ArcMap

Create Ortho Corrected Raster Dataset

Summary

Creates an orthocorrected raster dataset by incorporating elevation data and the rational polynomial coefficients (RPC) associated with satellite data to accurately line up imagery.

Learn more about orthorectifying a raster dataset

Usage

  • To orthocorrect a raster dataset, the raster must have RPCs associated with it.

  • For a more accurate result, use the digital elevation model (DEM) option for elevation. Use a DEM in the orthocorrection process to correct geometric errors caused by relief displacement.

  • Using a constant elevation value for the Orthorectification Type parameter will not yield accurate results and should only be used when no DEM is available and approximate spatial accuracy is acceptable.

  • You can save your output to BIL, BIP, BMP, BSQ, DAT, Esri Grid , GIF, IMG, JPEG, JPEG 2000, PNG, TIFF, MRF, CRF, or any geodatabase raster dataset.

  • Satellite RPCs require a DEM referenced to ellipsoidal heights, but most elevation data (such as USGS NED and ArcGIS Online World Elevation) are referenced to sea level orthometric heights. Check the Geoid parameter (GEOID in Python) to orthorectify with RPCs unless your DEM is referenced to an ellipsoidal height.

Syntax

arcpy.management.CreateOrthoCorrectedRasterDataset(in_raster, out_raster_dataset, Ortho_type, constant_elevation, {in_DEM_raster}, {ZFactor}, {ZOffset}, {Geoid})
ParameterExplanationData Type
in_raster

The raster dataset to orthorectify. The raster must have RPCs in its metadata.

Raster Layer
out_raster_dataset

The name, location, and format of the dataset to be created.

When storing the raster dataset in a file format, you need to specify the file extension:

  • .bil—Esri BIL
  • .bip—Esri BIP
  • .bmp—BMP
  • .bsq—Esri BSQ
  • .dat—ENVI DAT
  • .gif—GIF
  • .img—ERDAS IMAGINE
  • .jpg—JPEG
  • .jp2—JPEG 2000
  • .png—PNG
  • .tif—TIFF
  • .mrf—MRF
  • .crf—CRF
  • No extension for Esri Grid

When storing a raster dataset in a geodatabase, do not add a file extension to the name of the raster dataset.

When storing your raster dataset to a JPEG file, a JPEG 2000 file, or a geodatabase, you can specify a Compression Type and Compression Quality in the Environments.

Raster Dataset
Ortho_type

The DEM or specified value that represents the average elevation across the image.

  • CONSTANT_ELEVATION —A specified elevation value will be used.
  • DEM —A specified digital elevation model raster will be used.
String
constant_elevation

The constant elevation value to be used when the Ortho_type parameter is CONSTANT_ELEVATION.

If a DEM is used in the orthocorrection process, this value is not used.

Double
in_DEM_raster
(Optional)

The DEM raster to be used for orthorectification when the Ortho_type parameter is DEM.

Mosaic Layer; Raster Layer
ZFactor
(Optional)

The scaling factor used to convert the elevation values in the DEM.

If your vertical units are meters, set the ZFactor to 1. If your vertical units are feet, set the Factor to 0.3048. If any other vertical units are used, use the ZFactor to scale the units to meters.

Learn more about the Z Factor

Double
ZOffset
(Optional)

The base value to be added to the elevation value in the DEM. This can be used to offset elevation values that do not start at sea level.

Double
Geoid
(Optional)

Specifies whether the geoid correction required by RPCs that reference ellipsoidal heights will be made. Most elevation datasets are referenced to sea level orthometric heights, so this correction is required in these cases to convert to ellipsoidal heights.

  • NONE —No geoid correction is made. Use NONE only if your DEM is already expressed in ellipsoidal heights.
  • GEOID —A geoid correction will be made to convert orthometric heights to ellipsoidal heights (based on EGM96 geoid).
Boolean

Code sample

CreateOrthoCorrectedRasterDataset example 1 (Python window)

This is a Python sample for the CreateOrthoCorrectedRasterDataset tool.

import arcpy
arcpy.CreateOrthoCorrectedRasterDataset_management("c:/data/RPCdata.tif",
                                                   "c:/data/orthoready.tif",
                                                   "DEM", "#", "c:/data/DEM.img",
                                                   "#", "10", "GEOID")
CreateOrthoCorrectedRasterDataset example 2 (stand-alone script)

This is a Python script sample for the CreateOrthoCorrectedRasterDataset tool.

##====================================
##Create Ortho Corrected Raster Dataset
##Usage: CreateOrthoCorrectedRasterDataset_management in_raster out_raster_dataset
##                                                    CONSTANT_ELEVATION | DEM constant_ elevation
##                                                    in_DEM_raster {ZFactor} {ZOffset} {NONE | GEOID}

import arcpy
arcpy.env.workspace = "C:/Workspace"

##Ortho correct with Constant elevation
arcpy.CreateOrthoCorrectedRasterDataset_management("ortho.img", "orthoready.tif",\
                                                   "CONSTANT_ELEVATION", "30", "#",\
                                                   "#", "#", "#")

##Ortho correct with DEM image and Z factors
arcpy.CreateOrthoCorrectedRasterDataset_management("ortho.img", "orthoready_dem.tif",\
                                                   "DEM", "#", "dem.img", "#", "10", "GEOID")

Environments

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes

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