Create an ortho mapping workspace for digital aerial imagery

Available with Advanced license.

Creating an ortho mapping workspace computes the interior and exterior orientation for one or more images in your project. If you have imagery from a camera system with metadata that provides accurate interior and exterior orientation information, you can use this workflow. Computing the photogrammetric solution for an aerial image is determined by its exterior orientation, which represents a transformation from the ground to the camera, and its interior orientation, which represents a transformation from camera to image.

Note:

Most aerial camera systems provide imaging platform data in the form of longitude, latitude, and flying height (x,y,z) using airborne GPS data, and orientation data in the form of Omega, Phi, and Kappa using an inertial measurement unit (IMU). This data is provided for each image collected by the airborne sensor, and stored either in the header of the image or in a separate metadata file.

The Ortho Mapping Workspace wizard guides you through the creation of an ortho mapping workspace for your digital aerial imagery, such as Applanix, ISAT, and Match-AT raster types. For aerial imagery from generic digital mapping camera systems such as UltraCam, Leica DMS, Intergraph DMC, or similar, you need to create a camera table that defines the camera model and resulting interior orientation, and frame table that defines the exterior orientation of the images. These tables are also created using the Ortho Mapping Workspace wizard, as described in the workflow below.

Workflow data requirements

To create a workspace for digital aerial imagery, you'll need the following data:

• Camera table—Includes measurements of sensor characteristics, such as focal length, size and shape of the imaging plane, pixel size, and lens distortion parameters. In photogrammetry, the measurement of these parameters is called interior orientation (IO), and they are encapsulated in a camera model file. High-precision aerial mapping cameras are analyzed to provide camera calibration information in a report used to compute a camera model. Other consumer-grade cameras are calibrated by the camera manufacturer, those operating the cameras, or they can be calibrated during the adjustment processes. See Build Frames and Camera Tables tool, Frames table schema and Cameras table schema for more information.
• Frames table—Describes the position of the sensor at the instant of image capture in coordinates such as latitude, longitude, and height (x,y,z), as well as the attitude of the sensor, expressed as Omega, Phi, and Kappa (pitch, roll, heading). The measurement of these parameters is referred to as exterior orientation (EO), and should be provided with the imagery. For information on formatting this data, see Frames table schema.
• DEM—Provides an initial height reference for computing the block adjustment. The global DEM is used by default. For relatively flat terrain, you may specify an average elevation or z-value.

Create an ortho mapping workspace

You can create an aerial imagery workspace for your project using the workflow wizard.

1. On the Imagery tab, click New Workspace.
2. On the Workspace Configuration page, type a name for your workspace.
3. Use the Workspace Type drop-down arrow to choose Aerial - Digital.
4. Click Next.
5. On the Image Collection page, choose Generic Frame Camera as the Sensor Type.
   • If you have Match-AT, ISAT, or Applanix raster type data, choose the corresponding Sensor Type .
6. Specify the Exterior Orientation File / Esri Frames Table. This table enables specification of parameters that compute the exterior orientation of your imagery. It is a .csv file generated by the Build Frame and Camera Tables tool. If you do not have a frames table, you can select your .csv metadata file associated with your image collection.

   If you input an Exterior Orientation File that is not an Esri Frames Table file, the Frames page will open for you to input field mapping information. The Frames page is the same page incorporated in the Build Frame and Camera Tables tool.

7. The Spatial Reference parameter will be automatically set by the spatial reference of the perspective points defined in the Esri Frames Table. If the Spatial Reference parameter is not specified, click the Spatial Reference button to set the spatial reference to be the same coordinate system as the perspective points.
8. Specify the Cameras table file. This is the .csv file that contains the camera configuration information, generated using the Build Frame and Camera Tables tool.

   If you Add a camera , or Import a camera file that does not conform to the camera table schema generated by the Build Frame and Camera Tables tool, the Add New Camera page will open for you to enter the camera information. The Calibration tab on the Add New Camera page is where you enter the camera information, usually available from the manufacturer.

   Use the Distortion tab to enter the camera distortion information, if available. This type of information is often available in the camera calibration report when your mapping camera is calibrated.

   You can use the Export button on the Source Data Properties tab to store the camera calibration parameters as an Esri Cameras Table for future use.

9. Optionally, click the Data Loader Options tab on the Image Collection page to further refine your output workspace.
   1. Creating an ortho mapping workspace from aerial imagery requires elevation data. The DEM parameter wizard provides an elevation service with a 90-meter resolution by default, however, this will only allow for coarse orthorectification. You can use a different DEM service or file by navigating to it. Choose your Elevation Source.
      • If you have access to the internet, use the default elevation service for the DEM parameter, and Average Elevation from DEM for the Elevation Source option.
      • If you do not have access to the internet, provide a DEM file covering the project area, and choose Average Elevation for the Elevation Source option.
   2. Check the Estimate Statistics check box to estimate the statistics for your output workspace.
   3. Edit the Band Combination parameters to reorder the band combination from the default order.
   4. Choose either of the Pre-processing options to Calculate Statistics or Build Pyramids on your data before you create your workspace.
10. Click Finish to create the workspace.

When the ortho mapping workspace is created, the image collection will be loaded in the workspace and displayed on the map. You are now ready to perform adjustments and generate ortho products.