Geografic-Information-System/imagery/i.modis.qc/mod13A2c.c

/* mod13A2 Aerosol quantity Flags 1Km bits[6-7]
 * 00 -> class 0: Climatology
 * 01 -> class 1: Low
 * 10 -> class 2: Average
 * 11 -> class 3: High
 */  

#include <grass/raster.h>

CELL mod13A2c (CELL pixel) 
{
    CELL qctemp;

    pixel >>= 6;		/*bits [6-7] become [0-1] */
    qctemp = pixel & 0x03;
    
    return qctemp;
}