Available with Advanced license.
To create an ortho mapping workspace for processing RedEdge and Altum images, you need two types of information about your imagery: the geolocation information and the 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. The camera type is used to compute a camera model based on the specifications of the camera.
Workflow data requirements
The drone workflow for processing RedEdge or Altum imagery requires two types of data:
- 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—This provides an initial height reference for computing the block adjustment. The global DEM is used by default.
Create an ortho mapping workspace
To create an ortho mapping workspace using RedEdge or Altum drone imagery, complete the following steps:
- On the Imagery tab, click New Workspace.
- On the Workspace Configuration page, type a name for your workspace.
- From the Workspace Type drop-down menu, choose Drone.
- From the Basemap drop-down menu, choose a basemap as a backdrop for your image collection.
- Click Next.
- In the Image Collection pane, choose RedEdge or Altum from the Sensor Type drop-down menu.
- Click the browse button, browse to a folder, and load the imagery for the project.
The Geolocation and Camera Model parameters are automatically populated from the metadata in the EXIF headers.
- If the images in your collection do not contain an EXIF header, provide a Geolocation GPS text file, such as a comma-separated values (CSV) file, that includes values for the Image Name, Latitude, Longitude, and Altitude fields, and optionally, the Omega, Phi, and Kappa fields. 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 height above a vertical datum or height relative to the 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.
- Spatial Reference is automatically populated with the GPS location from your data. Optionally, click the spatial reference button and 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.
- Click Next.
- On the Data Loader tab, you can refine the output drone workspace and perform optional calibration of your imagery.
- 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.
- Choose a Processing Template.
- Choose a Radiometric Quantity Type.
To perform quantitative analysis of your multispectral imagery or derive image indices, choose Reflectance. Digital Number and Radiance are suitable options for image display.
- If the Radiometric Quantity Type is set to Reflectance, and your image collection includes an image of the surface reflectance calibration panel, check the Calibrate using surface reflectance panel check box. A table appears listing the bands, along with a dialog box for computing the reflectance factor for each band.
- Click the Calculate button to open the Calculate panel reflectance factor window.
- Click the browse button and browse to and select the image of your surface reflectance panel.
- Click the Sketch area for calibration button and click in the reflectance calibration panel to define the panel area in the image.
To determine the reflectance ratio for Average Panel Reflectance, visit the MicaSense panel reflectance page and use the email link to obtain the reflectance value for your panel. Make sure to provide the serial number for your panel, which is listed with the QR code on the reflectance panel.
- Enter the provided reflectance ratio value in the Average Panel Reflectance text box and click OK. Repeat this for the remaining bands.
- Optionally, edit the Band Combination parameters to reorder the band combination from the default order.
- Elevation Source
- Click Finish to create the workspace.
When the ortho mapping workspace is created, the image collection is loaded in the workspace and displayed on the map. You are now ready to perform block adjustment and generate ortho products.