The OrthoEngine GCP Collection, Tie Point Collection and Residual windows each have an RPC Adjustment Order list. The RPC adjustment order is the order of the polynomial used to refine the RPC model. The RPC adjustment order is 0, 1 or 2. An additional option, Automatic/mixed, will assign an RPC adjustment order to the OrthoEngine photo based on the sensor.
The RPC adjustment order is photo-specific; therefore, an OrthoEngine project file can have a different adjustment order for each photo. You may want to use different adjustment orders depending on the sensor, the number of GCPs/TPs collected, and the accuracy of the GCPs/TPs.
When the RPC math model is refined with OrthoEngine , the adjustment order for each photo can be changed if there is an insufficient number of GCPs/TPs for that order. The order will be adjusted such that the highest order will be used based on the number of GCPs/TPs.
The RPC adjustment order for a sensor is defined by the entry of the file-level AdjustmentOrder metadata tag. If this tag does not exist, the RPC adjustment order is defaulted to a value of 1. The following GDB-supported sensors have a metadata adjustment order of zero: Geoeye, Ikonos, WorldView 1, and WorldView 2.
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