pages/10_🌍_Earth_Engine_Datasets.py

import ee
import streamlit as st
import geemap.foliumap as geemap

st.set_page_config(layout="wide")

st.sidebar.title("About")
st.sidebar.info(
    """
    Web App URL: <https://geospatial.streamlitapp.com>
    GitHub repository: <https://github.com/giswqs/streamlit-geospatial>
    """
)

st.sidebar.title("Contact")
st.sidebar.info(
    """
    Qiusheng Wu: <https://wetlands.io>
    [GitHub](https://github.com/giswqs) | [Twitter](https://twitter.com/giswqs) | [YouTube](https://www.youtube.com/c/QiushengWu) | [LinkedIn](https://www.linkedin.com/in/qiushengwu)
    """
)


def nlcd():

    # st.header("National Land Cover Database (NLCD)")

    row1_col1, row1_col2 = st.columns([3, 1])
    width = 950
    height = 600

    Map = geemap.Map(center=[40, -100], zoom=4)

    # Select the seven NLCD epoches after 2000.
    years = ["2001", "2004", "2006", "2008", "2011", "2013", "2016", "2019"]

    # Get an NLCD image by year.
    def getNLCD(year):
        # Import the NLCD collection.
        dataset = ee.ImageCollection("USGS/NLCD_RELEASES/2019_REL/NLCD")

        # Filter the collection by year.
        nlcd = dataset.filter(ee.Filter.eq("system:index", year)).first()

        # Select the land cover band.
        landcover = nlcd.select("landcover")
        return landcover

    with row1_col2:
        selected_year = st.multiselect("Select a year", years)
        add_legend = st.checkbox("Show legend")

    if selected_year:
        for year in selected_year:
            Map.addLayer(getNLCD(year), {}, "NLCD " + year)

        if add_legend:
            Map.add_legend(
                legend_title="NLCD Land Cover Classification", builtin_legend="NLCD"
            )
        with row1_col1:
            Map.to_streamlit(width=width, height=height)

    else:
        with row1_col1:
            Map.to_streamlit(width=width, height=height)


def search_data():

    # st.header("Search Earth Engine Data Catalog")

    Map = geemap.Map()

    if "ee_assets" not in st.session_state:
        st.session_state["ee_assets"] = None
    if "asset_titles" not in st.session_state:
        st.session_state["asset_titles"] = None

    col1, col2 = st.columns([2, 1])

    dataset = None
    with col2:
        keyword = st.text_input(
            "Enter a keyword to search (e.g., elevation)", "")
        if keyword:
            ee_assets = geemap.search_ee_data(keyword)
            asset_titles = [x["title"] for x in ee_assets]
            asset_types = [x["type"] for x in ee_assets]

            translate = {
                "image_collection": "ee.ImageCollection('",
                "image": "ee.Image('",
                "table": "ee.FeatureCollection('",
                "table_collection": "ee.FeatureCollection('",
            }

            dataset = st.selectbox("Select a dataset", asset_titles)
            if len(ee_assets) > 0:
                st.session_state["ee_assets"] = ee_assets
                st.session_state["asset_titles"] = asset_titles

            if dataset is not None:
                with st.expander("Show dataset details", True):
                    index = asset_titles.index(dataset)

                    html = geemap.ee_data_html(
                        st.session_state["ee_assets"][index])
                    html = html.replace("\n", "")
                    st.markdown(html, True)

                ee_id = ee_assets[index]["id"]
                uid = ee_assets[index]["uid"]
                st.markdown(f"""**Earth Engine Snippet:** `{ee_id}`""")
                ee_asset = f"{translate[asset_types[index]]}{ee_id}')"
                vis_params = st.text_input(
                    "Enter visualization parameters as a dictionary", {}
                )
                layer_name = st.text_input("Enter a layer name", uid)
                button = st.button("Add dataset to map")
                if button:
                    vis = {}
                    try:
                        if vis_params.strip() == "":
                            # st.error("Please enter visualization parameters")
                            vis_params = "{}"
                        vis = eval(vis_params)
                        if not isinstance(vis, dict):
                            st.error(
                                "Visualization parameters must be a dictionary")
                        try:
                            Map.addLayer(eval(ee_asset), vis, layer_name)
                        except Exception as e:
                            st.error(f"Error adding layer: {e}")
                    except Exception as e:
                        st.error(f"Invalid visualization parameters: {e}")

            with col1:
                Map.to_streamlit()
        else:
            with col1:
                Map.to_streamlit()


def app():
    st.title("Earth Engine Data Catalog")

    apps = ["Search Earth Engine Data Catalog",
            "National Land Cover Database (NLCD)"]

    selected_app = st.selectbox("Select an app", apps)

    if selected_app == "National Land Cover Database (NLCD)":
        nlcd()
    elif selected_app == "Search Earth Engine Data Catalog":
        search_data()


app()