Hillshade 

Release 9.2
Last modified January 3, 2008 
Print all topics in : "Surface (Spatial Analyst)" 
Computes hillshade values for a raster surface by considering the illumination angle and shadows.
Learn more about how Hillshade works
Illustration
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 zfactor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate zfactors for particular latitudes are:
Latitude Zfactor 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 threedimensional views of the hillshaded surface by draping the output raster using ArcGIS 3D Analyst.
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 zfactor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate zfactors for particular latitudes are:
Latitude Zfactor 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 threedimensional 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 zfactor for that latitude. If your x,y units are decimal degrees and your z units are meters, some appropriate zfactors for particular latitudes are:
Latitude Zfactor 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}
Parameter  Explanation  Data Type 
<in_raster> 
Input raster.

Composite Geodataset 
<out_raster> 
The raster to be created. The hillshade raster has an integer value range of 0 to 255.

Raster Dataset 
{azimuth} 
Azimuth angle of the light source. The azimuth is expressed in positive degrees from 0 to 360, measured clockwise from north. The default is 315 degrees.

Double 
{altitude} 
Altitude angle of the light source above the horizon. The altitude is expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead. The default is 45 degrees.

Double 
{NO_SHADOWS  SHADOWS} 
Type of shaded relief to be generated.

Boolean 
{z_factor} 
The number of ground x,y units in one surface z unit. The zfactor adjusts the units of measure for the z units when they are different from the x,y units of the input surface. The zvalues of the input surface are multiplied by the zfactor when calculating the final output surface. If the x,y units and z units are in the same units of measure, the zfactor is 1. This is the default. If the x,y units and z units are in different units of measure, the zfactor must be set to the appropriate factor, or the results will be incorrect. For example, if your z units are feet and your x,y units are meters, you would use a zfactor of 0.3048 to convert your z units from feet to meters (1 foot = 0.3048 meter).

Double 
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)
Parameter  Explanation  Data Type 
in_raster (Required) 
Input raster.

Composite Geodataset 
out_raster (Required) 
The raster to be created. The hillshade raster has an integer value range of 0 to 255.

Raster Dataset 
azimuth (Optional) 
Azimuth angle of the light source. The azimuth is expressed in positive degrees from 0 to 360, measured clockwise from north. The default is 315 degrees.

Double 
altitude (Optional) 
Altitude angle of the light source above the horizon. The altitude is expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead. The default is 45 degrees.

Double 
model_shadows (Optional) 
Type of shaded relief to be generated.

Boolean 
z_factor (Optional) 
The number of ground x,y units in one surface z unit. The zfactor adjusts the units of measure for the z units when they are different from the x,y units of the input surface. The zvalues of the input surface are multiplied by the zfactor when calculating the final output surface. If the x,y units and z units are in the same units of measure, the zfactor is 1. This is the default. If the x,y units and z units are in different units of measure, the zfactor must be set to the appropriate factor, or the results will be incorrect. For example, if your z units are feet and your x,y units are meters, you would use a zfactor of 0.3048 to convert your z units from feet to meters (1 foot = 0.3048 meter).

Double 
# 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})
Parameter  Explanation 
<grid>  The input raster from which the shaded relief is derived. 
{azimuth}  The azimuth angle of the light source.
The azimuth is expressed in positive degrees from 0 to 360, measured clockwise from north. The default is 315 degrees. 
{altitude}  The slope or angle of the illumination source above the horizon.
The slope is expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead. The default is 45 degrees. 
{ALL  SHADE  SHADOW}  Keyword specifying the type of shaded relief to be generated.

{z_factor}  The number of ground x,y units in one surface z unit.
The <grid> z units are multiplied by the specified {z_factor} to convert the output raster z units to another unit of measure. By default, {z_factor} of 1 is applied. Higher zvalues will result in a more exaggerated relief (surface) and, thus, in a more extreme shading. 
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
Parameter  Explanation 
geoDataset  The input Raster, RasterDataset, RasterBand, or RasterDescriptor from which the shaded relief is derived. 
azimuth  The azimuth angle of the light source.
The azimuth is expressed in positive degrees from 0 to 360, measured clockwise from north. A commonly used azimuth is 315 degrees. 
altitude  The slope or angle of the illumination source above the horizon.
The slope is expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly overhead. A commonly used altitude is 45 degrees. 
inModelShadows  A Boolean specifying the type of shaded relief to be generated.
If True, the output shaded relief raster will consider both local illumination angles and shadows. The output raster contains values ranging from 0 to 255, with 0 representing the shadow areas, and 255 the brightest. If False, the output shaded relief raster only considers local illumination angles; the effects of shadows are not considered. The output raster contains values ranging from 0 to 255, with 0 representing the darkest areas, and 255 the brightest. 
[zFactor]  The geoDataset z units are multiplied by the specified [zFactor] to convert the output raster z units to another unit of measure.
If no [zFactor] is specified, a [zFactor] of 1 is applied. Higher zvalues will result in a more exaggerated relief (surface) and, thus, in a more extreme shading. 
' 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)