Create an ortho mapping workspace for drone imagery

Available with Advanced license.

To create an ortho mapping workspace for processing your drone images, you will need two types of information about your drone imagery: the geolocation information and the camera information. This information is commonly stored as metadata in the image files, typically in the EXIF header, and includes latitude, longitude, altitude, and camera type. The camera type is used to compute a camera model based on the specifications of the camera.

Workflow data requirements

• Geolocation and Camera Model-This information is commonly stored as metadata in the image files, typically in the EXIF header, and includes latitude, longitude, altitude, and camera type.
• DEM- Provides an initial height reference for computing the block adjustment. The global DEM is used by default. For relatively flat terrain, you can specify an average elevation or Z value.

To create an ortho mapping workspace from drone imagery, complete the following steps:

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 Drone.
4. Use the Basemap drop-down list to choose the basemap you want to use as a backdrop for your image collection. You can also import and use an existing image collection for your workspace.
5. Click Next.
6. On the Image Collection page, choose your sensor type using the Sensor Type drop-down menu. The drone ortho mapping workspace supports the generic sensor type, which is a single-sensor drone system, with numerous camera models. Alternatively, choose RedEdge or Altum for one of the supported multisensor systems. For more information on setting up a workspace for these sensor types, see Create an Ortho Mapping workspace for RedEdge or Altum sensors.
7. Click the Add button to browse to a folder and load the drone imagery for this project.

   If your imagery has the proper metadata in its EXIF headers, the Geolocation and Camera Model parameters are automatically populated.

8. If the images in your collection do not contain an EXIF header, you will need to provide a Geolocation GPS text file, such as a comma-separated value (CSV) file, which includes values for the fields: Image Name, Latitude, Longitude, and Altitude, and optionally, Omega, Phi, and Kappa. The geolocation file should have been provided by your vendor with the drone imagery. Click the import button to browse to the GPS text file.
Z values are typically recorded as heights above a vertical datum or heights relative to the drone takeoff point. To edit the altitude reference of your image collection, click the edit button next to the Geolocation information. For Z Value Type, select Flight Height if your drone reports heights relative to the takeoff point, or Altitude for heights relative to a vertical datum. Click OK to save the settings on the Edit Geolocation Reference page.
9. Spatial Reference is automatically populated with the GPS location from your data. Click the spatial reference button to optionally select a different map reference system and vertical coordinate system. The coordinate systems of the workspace will be used in the map, resulting orthomosaic, and DEM.
10. If the camera type is missing from the EXIF header information, click the properties button to open the Edit Camera Parameters page and select your Camera Maker and Camera Model. Once you select the camera make and model, the wizard will complete the form based on the extensive database of supported cameras, and compute the camera model, also known as the interior orientation. If your camera is not supported, you can enter the camera information on the Edit Camera Parameters page and save it. The camera parameters setting will be used to compute the camera model.

    Note:

    Only values for Focal length (mm) and Pixel Size on the Sensor (in mm) are required to compute the camera model. These values can often be found in the image properties, although in some cases, they are missing. In this case, the Pixel Size on the Sensor will be estimated automatically for the 35 mm equivalent focal length for supported camera models using the equations below:

    Pixel Size = CCD Diagonal / Image Diagonal(in pixels)

    where

    CCD Diagonal = 2 * (Focal Length * Tan(FOV/2))

    If this value is not automatically calculated, click the Pixel Size on the Sensor button and choose Field of view (FOV), 35 mm equivalent focal length, or Dimension in the Sensor Specification drop-down menu. Enter the corresponding specifications for your camera model and click OK. The value for Pixel Size on the Sensor should now be populated.

    1. Choose the correct Camera File with the camera model information. This can be a .cam file or a .csv file. If neither is available, you can manually enter the camera parameters on this page.
    2. Click the Back button to return to the Image Collection page.
11. Optionally, click the Data Loader tab to further refine your output drone workspace.
    1. 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.
       • If you do not have access to the internet or a DEM, choose the Constant Elevation option from the drop-down menu and enter an elevation value. This is only used to provide an initial estimate of the flight height for each image.
    2. Edit the Band Combination parameters if you want to reorder the band combination from the default order.
12. 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.

Drone imagery tutorial

For a guided tutorial on the full drone imagery workflow, see Create Drone Imagery Products.