Data Correction

Producer Field Guide

HGD_Product
Producer Field Guide
HGD_Portfolio_Suite
Producer

There are several types of errors that can be manifested in remotely sensed data. Among these are line dropout and striping. These errors can be corrected to an extent in GIS by radiometric and geometric correction functions.

Radiometric errors are usually already corrected in data from Landsat or SPOT.

See Enhancement for more information on radiometric and geometric correction.

Line Dropout

Line dropout occurs when a detector either completely fails to function or becomes temporarily saturated during a scan (like the effect of a camera flash on a human retina). The result is a line or partial line of data with higher data file values, creating a horizontal streak until the detector recovers, if it recovers.

Line dropout is usually corrected by replacing the bad line with a line of estimated data file values. The estimated line is based on the lines above and below it.

SHARED Tip You can correct line dropout using the 5 × 5 Median Filter from Radar Speckle Suppression function. The Convolution and Focal Analysis functions also correct for line dropout.

Striping

Striping or banding occurs if a detector goes out of adjustment—that is, it provides readings consistently greater than or less than the other detectors for the same band over the same ground cover.

SHARED Tip Use ERDAS IMAGINE Image Interpretation functions or Spatial Modeler for implementing algorithms to eliminate striping. Use Spatial Modeler editing capabilities to adapt the algorithms to best address the data.