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).
Elevation Services on CT ECO with Raster Processing Templates
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 Services on CT ECO with Raster Processing Templates
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
Raster Processing Templates
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.
Apply a Raster Processing Template in ArcGIS Pro or ArcGIS Online
Some elevation services included raster processing templates that can be applied to the base elevation service. To access and apply a processing template that is included with the service in ArcGIS Pro or ArcGIS Online, follow the instructions belo
Apply a Raster Processing Template in ArcGIS Pro
- 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.
Apply a Raster Processing Template in ArcGIS Online
- Add the Elevation image service from CT ECO to the map (instructions)
- Click on the options icon
next to the layer name in the Layers pane.
- Select Show Properties and then navigate to Processing Templates
. Click on the desired processing template and select Done. Note that the same service can be added multiple times with different processing templates applied.