Add Map Maker streamlit example

Author: gjbex

source-code/streamlit/map_maker/map_maker_app.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+import altair_saver
+from map_maker_lib import create_topo_data, read_file, validate_data, \
+        create_plot, DATA_TYPES, DELIMITERS, COLOR_SCHEMES
+import streamlit as st
+
+
+BE_GEO_URL = 'https://gist.githubusercontent.com/jandot/ba7eff2e15a38c6f809ba5e8bd8b6977/raw/eb49ce8dd2604e558e10e15d9a3806f114744e80/belgium_municipalities_topojson.json'
+BE_MUNICIPALITIES_FEATURE = 'BE_municipalities'
+
+
+if __name__ == '__main__':
+    '''# Map Maker
+    '''
+
+    file_column1, file_column2 = st.beta_columns(2)
+    with file_column1:
+        data_file = st.file_uploader('Data file')
+    with file_column2:
+        encoding = st.selectbox('File encoding', ('utf-8', 'iso-8859-1'))
+        delimiter = DELIMITERS[st.selectbox('Data delimiter',
+                                             list(DELIMITERS.keys()))]
+
+    topo_municipalities = create_topo_data(BE_GEO_URL, BE_MUNICIPALITIES_FEATURE)
+
+    if data_file:
+        file_name = data_file.name
+        bytes_array = data_file.read()
+        data = read_file(file_name, bytes_array, encoding=encoding, delimiter=delimiter)
+        validate_data(data) 
+
+        data_column1, data_column2, data_column3 = st.beta_columns(3)
+        with data_column1:
+            column_name = st.selectbox('Data column',
+                                       [column for column in data.columns
+                                        if column not in ('nis_code',)])
+        with data_column2:
+            data_type = DATA_TYPES[st.selectbox('Data type', list(DATA_TYPES.keys()))]
+        with data_column3:
+            color_scheme = st.selectbox('Color scheme', COLOR_SCHEMES)
+        tooltip_names = st.multiselect('Tooltip columns',
+                                       [column for column in data.columns
+                                        if column not in ('nis_code',)])
+        plot = create_plot(topo_data=topo_municipalities, data=data,
+                           column_name=column_name, data_type=data_type,
+                           tooltip_columns=tooltip_names, scheme=color_scheme)
+        st.write(plot)

source-code/streamlit/map_maker/map_maker_lib.py

@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+
+import altair as alt
+import io
+import numpy as np
+import pandas as pd
+import random
+
+
+DATA_TYPES = {
+    'quantitative': 'Q',
+    'ordinal': 'O',
+    'nominal': 'N',
+}
+
+DELIMITERS = {
+    'comma': ',',
+    'semi-colon': ';',
+    'space': ' ',
+    'tab': '\t',
+}
+
+COLOR_SCHEMES = (
+    'reds',
+    'blues',
+    'category10',
+)
+
+
+def create_topo_data(url, feature):
+    return alt.topo_feature(url, feature)
+
+
+
+def read_data(uri, encoding=None, delimiter=None):
+    if uri.lower().endswith('.csv'):
+        return pd.read_csv(uri, encoding=encoding, delimiter=delimiter)
+    elif uri.lower().endswith('.xlsx'):
+        return pd.read_excel(uri)
+    else:
+        raise ValueError(f'file type of ""{uri}"" is unknown')
+
+
+def read_file(name, byte_stream, encoding=None, delimiter=None):
+    if name.lower().endswith('.csv'):
+        return pd.read_csv(io.BytesIO(byte_stream), encoding=encoding,
+                           delimiter=delimiter)
+    elif name.lower().endswith('.xlsx'):
+        return pd.read_excel(io.BytesIO(byte_stream))
+    else:
+        raise ValueError(f'file type of ""{name}"" is unknown')
+
+
+def validate_data(data):
+    if len(data.columns) < 2:
+        raise ValueError('data should have at least a NIS code and a data column')
+    nis_code_pos = [idx for idx, col_name in enumerate(data.columns)
+                        if col_name.lower() == 'niscode']
+    if len(nis_code_pos) > 1:
+        raise ValueError('multiple columns have NIS code name')
+    elif len(nis_code_pos) == 0:
+        raise ValueError('NIS code column is missing')
+    else:
+        columns = list(data.columns)
+        columns[nis_code_pos[0]] = 'niscode'
+        data.columns = columns
+    if data.niscode.dtype != np.int64:
+        raise ValueError('data type for NIS code is incorret, should be integer')
+
+
+def create_plot(topo_data, data, column_name, data_type, tooltip_columns=None,
+                stroke='lightgrey', strokeWidth=0.5, legend_title=None,
+                scheme='reds'):
+    lookup_columns = [column_name]
+    if tooltip_columns is not None:
+        lookup_columns.extend(tooltip_columns)
+    if legend_title is None:
+        legend_title = column_name
+    return alt.Chart(topo_data)\
+            .mark_geoshape(stroke=stroke, strokeWidth=strokeWidth)\
+            .encode(
+                color=alt.Color(f'{column_name}:{data_type}',
+                                legend=alt.Legend(title=legend_title), 
+                                scale=alt.Scale(scheme=scheme)),
+                tooltip=[f'{column}:N' for column in tooltip_columns],
+            ).transform_lookup(
+                lookup='properties.CODE_INS',
+                from_=alt.LookupData(data, 'niscode', lookup_columns)
+            )
+
+
+def create_quantitative_plot(topo_data, data, column_name,
+                             stroke='lightgrey', strokeWidth=0.5,
+                             legend_title=None, scheme='reds'):
+    return create_plot(topo_data, data, column_name, 'Q',
+                       stroke, strokeWidth, legend_title, scheme)
+
+
+def create_nominal_plot(topo_data, data, column_name,
+                        stroke='lightgrey', strokeWidth=0.5,
+                        legend_title=None, scheme='reds'):
+    return create_plot(topo_data, data, column_name, 'N',
+                       stroke, strokeWidth, legend_title, scheme)