In the ERDAS IMAGINE Workspace, selecting which geometric model you wish to solve for the raster image to be rectified is done in this dialog, as part of the raster image rectification process. Use this dialog to create a new geometric model from a template, select an existing geometric model, or use an image that is calibrated.

- Path to Dialog
- Vertical Datum Alignment
- Dialog Description

To learn how to rectify imagery see Rectifying an Image and Orthorectify without GCPs.

Path to Dialog

This dialog opens when you:

- Click Transform & Orthocorrect group > Control Points in the Multispectral, Panchromatic, Relief, or Thematic tabs.
- Click Transform & Ortho > Ortho with Model Selection in the Multispectral, Panchromatic, Relief, or Thematic tabs.
- Click Raster tab > Geometric Calibration > Calibrate with Sensor Model and Terrain
- Click Raster tab > Geometric Calibration > Orthorectify without GCP

Vertical Datum Alignment

Most 3D Transform models automatically adjust in real-time any vertical datum mismatch between the DEM and the respective model, beginning with IMAGINE 2010. A few models require vertical datum alignment as described below.

Models where a Vertical Datum Mismatch Cannot be Automatically Addressed

Vertical Datum Cannot be Specified

- Direct Linear Transform
- Landsat
- SPOT 1 - 4

The 3D transform models Landsat, Direct Linear Transform, and SPOT 1-4 expect the vertical datum of the DEM to be the same as the vertical datum of the respective model. If your DEM refers to a different vertical datum (for example, the transform model is expecting a vertical datum of WGS84 while the DEM has a vertical datum of Mean Sea Level / EGM96), use Recalculate Elevation for Images to change the vertical datum in your DEM to match that of the 3D transform model. This applies only when using the Geometric Correction tool or IMAGINE AutoSync.

Vertical Datum is Unknown

Some models, such as Camera, do not specify an internal default vertical datum. If you do not specify the vertical datum, then these models will use the vertical datum of the DEM. If Z control points or exterior orientation information use a different vertical datum than the DEM uses, then this automatic assumption made by the software would be incorrect. For models with an unknown vertical datum, first manually set all variables (that is, exterior orientation, control, and DEM vertical datums) to the same vertical datum, and then the single vertical datum should be specified.

Models where a Vertical Datum Mismatch Can be Automatically Addressed

Most sensor models contain an internal default value for a vertical datum. This value is the initial vertical datum that is reported in the dialog. These models are expecting your DEM and your solution to use the same vertical datum. If your DEM refers to a different vertical datum than the model is expecting, ERDAS IMAGINE will recalculate in real-time and provide the solution expressed in the vertical datum of the model.

You can override the default value of the output model by entering the desired values in the Vertical options section. ERDAS IMAGINE will recalculate and provide the output solution in the vertical datum that you specified.

Dialog Description

Model List Select the model from the Select Geometric Model list.

Saved Model Open an existing geometric model saved from a previous session. The File Selector opens.

Existing Calibration(Calibrated image only) Resample the image using the calibration data associated with it. The Resample dialog opens. The Existing Calibration option is not available when opened from the IMAGINE AutoSync > Project Properties > Geometric Model tab.

Select Geometric Model: [list]Select a geometric model template from the list of available model types.

The Multipoint Geometric Correction workspace opens and the GCP Tool Reference Setup dialog opens for you to provide the specific parameters for creating a new geometric model. The new geometric model may be saved for later use.

Camera Use this model to create a custom geometric correction model for a specific camera. The Camera model allows orthorectification of any camera data with a single perspective center. It is derived based on colinearity equations. The elevation data is used in the rectification process to remove relief displacement. The Camera Model Properties dialog opens after determining the GCP collection method.

Direct Linear Transform (DLT) The Direct Linear Transform (DLT) aids in gathering information as a 3D single perspective. This transformational method is useful for orthocorrecting imagery when there is no interior information available for the imagery, such as when your imagery comes from historical archive film. The Direct Linear Transform (DLT) Model Properties dialog opens after determining the GCP collection method.

DPPDB Use the DPPDB model for Digital Point Positioning Data Base product. The DPPDB model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The DPPDB Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Orbital Pushbroom The Orbital Pushbroom model uses orbital ephemeris information. Use this model for models of orbital pushbroom sensors that are not specifically listed in the dialog. The Orbital Pushbroom dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

ALOS PRISM - Orbital Pushbroom Use this model for ALOS PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) sensor data in which RPC data is not available. The ALOS PRISM - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

ASTER - Orbital Pushbroom Use this model for ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) sensor data. ASTER captures high resolution data in the visible to thermal infrared wavelength spectrum and provides stereo viewing capability for DEM creation. The ASTER - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

EROS - Orbital Pushbroom Use this model for Earth Remote Observation Satellite (EROS) sensor data. EROS A imaging techniques offer panchromatic images in basic type and as stereo pairs. EROS B imaging techniques offer panchromatic images in basic, stereo pair, triplet, and mosaic types. The EROS - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

FORMOSAT2 - Orbital Pushbroom Use this model for data collected by FORMOSAT-2 satellite, developed by National Space Organization (NSPO) of Taiwan. FORMOSAT-2 onboard sensors include a Remote Sensing Instrument and ISUAL (Imager of Sprites and Upper Atmospheric Lightning). The FORMOSAT2 - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

GeoEye/OrbView - Orbital Pushbroom Use this model for GeoEye or OrbView images in which RPC data is not available. This model is for data collected by GeoEye-1 satellite, developed by GeoEye, a company formed through the combination of ORBIMAGE and Space Imaging, as well as data collected by OrbView-3 satellite, built for Orbital Imaging Corporation (now GeoEye). The GeoEye/OrbView - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

QuickBird/WorldView - Orbital Pushbroom Use this model for QuickBird or WorldView images in which RPC data is not available. QuickBird produces sub-meter resolution panchromatic and multispectral imagery. WorldView-1 produces 0.5 meter resolution panchromatic imagery. Both satellite systems are a development of DigitalGlobe. The QuickBird/WorldView - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

SPOT5 - Orbital Pushbroom Use this model for SPOT5 sensor data. SPOT5 carries two HRVIR instruments, an HRS (High Resolution Stereoscopic) instrument, and a VEGETATION 2 instrument onboard. The SPOT5 - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

SPOT6 - Orbital Pushbroom Use this model for SPOT 6 sensor data.

SPOT7 - Orbital Pushbroom Use this model for SPOT 7 sensor data.

If you want to orthorectify a SPOT-5 DIMAP image data set, the input file you select should recognize the SPOT DIMAP raster DLL, then the DLL is able to use the ephemeris information and does not import the image first.

THEOS1 - Orbital Pushbroom Use this model for THEOS sensor data. The THailand Earth Observation System is fully operated by the Geo-Informatics and Space Technology Development Agency (GISTDA), Ministry of Science and Technology, Thailand. Sensor resolution is 2 meters in panchromatic and 15 meters in multispectral images. The THEOS1 - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

GOKTURK-1 - Orbital Pushbroom Use this model for GOKTURK-1 sensor data.

KazEOSat-1 - Orbital Pushbroom Use this model for KazEOSat-1 sensor data.

KazEOSat-2 - Orbital Pushbroom Use this model for KazEOSat-2 sensor data.

VNREDSat-1 - Orbital Pushbroom Use this model for VNREDSat-1 sensor data. VNREDSat-1 (short for Vietnam Natural Resources, Environment and Disaster Monitoring Satellite)[2] is the first optical Earth Observing satellite of Vietnam; its primary mission is to monitor and study the effects of climate change, predict and take measures to prevent natural disasters, and optimise the management of Vietnam's natural resources.

IKONOS Use this model for IKONOS sensor imagery that includes RPC data. The IKONOS sensor, owned by GeoEye, has collected panchromatic images with 82-centimeter resolution and multispectral imagery with 4-meter resolution. The IKONOS model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The IKONOS RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

To orthorectify IKONOS multispectral products separated into one band per file, see Rectify or Orthorectify IKONOS Data.

NITF RPC Use this model for NITF (National Imagery Transmission Format) data that includes RPC data. This model requires the use of rational polynomial coefficients, which are embedded in the *.ntf file, to describe the relationship between the image and the Earth's surface at the time of image capture. The NITF RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

QuickBird RPC Use this model for QuickBird imagery that includes RPC data. This satellite system is a development of DigitalGlobe. This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture.The QuickBird RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

ORBIMAGE RPC Use this model for ORBIMAGE imagery that includes RPC data. ORBIMAGE and Space Imaging combined to form the company named GeoEye. This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The ORBIMAGE RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

CARTOSAT RPC Use this model for CARTOSAT imagery that includes RPC data. The CARTOSAT satellites are built by ISRO (Indian Space Research Organization). This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The CARTOSAT RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

RESOURCESAT RPC Use this model for RESOURCESAT imagery that includes RPC data. RESOURCESAT, also known as IRS P6, was built by ISRO (Indian Space Research Organization). The RESOURCESAT model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The RESOURCESAT RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

IND High Res RPC Use this model for ISRO (Indian Space Research Organization) satellite systems imagery that includes RPC data. This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The IND High Res RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

WorldView RPC Use this model for WorldView imagery including RPC data. This satellite system is a development of DigitalGlobe. This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The WorldView RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

ALOS RPC Use this model for ALOS imagery that includes RPC data. This model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

GeoEye RPC Use this model for GeoEye or OrbView imagery that includes RPC data. This model is for data collected by GeoEye-1 satellite, developed by GeoEye, a company formed through the combination of ORBIMAGE and Space Imaging, as well as data collected by OrbView-3 satellite, built for Orbital Imaging Corporation (now GeoEye). The GeoEye model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The GeoEye RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

KOMPSAT RPC Use this model for KOMPSAT imagery that includes RPC data. The KOMPSAT satellite systems are developed by Korea Aerospace Research Institute. The KOMPSAT model requires the use of rational polynomial coefficients to describe the relationship between the image and the Earth's surface at the time of image capture. The KOMPSAT RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

DEIMOS RPC Use this model for DEIMOS imagery that includes RPC data. DEIMOS-1 satellite is operated by Deimos Space of Spain. DEIMOS-1 is part of the international constellation DMC (Disaster Monitoring Constellation), composed of satellites from the UK, China, Nigeria, Spain, and Algeria.The DEIMOS RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

RAPIDEYE RPC Use this model for RapidEye imagery that includes RPC data. RapidEye is a constellation of five satellite sensors operated by the German company RapidEye AG. The RapidEye RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

SPOT6 RPC Use this model for SPOT 6 imagery that includes RPC data.

SPOT7 RPC Use this model for SPOT 7 imagery that includes RPC data.

TH-01 RPC Use this model for TH-01 imagery that includes RPC data. TH-01 is a Chinese satellite launched in August 2010. The TH-01 RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Pleiades RPC Use this model for Pleiades imagery that includes RPC data. The Pleiades RPC Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Pleiades - Orbital Pushbroom Use this model for Pleiades sensor data. Pleiades carries two HRVIR instruments, an HRS (High Resolution Stereoscopic) instrument, and a VEGETATION 2 instrument onboard. The Pleiades - Orbital Pushbroom Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

SkySat RPCUse this model for SkySat imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *_rpc.txt.

GOKTURK/RASAT RPCUse this model for GOKTURK or RASAT imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *rpc.txt.

KazEOSat-1 RPCUse this model for KazEOSat-1 imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is RPC.XML.

Planet Labs RPCUse this model for Planet Labs imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *_rpc.txt.

UK-DMC SLIM-6-22 RPCUse this model for UK-DMC SLIM-6-22 imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *.rpc.

DMC-3 RPCUse this model for DMC-3 imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *rpc.txt.

Perusat RPCUse this model for Perusat-1 imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of rpc*.xml.

EROS RPCUse this model for EROS imagery that comes with the Rational Polynomial Coefficients (RPC) file which has the information to transfer object space coordinates to image space coordinates. The RPC file name is in a pattern of *.rpc.

ZY-3 RPC Use this model for ZY-3 imagery that comes with Rational Polynomial Coefficient (RPC) files for performing image to ground transformation. The RPC filename follows the pattern [imagename]_rpc.txt. The ZY-3 Surveying and Mapping satellite is a Chinese satellite which was launched in Jan. 2012.

IRS Use this model for ISRO (Indian Space Research Organization) IRS-1C and IRS-1D satellite systems imagery. The data product should be imported using the IRS-1C/1D (Super Structured Format) dialog. The IRS Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Landsat The Landsat model allows orthorectification of Landsat data, such as TM and MSS, which have multiple perspective centers. The Landsat Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

SAR (Synthetic Aperture Radar)Use this model for data collected from a Synthetic Aperture Radar (SAR) satellite system. The SAR (Synthetic Aperture Radar) Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Polynomial Polynomial geometric model uses polynomial coefficients to map between image spaces. The order of the polynomial may be from one up to five with no enforced upper limit. The Polynomial Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

To perform an Affine transform using GCPs, use a 1st order Polynomial transform. Affine is the same transformation as a 1st order Polynomial transform.

Projective Transform Projective Transform model provides a more powerful modeling capability for multi-perspective satellite images such as Landsat, SPOT, Camera and QuickBird, which may not be satisfied with simple linear modeling. The Projective Transform Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

Reproject This option is available only when the image has projection information. An input image already projected to a map space can be reprojected to another map system. The projection model is actually a polynomial approximation using a grid of regularly spaced points. The Reprojection Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

For information about reprojection without using polynomial approximation or with multiple input files, refer to Reproject Images.

Rubber Sheeting Uses piecewise polynomials for image rectification. The Rubber Sheet Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs. This model should be used only when:

- Geometric distortion is severe
- GCPs are abundant
- No other geometric model is applicable

Spot SPOT model allows orthorectification of SPOT panchromatic or multispectral (XS) data, which use pushbroom as their sensor model. Even though SPOT 1B (systematically corrected) format is supported, it is more efficient to use SPOT 1A (raw) format for this model. The Spot Model Properties dialog opens after determining the GCP collection method, or after specifying the model name in methods without GCPs.

OK Accept the selected Geometric Model and close this dialog.

Cancel Cancel the geometric correction process and close this dialog.

Help Open this Help document.

When opened from IMAGINE AutoSync, there is no Projection Tab on each of the above Model Properties dialogs. You need to set the Projection using Projection tab of Project Properties dialog in AutoSync Workstation or Projection tab of IMAGINE AutoSync Georeferencing Wizard.

For information about supported sensor models, see Sensor Model Selection Guide - IMAGINE and Optical Satellite Data in Producer Field Guide.

For more information about the rectification process, see Raster Image Rectification.