Topo to Raster by File (Spatial Analyst)
Summary
Interpolates a hydrologically correct raster surface from point, line, and polygon data using parameters specified in a file.
Usage
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The parameter file is structured with the input datasets listed first, followed by the various parameter settings, then the output options.
The input data identifies the input datasets and, where applicable, fields. There are nine types of input: Contours, Points, Sinks, Streams, Lakes, Boundaries, Cliffs, Exclusion, and Coastal polygons. You can use as many inputs as you want, within reason. The order in which the inputs are entered does not have any bearing on the outcome. <Path> indicates a path to a dataset, <Item> indicates a field name, and <#> indicates a value to be entered.
The following table lists all of the parameters, the definition of each, and their syntax.
Parameter
Definition
Syntax
Input datasets:
Contours
Contour line dataset with item containing height values.
Contour <Path> <Item> Points
Point dataset with item containing height values.
Point <Path> <Item> Sinks
Point dataset containing sink locations. If the dataset has elevation values for the sinks, specify that field name as the <Item>. If only the locations of the sinks are to be used, use NONE for <Item>.
Sink <Path> <Item> Streams
Stream line dataset. Height values are not necessary.
Stream <Path> Lakes
Lake polygon dataset. Height values are not necessary.
Lake <Path> Boundary
Boundary polygon dataset. Height values are not necessary.
Boundary <Path> Cliff
Line dataset of the cliffs. There is no Field option for Cliff.
Cliff <Path> Exclusion
Exclusion polygon dataset of the areas in which the input data should be ignored. There is no Field option for Exclusion.
Exclusion <Path> Coast
Coast polygon dataset containing the outline of a coastal area. There is no Field option for Coast.
Boundary <Path> Parameter settings:
Enforce
Controls whether drainage enforcement is applied.
ENFORCE <ON | OFF | ON_WITH_SINK> Datatype
Primary type of input data.
DATATYPE <CONTOUR | SPOT> Iterations
The maximum number of iterations the algorithm performs.
ITERATIONS <#> Roughness penalty
The measure of surface roughness.
ROUGHNESS_PENALTY <#> Profile curvature roughness penalty
The profile curvature roughness penalty is a locally adaptive penalty that can be use to partly replace total curvature.
PROFILE_PENALTY <#> Discretisation error factor
The amount to adjust the data smoothing of the input data into a raster.
DISCRETE_ERROR_FACTOR <#> Vertical standard error
The amount of random error in the z-values of the input data.
VERTICAL_STANDARD_ERROR <#> Tolerances
The first reflects the accuracy of elevation data in relation to surface drainage, and the other prevents drainage clearance through unrealistically high barriers.
TOLERANCES <#> <#> Z-Limits
Lower and upper height limits.
ZLIMITS <#> <#> Extent
Minimum x, minimum y, maximum x, and maximum y coordinate limits.
EXTENT <#> <#> <#> <#> Cell size
The resolution of the final output raster.
CELL_SIZE <#> Margin
Distance in cells to interpolate beyond the specified output extent and boundary.
MARGIN <#> Outputs:
Output stream features
The output line feature class of stream polyline features and ridge line features.
OUT_STREAM Output sink features
The output point feature class of the remaining sink point features.
OUT_SINK Output diagnostics file
The location and name of the diagnostics file.
OUT_DIAGNOSTICS <Path> Output residual point features
The output point feature class of all the large elevation residuals as scaled by the local discretisation error.
OUT_RESIDUALS Output stream and cliff point features
The output point feature class of locations where possible stream and cliff errors occur.
OUT_STREAM_CLIFF_ERRORS Output contour error point features
The output point feature class of possible errors pertaining to the input contour data.
OUT_CONTOUR_ERRORS -
Do not specify paths for the optional output feature datasets in the parameter file. Use the Output stream polyline features and Output remaining sink point features in the tool dialog box to identify these outputs.
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The contents of an example parameter file are:
Contour D:\data\contours2\arc HEIGHT Point D:\data\points2\point SPOTS Sink D:\data\sinks_200.shp Stream D:\data\streams\arc Lake D:\data\lakes\polygon Boundary D:\data\clipcov\polygon Cliff D:\data\cliffs.shp ENFORCE ON DATATYPE CONTOUR ITERATIONS 40 ROUGHNESS_PENALTY 0.0 PROFILE_PENALTY 0.5 DISCRETE_ERROR_FACTOR 1.0 VERTICAL_STANDARD_ERROR 0.0 TOLERANCES 2.5 100.0 ZLIMITS -2000.0 13000.0 EXTENT -810480.625 8321785.0 810480.625 10140379.0 CELL_SIZE 1800.00000000000 MARGIN 20 OUT_DIAGNOSTICS D:\data\ttr_diag.txt
Syntax
| Parameter | Explanation | Data Type |
in_parameter_file |
The input ASCII text file containing the inputs and parameters to use for the interpolation. The file is typically created from a previous run of Topo to Raster with the optional output parameter file specified. In order to test the outcome of changing the parameters, it is easier to make edits to this file and rerun the interpolation than to correctly issue the Topo to Raster tool each time. | File |
out_stream_features (Optional) |
Output feature class of stream polyline features. The polyline features are coded as follows:
| Feature Class |
out_sink_features (Optional) |
Output feature class of remaining sink point features. | Feature Class |
out_residual_feature (Optional) |
The output point feature class of all the large elevation residuals as scaled by the local discretisation error. All the scaled residuals larger than 10 should be inspected for possible errors in input elevation and stream data. Large-scaled residuals indicate conflicts between input elevation data and streamline data. These may also be associated with poor automatic drainage enforcements. These conflicts can be remedied by providing additional streamline and/or point elevation data after first checking and correcting errors in existing input data. Large unscaled residuals usually indicate input elevation errors. | Feature Class |
out_stream_cliff_error_feature (Optional) |
The output point feature class of locations where possible stream and cliff errors occur. The locations where the streams have closed loops, distributaries and streams over cliffs can be identified from the point feature class. Cliffs with neighboring cells that are inconsistent with the high and low sides of the cliff are also indicated. This can be a good indicator of cliffs with incorrect direction. Points are coded as follows:
| Feature Class |
out_contour_error_feature (Optional) |
The output point feature class of possible errors pertaining to the input contour data. Contours with bias in height exceeding five times the standard deviation of the contour values as represented on the output raster are reported to this feature class. Contours that join other contours with a different elevation are flagged in this feature class by the code 1; this is a sure sign of a contour label error. | Feature Class |
Return Value
| Name | Explanation | Data Type |
| out_surface_raster |
The output interpolated surface raster. | Raster |
Code Sample
This example creates a hydrologically correct TIFF surface raster from a parameter file defining the input point, line, and polygon data.
import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outTTRByFile = TopoToRasterByFile("topotorasterbyfile.txt",
"C:/sapyexamples/output/out_streams.shp", "#",
"C:/sapyexamples/output/out_resids.shp")
outTTRByFile.save("C:/sapyexamples/output/ttrbyfout.tif")
This example creates a hydrologically correct Grid surface raster from a parameter file defining the input point, line, and polygon data.
# Name: TopoToRasterByFile_Ex_02.py
# Description: Interpolates a hydrologically correct
# surface from point, line, and polygon data using
# parameters specified in a file.
# Requirements: Spatial Analyst Extension
# Import system modules
import arcpy
from arcpy import env
from arcpy.sa import *
# Set environment settings
env.workspace = "C:/sapyexamples/data"
# Set local variables
inParameterFile = "topotorasterbyfile.txt"
# Check out the ArcGIS Spatial Analyst extension license
arcpy.CheckOutExtension("Spatial")
# Execute TopoToRasterByFile
outTTRByFile = TopoToRasterByFile(inParameterFile, "#", "C:/sapyexamples/output/out_resids2.shp")
# Save the output
outTTRByFile.save("C:/sapyexamples/output/ttrbyfout02")