ui/src/main/java/ucar/nc2/ui/gis/SpatialGrid.java
public void clear() {
   for (int y=0; y<countY; y++)
     for (int x=0; x<countX; x++)
       gridArray[y][x].used = false;
  }
public void clear() {
   for (int y=0; y<countY; y++)
     for (int x=0; x<countX; x++)
       gridArray[y][x].used = false;
  }
clear all the grid cells