dap4/d4lib/src/main/java/dap4/dap4lib/AbstractDSP.java
protected boolean suppress(String attrname)
    {
        if(attrname.startsWith("_Coord")) return true;
        if(attrname.equals("_Unsigned"))
            return true;
        return false;
    }
protected boolean suppress(String attrname)
    {
        if(attrname.startsWith("_Coord")) return true;
        if(attrname.equals("_Unsigned"))
            return true;
        return false;
    }
Some attributes that are added by the NetcdfDataset
need to be kept out of the DMR. This function
defines that set.

@param attrname A non-escaped attribute name to be tested for suppression
@return true if the attribute should be suppressed, false otherwise.