earth-observation-for-journ.../true-color-image/02b Timeseries.ipynb

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6.8 KiB
Text

{
"cells": [
{
"cell_type": "code",
"execution_count": 1,
"metadata": {},
"outputs": [],
"source": [
"from pathlib import Path\n",
"from multiprocessing import Pool\n",
"import geopandas as gpd\n",
"from sentinel_helpers import scihub_band_paths"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {},
"outputs": [],
"source": [
"base_path = Path('input/tempelhofer_feld/')\n",
"input_files = list(base_path.glob('*.zip'))\n",
"area_of_interest = gpd.read_file(base_path / 'tempelhofer_feld.geojson')\n",
"ndvi_path = base_path / 'ndvi'"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [],
"source": [
"import rasterio as r\n",
"import rasterio.mask\n",
"import rasterio.plot as rplt\n",
"import numpy as np\n",
"from sentinel_helpers import scihub_normalize_range\n",
"from zipfile import BadZipFile"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [],
"source": [
"def calculate_ndvi(raster_file):\n",
" global area_of_interest\n",
" \n",
" try:\n",
" b04_path, b08_path = scihub_band_paths(raster_file, ['B04', 'B08'], '10m')\n",
" except BadZipFile:\n",
" print(f'Problem reading {raster_file}, skipping it')\n",
" return\n",
"\n",
" with r.open(b04_path, 'r') as b04, r.open(b08_path, 'r') as b08:\n",
" # we want to only write the bare minimum data necessary to disk\n",
" out_meta = b04.meta.copy()\n",
"\n",
" # we reproject the geojson file we fetched above and convert it so that rasterio\n",
" # can use it as a mask\n",
" mask = area_of_interest.to_crs(out_meta['crs']).iloc[0].geometry\n",
" miny, minx, maxy, maxx = mask.bounds\n",
"\n",
" # update the dimensions and save as geotiff, not jp2\n",
" out_meta.update({\n",
" 'width': maxx - minx,\n",
" 'height': maxy - miny,\n",
" 'driver': 'GTiff',\n",
" 'dtype': 'float32'\n",
" }) \n",
" out_name = Path(b04_path).name.replace('B04', 'NDVI').replace('.jp2', '.tif')\n",
"\n",
" ! mkdir -p {ndvi_path}\n",
" with r.open(ndvi_path / out_name, 'w+', **out_meta) as dst:\n",
" # we take only the part out of our source raster that we actually need\n",
" # crop=True clips off the borders\n",
" b04, transform_b04 = rasterio.mask.mask(b04, shapes=[mask], crop=True)\n",
" b08, _ = rasterio.mask.mask(b08, shapes=[mask], crop=True) # we ignore the returned transform because it's identical to the previous one\n",
"\n",
" b04 = scihub_normalize_range(b04).astype('f4') # <- f4 = float32\n",
" b08 = scihub_normalize_range(b08).astype('f4')\n",
"\n",
" # uncomment the following line to see if your masked shape looks correct\n",
" #rplt.show(b04, transform=transform_b04)\n",
" #rplt.show(b08, transform=transform_b04)\n",
"\n",
" # we want to be able to ignore divide by zero errors so the formula is nicer to write\n",
" np.seterr(divide='ignore', invalid='ignore')\n",
" ndvi = (b08 - b04) / (b08 + b04)\n",
"\n",
" # uncomment the following line to see if we calculated the index correctly\n",
" # rplt.show(ndvi, transform=transform_b04)\n",
"\n",
" dst.write(ndvi)"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [],
"source": [
"from tqdm.notebook import tqdm"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"data": {
"application/vnd.jupyter.widget-view+json": {
"model_id": "d6bb63ba04f94679ab26c02235782b3c",
"version_major": 2,
"version_minor": 0
},
"text/plain": [
"HBox(children=(HTML(value=''), FloatProgress(value=0.0, max=40.0), HTML(value='')))"
]
},
"metadata": {},
"output_type": "display_data"
},
{
"name": "stdout",
"output_type": "stream",
"text": [
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190603T101031_N0212_R022_T33UUU_20190603T114652.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190404T101031_N0211_R022_T32UQD_20190404T174806.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190216T102111_N0211_R065_T33UUU_20190216T130428.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2B_MSIL2A_20190419T101029_N0211_R022_T33UUU_20190419T132322.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190407T102021_N0211_R065_T33UUU_20190407T134109.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2B_MSIL2A_20190512T102029_N0212_R065_T33UUU_20190512T134103.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190613T101031_N0212_R022_T33UUU_20190614T125329.zip, skipping itProblem reading input/tempelhofer_feld/S2A_MSIL2A_20190424T101031_N0211_R022_T32UQD_20190424T162325.zip, skipping it\n",
"\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190822T101031_N0213_R022_T32UQD_20190822T143621.zip, skipping it\n",
"Problem reading input/tempelhofer_feld/S2A_MSIL2A_20190623T101031_N0212_R022_T33UUU_20190623T132509.zip, skipping it\n",
"\n",
"CPU times: user 179 ms, sys: 154 ms, total: 333 ms\n",
"Wall time: 23.7 s\n"
]
}
],
"source": [
"%%time\n",
"\n",
"pool = Pool()\n",
"\n",
"for _ in tqdm(pool.imap_unordered(calculate_ndvi, input_files), total=len(input_files)):\n",
" # this loop is only here so we can get the progress bar\n",
" pass"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"How many files could we process?"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"31\n"
]
}
],
"source": [
"! ls -l {ndvi_path} | wc -l"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.8.6"
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"nbformat": 4,
"nbformat_minor": 4
}