Mean_NDVI / app.py
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Add Zonalstats for Buffer
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import os
import ee
import geemap
import json
import geopandas as gpd
import streamlit as st
import pandas as pd
from fastkml import kml
import geojson
from shapely.geometry import Polygon, MultiPolygon, shape, Point
ee_credentials = os.environ.get("EE")
os.makedirs(os.path.expanduser("~/.config/earthengine/"), exist_ok=True)
with open(os.path.expanduser("~/.config/earthengine/credentials"), "w") as f:
f.write(ee_credentials)
ee.Initialize()
def convert_3d_to_2d(geometry):
"""
Recursively convert any 3D coordinates in a geometry to 2D.
"""
if geometry.is_empty:
return geometry
if geometry.geom_type == 'Polygon':
return geojson.Polygon([[(x, y) for x, y, *_ in ring] for ring in geometry.coordinates])
elif geometry.geom_type == 'MultiPolygon':
return geojson.MultiPolygon([
[[(x, y) for x, y, *_ in ring] for ring in poly]
for poly in geometry.coordinates
])
elif geometry.geom_type == 'LineString':
return geojson.LineString([(x, y) for x, y, *_ in geometry.coordinates])
elif geometry.geom_type == 'MultiLineString':
return geojson.MultiLineString([
[(x, y) for x, y, *_ in line]
for line in geometry.coordinates
])
elif geometry.geom_type == 'Point':
x, y, *_ = geometry.coordinates
return geojson.Point((x, y))
elif geometry.geom_type == 'MultiPoint':
return geojson.MultiPoint([(x, y) for x, y, *_ in geometry.coordinates])
return geometry # Return unchanged if not a supported geometry type
def convert_to_2d_geometry(geom): #Handles Polygon Only
if geom is None:
return None
elif geom.has_z:
# Extract exterior coordinates and convert to 2D
exterior_coords = geom.exterior.coords[:] # Get all coordinates of the exterior ring
exterior_coords_2d = [(x, y) for x, y, *_ in exterior_coords] # Keep only the x and y coordinates, ignoring z
# Handle interior rings (holes) if any
interior_coords_2d = []
for interior in geom.interiors:
interior_coords = interior.coords[:]
interior_coords_2d.append([(x, y) for x, y, *_ in interior_coords])
# Create a new Polygon with 2D coordinates
return type(geom)(exterior_coords_2d, interior_coords_2d)
else:
return geom
def kml_to_geojson(kml_string):
k = kml.KML()
k.from_string(kml_string.encode('utf-8')) # Convert the string to bytes
features = list(k.features())
geojson_features = []
for feature in features:
geometry_2d = convert_3d_to_2d(feature.geometry)
geojson_features.append(geojson.Feature(geometry=geometry_2d))
geojson_data = geojson.FeatureCollection(geojson_features)
return geojson_data
# Calculate NDVI as Normalized Index
def reduce_zonal_ndvi(image, ee_object):
ndvi = image.normalizedDifference(['B8', 'B4']).rename('NDVI')
image = image.addBands(ndvi)
image = image.select('NDVI')
reduced = image.reduceRegion(
reducer=ee.Reducer.mean(),
geometry=ee_object.geometry(),
scale=10,
maxPixels=1e12
)
return image.set(reduced)
# Validate KML File for Single Polygon and return polygon information
def validate_KML_file(kml_file):
try:
gdf = gpd.read_file(kml_file)
except Exception as e:
ValueError("Input must be a valid KML file.")
if gdf.empty:
return {
'corner_points': None,
'area': None,
'perimeter': None,
'is_single_polygon': False}
polygon_info = {}
# Check if it's a single polygon or multipolygon
if isinstance(gdf.iloc[0].geometry, Polygon):
polygon_info['is_single_polygon'] = True
polygon = gdf.geometry.iloc[0]
# Calculate corner points in GCS projection
polygon_info['corner_points'] = [
(polygon.bounds[0], polygon.bounds[1]),
(polygon.bounds[2], polygon.bounds[1]),
(polygon.bounds[2], polygon.bounds[3]),
(polygon.bounds[0], polygon.bounds[3])
]
# Calculate Centroids in GCS projection
polygon_info['centroid'] = polygon.centroid.coords[0]
# Calculate area and perimeter in EPSG:7761 projection
# It is a local projection defined for Gujarat as per NNRMS
polygon = gdf.to_crs(epsg=7761).geometry.iloc[0]
polygon_info['area'] = polygon.area
polygon_info['perimeter'] = polygon.length
else:
polygon_info['is_single_polygon'] = False
polygon_info['corner_points'] = None
polygon_info['area'] = None
polygon_info['perimeter'] = None
polygon_info['centroid'] = None
ValueError("Input must be a single Polygon.")
return polygon_info
# Get Zonal NDVI
def get_zonal_ndvi(collection, geom_ee_object):
reduced_collection = collection.map(lambda image: reduce_zonal_ndvi(image, ee_object=geom_ee_object))
stats_list = reduced_collection.aggregate_array('NDVI').getInfo()
filenames = reduced_collection.aggregate_array('system:index').getInfo()
dates = [f.split("_")[0].split('T')[0] for f in reduced_collection.aggregate_array('system:index').getInfo()]
df = pd.DataFrame({'NDVI': stats_list, 'Date': dates, 'Imagery': filenames})
return df
def geojson_to_ee(geojson_data):
ee_object = ee.FeatureCollection(geojson_data)
return ee_object
def kml_to_gdf(kml_file):
try:
gdf = gpd.read_file(kml_file)
for i in range(len(gdf)):
geom = gdf.iloc[i].geometry
new_geom = convert_to_2d_geometry(geom)
gdf.loc[i, 'geometry'] = new_geom
print(gdf.iloc[i].geometry)
print(f"KML file '{kml_file}' successfully read")
except Exception as e:
print(f"Error: {e}")
return gdf
# put title in center
st.markdown("""
<style>
h1 {
text-align: center;
}
</style>
""", unsafe_allow_html=True)
st.title("Mean NDVI Calculator")
# get the start and end date from the user
col = st.columns(2)
start_date = col[0].date_input("Start Date", value=pd.to_datetime('2021-01-01'))
end_date = col[1].date_input("End Date", value=pd.to_datetime('2021-01-30'))
start_date = start_date.strftime("%Y-%m-%d")
end_date = end_date.strftime("%Y-%m-%d")
max_cloud_cover = st.number_input("Max Cloud Cover", value=20)
# Get the geojson file from the user
uploaded_file = st.file_uploader("Upload KML/GeoJSON file", type=["geojson", "kml"])
# Read the KML file
if uploaded_file is None:
file_name = "Bhankhara_Df_11_he_5_2020-21.geojson"
st.write(f"Using default file: {file_name}")
data = gpd.read_file(file_name)
with open(file_name) as f:
str_data = f.read()
else:
st.write(f"Using uploaded file: {uploaded_file.name}")
file_name = uploaded_file.name
bytes_data = uploaded_file.getvalue()
str_data = bytes_data.decode("utf-8")
if file_name.endswith(".geojson"):
geojson_data = json.loads(str_data)
elif file_name.endswith(".kml"):
geojson_data = json.loads(kml_to_gdf(str_data).to_json())
# Read Geojson File
ee_object = geojson_to_ee(geojson_data)
# Filter data based on the date, bounds, cloud coverage and select NIR and Red Band
collection = ee.ImageCollection("COPERNICUS/S2_SR_HARMONIZED").filterBounds(ee_object).filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', max_cloud_cover)).filter(ee.Filter.date(start_date, end_date)).select(['B4', 'B8'])
polygon_info = validate_KML_file(str_data)
if polygon_info['is_single_polygon']:
# Read KML file
geom_ee_object = ee.FeatureCollection(geojson_data)
# Add buffer of 100m to ee_object
buffered_ee_object = geom_ee_object.map(lambda feature: feature.buffer(100))
# Filter data based on the date, bounds, cloud coverage and select NIR and Red Band
collection = ee.ImageCollection("COPERNICUS/S2_SR_HARMONIZED").filterBounds(geom_ee_object).filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 20)).filter(ee.Filter.date('2022-01-01', '2023-01-01')).select(['B4', 'B8'])
# Get Zonal NDVI based on collection and geometries (Original KML and Buffered KML)
df_geom = get_zonal_ndvi(collection, geom_ee_object)
df_buffered_geom = get_zonal_ndvi(collection, buffered_ee_object)
# Merge both Zonalstats and create resultant dataframe
resultant_df = pd.merge(df_geom, df_buffered_geom, on='Date', how='inner')
resultant_df = resultant_df.rename(columns={'NDVI_x': 'AvgNDVI_Inside', 'NDVI_y': 'Avg_NDVI_Buffer'})
resultant_df['Ratio'] = resultant_df['AvgNDVI_Inside'] / resultant_df['Avg_NDVI_Buffer']
resultant_df.drop(columns=['Imagery_y'], inplace=True)
# Re-order the columns of the resultant dataframe
resultant_df = resultant_df[['Date', 'Imagery_x', 'AvgNDVI_Inside', 'Avg_NDVI_Buffer', 'Ratio']]
# Map = geemap.Map(center=(polygon_info['centroid'][1],polygon_info['centroid'][0]) , zoom=12)
# Map.addLayer(geom_ee_object, {}, 'Layer1')
# Map.addLayer(buffered_ee_object, {}, 'Layer2')
# plot the time series
st.write("Time Series Plot")
st.line_chart(resultant_df.set_index('Date'))
#st.write(f"Overall Mean NDVI: {resultant_df['Mean NDVI'].mean():.2f}")
else:
print("Input must be a single Polygon.")