Import Meta Data

Choosing Import Orbit from an image node will open a metadata import dialog. Barista supports the satellites SPOT 5, ALOS PRISM and QuickBird for use with the Pushbroom scanner model. The Pushbroom scanner model can only be used with the raw datasets provided by the satellite vendors. Select first one of these three satellites. The supported processing levels are:

• SPOT 5
  • Level 1A - Radiometric corrected
• ALOS PRISM
  • Level 1A - Raw data
  • Level 1B1 - Radiometric corrected
• QuickBird
  • Basic Imagery

After the satellite has been chosen click on Select File to open the metadata file for the selected satellite. If the original files have not been renamed select one of following files:

• SPOT 5
  • METADATA.DIM
• ALOS PRISM
  • IMG-'CCD'-'scene id'-'product id'
• QuickBird
  • MUL_README.txt
  • PAN_README.txt

Import Meta Data Dialog

When an appropriate file has been selected the appropriate parameters are determined in a preprocessing step. Barista will also check if matching orbit paths, orbit attitudes, camera mountings or cameras may already exist in the project. If this is the case, Barista will automatically select the existing parameters and skip the parameter from the metadata file. There is no need to change the pre-selection! However, selecting Use from file under Choose existing parameters will use the parameters read from the metadata file.

If known, enter some additional information under Enter Information. These information are used to improve the direct geo-referencing. These parameters are not essential when ground control points (GCPs) are used for bias correction.

Barista determines parameters to approximate the orbit path and the orbit attitude while reading the selected metadata file. Both orbit path and attitude are approximated by cubical splines. Section Determine Orbit accuracy defines the accuracy threshold Barista has to achieve when determining appropriate spline parameters. The thresholds unit is sigma a priori. That means, a value of 0.5 indicates that the accuracy of the approximation is twice as good as the accuracy of the given orbit parameters imported from a metadata file. Generally, there is no need to change these settings!

The threshold for the accuracy can be changed either before the metadata are imported or afterwards. When changed afterwards use Recompute Orbit to trigger a new computation. See achieved accuracy for the actual achieved accuracy during the parameter determination. Note: The accuracy of the orbit parameters can only be changed when the parameters imported form the selected file are used.

Press Import to finally load the read metadata into the Barista project. After import, a PushbroomScanner node will be created and added to the assigned image. Depending on the selection under Choose existing parameters, additional nodes for the satellite camera, the satellite camera mounting, the satellite orbit path and orbit attitudes are created.

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