ArcMap

Create Ortho Corrected Raster Dataset

Summary

Incorporates elevation data and image metadata to accurately line up imagery.

Learn more about orthorectifying a raster dataset

Usage

  • To orthocorrect a raster dataset, the raster must have rational polynomial coefficients (RPCs) associated with it.

  • For a more accurate result, you should use the digital elevation model (DEM) option for elevation. A DEM should be used 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, or any geodatabase raster dataset.

  • Satellite RPCs require the use of 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

CreateOrthoCorrectedRasterDataset_management (in_raster, out_raster_dataset, Ortho_type, constant_elevation, {in_DEM_raster}, {ZFactor}, {ZOffset}, {Geoid})
ParameterExplanationData Type
in_raster

Select the raster dataset that you want to orthorectify. The raster must have rational polynomial coefficients (RPCs) in its metadata.

Raster Layer
out_raster_dataset

Specify a name, location and format for the dataset you are creating.

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
  • 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 type and Compression Quality within the Environment Settings.

Raster Dataset
Ortho_type

Use a Digital Elevation Model (DEM) or specify a value that represents the average elevation across your image.

  • CONSTANT_ELEVATION —Uses a specified elevation value.
  • DEM —Uses a specified digital elevation model raster.
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 digital elevation model 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 in meters, the Z Factor should be set to 1. If your vertical units are in feet, the Z Factor should be set to 0.3048. If any other vertical units are used, use the Z Factor 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 could be used to offset elevation values that do not start at sea level.

Double
Geoid
(Optional)

The geoid correction is required by RPCs that reference ellipsoidal heights. Most elevation datasets are referenced to sea level orthometric heights, so this correction would be 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

  • ArcGIS Desktop Basic: Yes
  • ArcGIS Desktop Standard: Yes
  • ArcGIS Desktop Advanced: Yes

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