\n",
"\n",
"| Bit number | \n",
"Parameter Name | \n",
"Bit combination | \n",
"Interpretation | \n",
"
\n",
"\n",
"| 0 | \n",
"MODLAND_QC bits | \n",
"0 | \n",
"Good quality (main algorithm with or without saturation) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"1 | \n",
"Other Quality (back-up algorithm or fill values) | \n",
"
\n",
"\n",
"| 1 | \n",
"Sensor | \n",
"0 | \n",
"Terra | \n",
"
\n",
"\n",
" | \n",
" | \n",
"1 | \n",
"Aqua | \n",
"
\n",
"\n",
"| 2 | \n",
"DeadDetector | \n",
"0 | \n",
"Detectors apparently fine for up to 50% of channels | \n",
"
\n",
"\n",
" | \n",
" | \n",
"1 | \n",
"Dead detectors caused >50% adjacent detector retrieval | \n",
"
\n",
"\n",
"| 3-4 | \n",
"CloudState | \n",
"00 | \n",
"Significant clouds NOT present (clear) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"01 | \n",
"Significant clouds WERE present | \n",
"
\n",
"\n",
" | \n",
" | \n",
"10 | \n",
"Mixed cloud present on pixel | \n",
"
\n",
"\n",
" | \n",
" | \n",
"11 | \n",
"Cloud state not defined (assumed clear) | \n",
"
\n",
"\n",
"| 5-7 | \n",
"CF_QC | \n",
"000 | \n",
"Main (RT) method used (best result possible (no saturation)) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"001 | \n",
"Main (RT) method used with saturation. (usable) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"010 | \n",
"Main (RT) method failed due to bad geometry (empirical algorithm used) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"010 | \n",
"Main (RT) method failed due to problems other than geometry (empirical algorithm used) | \n",
"
\n",
"\n",
" | \n",
" | \n",
"010 | \n",
"Pixel not produced at all. | \n",
"
\n",
"
\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"So, the MODIS LAI QA information is contained in one byte (8 bits), which encodes data about five different categories of QA information.\n",
"\n",
"When using such data, we need to make choices about what quality of data we are willing to accept.\n",
"\n",
"For the moment, you can ignore this piece of code below. We will learn of such things later, but here we read in some data into a variable `qa`, and diaplay those data:"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"data": {
"text/plain": [
"