1. Data
  2. CT Elevation Data
  3. Raster Processing Templates: Accessing and Applying for Elevation

Raster Processing Templates: Accessing and Applying for Elevation

A raster is a geographic dataset that consists of pixels which 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 processing operation that can be applied to a raster. 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

They are evident by the year at the end. The aspect, elevation, hillshade, shaded relief and slope are based on the 2016 DEMs and already have a processing template applied.

Statewide 2016 More info REST
Central 2014 More info REST
Coast 2012 More info REST
East 2010 More info REST
Northwest 2011 More info REST
Southeast 2011 More info REST
Southwest 2011 More info REST

Hillshade Services on CT ECO with Raster Functions

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. If you need a different angle and do not have ArcGIS Pro, please email us (information in the footer). These raster processing templates are available with the Elevation service and the Hillshade SE service.

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

Apply a Raster Processing Template in ArcGIS Pro or ArcGIS Online

The most recent CT elevation does not have separate services for hillshade, shaded relief, or slope. However, these can be accessed in ArcGIS Pro and ArcGIS Online using the following instructions:

ArcGIS Pro

  • Add the Elevation image service from CT ECO to the map (detailed instructions here)
  • Click on the layer name in the Contents pane. Once clicked, the Data tab will appear at the top of the screen.
  • Click Data and then Processing Templates. There are a variety of options to choose from, including hillshade! Choose the desired processing template. Note that the same service can be added multiple times with different processing templates applied.RasterPT_arcpro

ArcGIS Online

  • Add the Elevation image service from CT ECO to the map (detailed instructions here)
  • Click on the options icon options_3dots  next to the layer name in the Layers pane.
  • Click Show Properties and then navigate to Processing Templates RasterPT_agolicon. Once again, there are a variety of options to choose from, including hillshade! Choose the desired processing template and select Done. Note that the same service can be added multiple times with different processing templates applied.RasterPT_agol

 

    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.