Hillshade

Map Algebra:
OutRas = Hillshade(InRas1, 99, 33)

Command Line:
Hillshade_sa InRas1 OutRas 99 33

Usage tips

Command line and Scripting

• The Hillshade tool creates a shaded relief raster from a raster. The illumination source is considered at infinity.

• The hillshade raster has an integer value range of 0 to 255.

• Two types of shaded relief rasters can be output. If the Model shadows check box is unchecked, the output raster only considers local illumination angle. If the Model shadows check box is checked, the output raster considers the effects of both local illumination angle and shadow.

• The analysis of shadows is done by considering the effects of the local horizon at each cell. Raster cells in shadow are assigned a value of zero.

• To create a raster of the shadow areas only, use the Con, Reclassify, or Extract By Attribute tool to separate the value zero from the other hillshade values. Hillshade must have the Model shadows check box checked.

• If the input raster is in a spherical coordinate system, such as decimal degrees, the results from Hillshade may look peculiar. This is due to the difference in measure between the horizontal ground units and the elevation z units. Since the length of a degree of longitude changes with latitude, you will need to specify an appropriate z-factor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate z-factors for particular latitudes are:

      Latitude     Z-factor
       0           0.00000898
      10           0.00000912
      20           0.00000956
      30           0.00001036
      40           0.00001171
      50           0.00001395
      60           0.00001792
      70           0.00002619
      80           0.00005156

• You can create dramatic three-dimensional views of the hillshaded surface by draping the output raster using ArcGIS 3D Analyst.

• The following environment settings affect this tool:

  • General: Current Workspace, Scratch Workspace, Output Coordinate system, Output Extent, Snap Raster.
  • Raster Analysis: Cell size, Mask.
  • Raster Storage: See the Raster Storage settings for the particular output raster format selected.

Map Algebra

• Hillshade creates a shaded relief raster from an elevation raster. The illumination source is considered to be at infinity.

• The hillshade raster has an integer value range of 0 to 255.

• Three types of shaded relief rasters can be output. The SHADE option only considers local illumination angle. The SHADOW option only considers whether or not the cell is in shadow. The ALL option considers the effects of both local illumination angle and shadow.

• The analysis of shadows is done by considering the effects of the local horizon at each cell. Raster cells in shadow are assigned a value of zero.

• If the input raster is in a spherical coordinate system, such as decimal degrees, the results from Hillshade may look peculiar. This is due to the difference in measure between the horizontal ground units and the elevation z units. Since the length of a degree of longitude changes with latitude, you will need to specify an appropriate z-factor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate z-factors for particular latitudes are:

      Latitude     Z-factor
       0           0.00000898
      10           0.00000912
      20           0.00000956
      30           0.00001036
      40           0.00001171
      50           0.00001395
      60           0.00001792
      70           0.00002619
      80           0.00005156

• You can create dramatic three-dimensional views of the hillshaded surface by draping the output raster using ArcGIS 3D Analyst.

• Learn more about how to specify the input raster dataset in the Map Algebra expression of Raster Calculator.

ArcObjects

• Hillshade creates a shaded relief raster from an elevation raster. The illumination source is considered to be at infinity.

• The hillshade raster has an integer value range of 0 to 255.

• Two types of shaded relief rasters can be output. With inModelShadows TRUE, the effects of both local illumination angle and shadow are considered. With inModelShadows FALSE, only local illumination angle is considered.

• The analysis of shadows is done by considering the effects of the local horizon at each cell. Raster cells in shadow are assigned a value of zero.

• If the input raster is in a spherical coordinate system, such as decimal degrees, the results from Hillshade may look peculiar. This is due to the difference in measure between the horizontal ground units and the elevation z units. Since the length of a degree of longitude changes with latitude, you will need to specify an appropriate z-factor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate z-factors for particular latitudes are:

      Latitude     Z-factor
       0           0.00000898
      10           0.00000912
      20           0.00000956
      30           0.00001036
      40           0.00001171
      50           0.00001395
      60           0.00001792
      70           0.00002619
      80           0.00005156

• The output from the ArcObjects method is a raster object

Command line syntax
An overview of the Command Line window
Hillshade_sa <in_raster> <out_raster> {azimuth} {altitude} {NO_SHADOWS | SHADOWS} {z_factor}

Command line example

Hillshade_sa C:/data/dem C:/data/hillshade 325 50

Scripting syntax
About getting started with writing geoprocessing scripts
Hillshade_sa (in_raster, out_raster, azimuth, altitude, model_shadows, z_factor)

Script example

# Hillshade_sample.py
# Description: 
#   Computes hillshade values for a raster surface.
# Requirements: None
# Author: ESRI
# Date: Sept 6, 2005
# Import system modules
import arcgisscripting

# Create the Geoprocessor object
gp = arcgisscripting.create()

try:
    # Set local variables
    InRaster = "C:/data/dem"
    OutRaster = "C:/data/hillshade"
    InAzimuth = "325"
    InAltitude = "50"

    # Check out ArcGIS Spatial Analyst extension license
    gp.CheckOutExtension("Spatial")

    # Process: Hillshade
    gp.Hillshade_sa(InRaster, OutRaster, InAzimuth, InAltitude)

except:
    # If an error occurred while running a tool, then print the messages.
    print gp.GetMessages()

Map Algebra syntax
Hillshade(<grid>, {azimuth}, {altitude}, {ALL | SHADE | SHADOW}, {z_factor})

Map Algebra example

hillshade(ingrid)
hillshade(ingrid, 180, 33)
hillshade(ingrid, #, 59, shade)
hillshade(ingrid, 90, 15, shadow, 2.5)
hillshade(ingrid, 213, 20, #, 0.5)

ArcObjects syntax
ISurfaceOp::Hillshade (geoDataset As IGeoDataset, azimuth As Double, altitude As Double, inModelShadows As Boolean, [zFactor As Variant]) As IGeoDataset

ArcObjects example

' Create the RasterSurfaceOp object
Dim pSurfaceOp As ISurfaceOp
Set pSurfaceOp = New RasterSurfaceOp

' Create the input raster object
Dim pInputDataset As IGeoDataset

' Calls function to open the raster dataset from disk
Set pInputDataset = OpenRasterDataset("D:\SpatialData", "inputraster")

' Create the output dataset object
Dim pOutputDataset As IGeoDataset

' Calls the method
Set pOutputDataset = pSurfaceOp.Hillshade (pInputDataset, 315, 45, True)