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 function 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 functions are available for image services of DEMs (digital elevation models, or pixel based bare earth elevation).
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 function 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|
Once Arcmap is open,
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.
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.