Generate Spot Heights (Topographic Production)

Summary

Creates elevation point features based on contour tops and depressions. Elevation points are created in each top and depression. Point height values are populated based on a digital elevation model.

Usage

• This tool creates multiple points in areas with tops or depressions that have elevations of the same value. For example, if the tool finds two identical elevation values in different locations in the same top, it generates a point at each location.

• A top refers to an elevation completely surrounded by lower elevation contour lines. A depression refers to an elevation completely surrounded by higher elevation contour lines.

• Tops and depressions must be polylines that start and end at the same vertex. The tool will not create spot heights over contour lines that do not start and end at the same vertex.

• If more than one input raster is used, all input rasters must have the same cell size, band count, and pixel type. All input rasters should also use the same elevation units (meters or feet).

• The tool will not create spot heights over contour lines that do not overlap with point height values from the digital elevation model.

• Use the Map Scale parameter to refine the appearance of the spot heights to be optimized for print and display at the given scale. Specifying a scale will set the default value for the Z Factor parameter. When the Map Scale and Z Factor parameter values are left blank, the tool will use the 1:50,000 scale to calculate the values.

• When using an input raster with elevation units in meters, map scales of 1:250,000 or smaller use a z-factor of 3.28084 to convert meters to feet. The resulting value is rounded up to the next highest 5-foot interval.

Parameters

Dialog

Label	Explanation	Data Type
Input Contours	The contours from which spot heights will be computed.	Feature Layer
Input Raster(s)	The rasters used to derive the highest or lowest elevations in contour tops or depressions.	Raster Layer; Mosaic Layer
Target Spot Features	An existing point feature layer or feature class in which spot heights will be created.	Feature Layer
Contour Height Field	The field in the input contours that contains elevation values. The field type must be numeric.	Field
Spot Height Field	The field in the output spot heights where elevation values will be written.	Field
Spot Height Subtype	The spot height subtype value that will be assigned to new spot height features.	String
Area Of Interest (Optional)	The polygon features that represent the extent of the region where spot heights will be created. The tool uses the outer extent of the selected polygon features within the Area Of Interest parameter value. If this parameter is left blank, the tool uses the outer extent of the selected contour features within the Input Contours parameter value. If this parameter is left blank and no contour features are selected, the tool uses the extent of the raster.	Feature Layer
Map Scale (Optional)	Specifies the scale that will be used to optimize spot heights (the scale of the cartographic product that will be printed). Setting a scale will set the default of the Z Factor parameter to a value that is appropriate for the scale value. 1:5,000—The 1:5,000 cartographic product scale will be used. 1:10,000—The 1:10,000 cartographic product scale will be used. 1:12,500—The 1:12,500 cartographic product scale will be used. 1:25,000—The 1:25,000 cartographic product scale will be used. 1:50,000—The 1:50,000 cartographic product scale will be used. This is the default. 1:100,000—The 1:100,000 cartographic product scale will be used. 1:250,000—The 1:250,000 cartographic product scale will be used. 1:500,000—The 1:500,000 cartographic product scale will be used. 1:1,000,000—The 1:1,000,000 cartographic product scale will be used.	String
Z Factor (Optional)	The unit conversion factor that will be used when generating spot heights. The default is 1. The spot heights are generated based on the z-values in the input raster, which are often measured in units of meters or feet. With the default value of 1, the spot heights will be in the same units as the z-values of the input raster. To create spot heights in a unit other than that of the z-values, set an appropriate value for the z-factor. It is not necessary that the ground x,y and surface z-units be consistent for this tool. For example, if the elevation values in the input raster are in feet, but you want the spot heights to be generated in meters, set the z-factor to 0.3048 (1 foot = 0.3048 meters).	Double

Derived Output

Label	Explanation	Data Type
Updated Spot Heights	Spot height feature class where spot features were created.	Feature Layer

Python

arcpy.topographic.GenerateSpotHeights(in_contour_features, in_raster, target_spot_features, contour_height_field, spot_height_field, spot_height_subtype, {area_of_interest}, {scale}, {z_factor})

Name	Explanation	Data Type
in_contour_features	The contours from which spot heights will be computed.	Feature Layer
in_raster [in_raster,...]	The rasters used to derive the highest or lowest elevations in contour tops or depressions.	Raster Layer; Mosaic Layer
target_spot_features	An existing point feature layer or feature class in which spot heights will be created.	Feature Layer
contour_height_field	The field in the input contours that contains elevation values. The field type must be numeric.	Field
spot_height_field	The field in the output spot heights where elevation values will be written.	Field
spot_height_subtype	The spot height subtype value that will be assigned to new spot height features.	String
area_of_interest (Optional)	The polygon features that represent the extent of the region where spot heights will be created. The tool uses the outer extent of the selected polygon features within the area_of_interest parameter value. If this parameter is left blank, the tool uses the outer extent of the selected contour features within the in_contour_features parameter value. If this parameter is left blank and no contour features are selected, the tool uses the extent of the raster.	Feature Layer
scale (Optional)	Specifies the scale that will be used to optimize spot heights (the scale of the cartographic product that will be printed). Setting a scale will set the default of the z_factor parameter to a value that is appropriate for the scale value. 1:5,000—The 1:5,000 cartographic product scale will be used. 1:10,000—The 1:10,000 cartographic product scale will be used. 1:12,500—The 1:12,500 cartographic product scale will be used. 1:25,000—The 1:25,000 cartographic product scale will be used. 1:50,000—The 1:50,000 cartographic product scale will be used. This is the default. 1:100,000—The 1:100,000 cartographic product scale will be used. 1:250,000—The 1:250,000 cartographic product scale will be used. 1:500,000—The 1:500,000 cartographic product scale will be used. 1:1,000,000—The 1:1,000,000 cartographic product scale will be used.	String
z_factor (Optional)	The unit conversion factor that will be used when generating spot heights. The default is 1. The spot heights are generated based on the z-values in the input raster, which are often measured in units of meters or feet. With the default value of 1, the spot heights will be in the same units as the z-values of the input raster. To create spot heights in a unit other than that of the z-values, set an appropriate value for the z-factor. It is not necessary that the ground x,y and surface z-units be consistent for this tool. For example, if the elevation values in the input raster are in feet, but you want the spot heights to be generated in meters, set the z-factor to 0.3048 (1 foot = 0.3048 meters).	Double

Derived Output

Name	Explanation	Data Type
updated_spot_features	Spot height feature class where spot features were created.	Feature Layer

Code sample

GenerateSpotHeights example (stand-alone script)

This Python stand-alone sample code creates elevation point features based on contour tops and depressions.

# Name: GenerateSpotHeights_sample.py
# Description: Creates elevation point features based on contour tops and depressions

# Import System Modules
import arcpy

# Check Out Extensions
arcpy.CheckOutExtension('Foundation')

# Setting the environment
arcpy.env.overwriteOutput = True

# Setting Local Variables
input_contour_features = r'C:\Data\MGCP_TRD_4_4.gdb\MGCP_Delta\ContourL'
in_ratser = r'C:\Data\Monterey.dt2'
target_spot_features = r'C:\Data\MGCP_TRD_4_4.gdb\MGCP_Delta\ElevP'
contour_height_field = 'ZVH'
spot_height_field = 'ZVH'
spot_height_subtype = 'CA040_Spot_Elevation_Point'
area_of_interest = r'C:\Data\MapIndex.gdb\MapIndex\TLM50_Index'
scale = '1:50,000'
z_factor = '1'

# Making a feature layer from the Area of Interest features, and selecting a single feature based on the NRN field
arcpy.management.MakeFeatureLayer(area_of_interest_feature_class, 'AOI_Index')
arcpy.management.SelectLayerByAttribute('AOI_Index', 'NEW_SELECTION', "NRN = 'V795X16573'")

# Use the Generate Spot Heights tool to create spot heights for AOI
arcpy.topographic.GenerateSpotHeights(input_contour_features, in_raster, target_spot_features, contour_height_field, spot_height_field, spot_height_subtype, 'AOI_Index', scale, z_factor)

# Check In Extensions
arcpy.CheckInExtension('Foundation')

Environments

This tool does not use any geoprocessing environments.

Licensing information

• Basic: No
• Standard: No
• Advanced: Requires Production Mapping and Spatial Analyst