the Hillshade SE service.

Note. The Hillshade_SE service is the same as applying the Hillshade SE 135 processing template to the Elevation or Hillshade service. We publish the Hillshade_SE on its own to make it easier and more accessible.

	Azimuth
Hillshade default	315 (NW)
Hillshade E 90	90
Hillshade NE 45	45
Hillshade SE 135	135
Hillshade multidirectional

Traditional Hillshade vs Multidirectional Hillshade

Traditional hillshade is calculated using an illumination source from one direction that uses the altitude and azimuth properties to specify the sun's position. The multidirectional method combines light from multiple sources to represent the hillshaded terrain. The advantage of the multidirectional hillshade method is that more detail is displayed in areas typically affected by oversaturation and deep shadows than when using the traditional hillshade method. Source

Aspect can be thought of as slope direction. The values of the aspect layer are the compass direction of the slope with north being 0, east being 90, south being 180 and west being 270.

Hillshade is a grayscale model of terrain with the sun's angle taken into account for shading the terrain. Hillshade varies by illumination angle so multiple hillshade functions are available.

Shaded Relief is a color representation of the terrain that takes the sun's angle into account.

Slope represents the rate of change of elevation. The output is shown in degrees from 0 to 90.

Add the Elevation image service from CT ECO to the map (instructions).
Click on the layer name in the Contents pane. Select the Data tab at the top of the screen.
Find Processing Templates and click on it to see the available processing templates. Choose the desired processing template by clicking on it which applies it to the elevation service. Note that the same service can be added multiple times with different processing templates applied.