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# """Documentation page for Streamlit app.""" | |
import streamlit as st | |
from src.config_parameters import params | |
from src.utils import ( | |
add_about, | |
set_doc_page_style, | |
toggle_menu_button, | |
) | |
# Page configuration | |
st.set_page_config(layout="wide", page_title=params["browser_title"]) | |
# If app is deployed hide menu button | |
toggle_menu_button() | |
# Create sidebar | |
add_about() | |
# Set page style | |
set_doc_page_style() | |
# Page title | |
st.markdown("# Documentation") | |
# First section | |
st.markdown("## Methodology") | |
st.markdown( | |
""" | |
This tool does not produce its own forecasts; it leverages the flood forecasts created | |
by the GloFAS Global Flood Monitoring tool and aims to make them conveniently accessible. | |
The GFM products are generated using flood detection algorithms applied to Sentinel-1 satellite data, | |
which captures radar imagery in all weather conditions. Sentinel-1 data, | |
acquired in Interferometric Wide-swath mode and VV-polarization, is preprocessed into Analysis-Ready Data | |
(ARD) with a 10x10 m pixel resolution. Three flood detection algorithms are then run in parallel on | |
this ARD: | |
- **HASARD (by LIST)**: Uses image comparison and statistical modeling to detect changes in | |
flood-related signals. | |
- **Alg2 (by DLR)**: Applies fuzzy logic and hierarchical thresholding to classify flooded areas. | |
- **Alg3 (by TUW)**: Leverages long-term signal history and statistical modeling for efficient | |
global flood mapping. | |
Each algorithm independently classifies flooded pixels, and their results are | |
combined into a consensus map. A pixel is marked as flooded if at least two of the three algorithms | |
agree. This ensemble approach improves accuracy and ensures near-real-time flood monitoring globally. | |
Detailed documentation on the methodology is available on the GloFAS | |
website: https://global-flood.emergency.copernicus.eu/technical-information/glofas-gfm/ | |
The GloFAS documentation mentions 11 products that are published. The products used in this tool are | |
- **The observed flood extent**: these are the floods shown in red when analyzing floods on the | |
"Flood Analysis" page | |
- **The Sentinel-1 footprint**: this is the bounding box of the Sentinel-1 satellite image that contains the | |
flood, shown in yellow when analyzing floods | |
""" | |
) | |
# Second section | |
st.markdown("## Radar imagery for flood detection") | |
st.markdown( | |
""" | |
As described above, GFM uses Sentinel-1 data as the basis for its flood forecast. | |
Sentinel-1 data is the result of measurements from a constellation of two | |
satellites, assing over the same areas following the same orbit on average | |
every 6 days. The figure below shows an overview of the Sentinel-1 observation | |
plan, where pass directions and coverage frequencies are highlighted. | |
More detailed documentation on Sentinel-1 can be found on the Copernicus website: | |
https://sentiwiki.copernicus.eu/web/sentinel-1 | |
""", | |
unsafe_allow_html=True, | |
) | |
# Add image satellite overview | |
st.image( | |
"%s" % params["url_sentinel_img"], | |
width=1000, | |
) | |