Selection of this option brings up a heading GRID CONFIGURATION in the right-hand panel followed by the name of the file being edited and the name of the next interim save file ( see {TOP.FILE}INTERIMSAVE ). Below these are three grid colour panels labelled FIRST, SECOND and MODIFY. Initially, these show the respective default colours cyan, red and yellow. Any of the three colours in use can be changed by placing the cursor on the respective colour panel and clicking the mouse until the desired colour comes up.
Normal practice is to display the whole grid in the FIRST colour. This is ensured by making the value SECONDARY COLOUR INDEX (below the colour panels) greater than the number of nodes in the grid being edited. To reset the value of the SECONDARY COLOUR INDEX, place the cursor on the current value displayed and click the mouse, then enter the new value via the keyboard.
Use of two grid colours (FIRST and SECOND) is convenient when joining two grids initially independent of one another. The two grid files must first be input to the program PREJOIN, which renumbers the indices of the nodes of the second grid to follow consecutively after the indices of the first grid and outputs the two grids in a single grid file. This combined file can be read in by the Editor, to which it appears as a single grid, although there are as yet no connections between the two component parts. If the value of the SECONDARY COLOUR INDEX is set to be 1 greater than the number of nodes in the first component grid, the two parts of the new grid will be displayed in the FIRST and SECOND colours. This is most helpful in the subsequent MERGE operations needed to join the two grids (see further remarks under {TOP.CONFIG}GRIDMERGE below).
When any part of the grid is edited, the revisions will be displayed in the MODIFY colour until the next screen refresh (by REFRESH or by rewindowing).
When any required changes have been made in the grid configuration panel, move the cursor on to ACCEPT at the bottom of the panel and click the mouse.