ui/src/main/java/ucar/nc2/ui/coverage2/CoverageRenderer.java
public DataState setCoverage(CoverageCollection coverageDataset, Coverage grid) {
    this.dataState = new DataState(coverageDataset, grid);
    this.lastGrid = null;
    isNewField = true;
    return this.dataState;
  }
public DataState setCoverage(CoverageCollection coverageDataset, Coverage grid) {
    this.dataState = new DataState(coverageDataset, grid);
    this.lastGrid = null;
    isNewField = true;
    return this.dataState;
  }
/* set the Grid