In many cases the automatic sequence of steps provided by ECHMENU's main menu defaults will be enough to complete the reduction. In some cases, however, it may be necessary to restart the reduction at a particular stage, maybe using a different raw image, different degree of polynomial etc.
ECHOMOP allows the selection of any valid step of a reduction at any stage. If the step requested needs results from steps which have not yet been performed then the user will be informed of this and the default next step will be set back to the step which generates the required information.
If a single step task is invoked before all its input requirements are available (e.g. order tracing before order location) then the task will abort with a message indicating which task needs to be run in order to provide the necessary pre-requisites.
Martin Clayton