Historical Map Skill Skill

Historical Map Skill

Generate interactive historical maps as self-contained HTML files powered by Leaflet.js.

Critical: Things Claude Won't Know Without This Skill

The output is a standalone HTML file

The Python script generates a complete HTML file that loads Leaflet.js from CDN. No server, no build step, no pip install — just open in a browser. Zero external Python dependencies.

Pre-configured basemaps are available

from scripts.map_builder import BASEMAPS
# Keys: "osm", "watercolor", "toner_lite", "carto_light", "carto_dark"

carto_light (CartoDB Positron) is the default — a clean, muted basemap ideal for historical data overlays.

Historical world boundaries are one method call away

54 pre-built GeoJSON boundary files (123,000 BCE – 2010 CE) from aourednik/historical-basemaps:

m.add_historical_boundaries("200_bce")   # World c. 200 BCE
m.add_historical_boundaries("100_ce")    # World c. 100 CE
m.add_historical_boundaries("1400_ce")   # World c. 1400 CE

These are fetched at runtime from GitHub by the browser. Each polygon has a NAME property for popups/tooltips.

Available boundary periods

BCE: 2000_bce, 1000_bce, 500_bce, 323_bce, 200_bce, 100_bce, 1_bce

CE: 100_ce through 1994_ce in ~100-year increments, plus special years: 1279_ce, 1492_ce, 1783_ce, 1815_ce, 1880_ce, 1920_ce, 1938_ce, 1945_ce, 1960_ce

Colored marker icons are loaded from GitHub

Marker colors: blue, gold, red, green, orange, yellow, violet, grey, black. These use the pointhi/leaflet-color-markers CDN icons.

Academia Sinica provides Chinese historical map tiles

WMTS tiles based on Tan Qixiang's Historical Atlas of China (谭其骧《中国历史地图集》), covering 222 BCE – 1911 CE:

m.add_wms_layer(
    "https://gis.sinica.edu.tw/tileserver/wmts",
    layers="LAYER_ID",
    name="Tang Dynasty Map",
)

MapWarper provides crowdsourced georeferenced historical maps

m.add_mapwarper_layer(14781, name="1860 Beijing")

Find map IDs by browsing https://mapwarper.net/

Workflow

1. Build a map with the Python builder

from scripts.map_builder import HistoricalMapBuilder

m = HistoricalMapBuilder(
    title="Tang Dynasty China",
    center=(35.0, 108.0),
    zoom=5,
    basemap="carto_light",   # or "osm", "watercolor", "toner_lite", "carto_dark"
)

# Add historical boundaries
m.add_historical_boundaries("700_ce", name="World c. 700 CE")

# Add markers
m.add_marker(34.26, 108.94, "Chang'an (長安)",
    popup="<b>Chang'an</b><br>Capital of the Tang Dynasty",
    color="red", group="Capitals")

m.add_marker(34.75, 113.65, "Luoyang (洛陽)",
    popup="<b>Luoyang</b><br>Eastern capital",
    color="red", group="Capitals")

m.add_marker(31.23, 121.47, "Huating (華亭)",
    popup="<b>Huating</b><br>Modern-day Shanghai area",
    color="blue", group="Cities")

# Add GeoJSON data (inline)
m.add_geojson(
    geojson_data,              # Any GeoJSON dict
    name="Grand Canal",
    style={"color": "#0077b6", "weight": 3},
    popup_property="name",     # Show feature.properties.name on click
    tooltip_property="name",   # Show on hover
)

# Add GeoJSON from URL (fetched by browser at runtime)
m.add_geojson_url(
    "https://example.com/data.geojson",
    name="Trade Routes",
    style={"color": "#e63946", "weight": 2, "dashArray": "5 3"},
)

# Add a scanned historical map as image overlay
m.add_image_overlay(
    "https://example.com/old_map.jpg",
    bounds=((30.0, 100.0), (42.0, 120.0)),  # (SW corner, NE corner)
    name="Historical Map",
    opacity=0.6,
)

# Add custom tile layer
m.add_tile_layer(
    "https://tiles.example.com/{z}/{x}/{y}.png",
    name="Custom Tiles",
    opacity=0.7,
)

# Save
m.save_html("tang_dynasty.html")

2. Open the HTML file

open tang_dynasty.html

Interactive features: pan, zoom, click markers for popups, hover for tooltips, toggle layers on/off via the layer control panel.

3. Combine with other skills

# Use CBDB data to place historical figures on the map
# Use CHGIS/TGAZ data for accurate historical coordinates
# Use CJK Calendar to annotate dates

Builder API Reference

Constructor

HistoricalMapBuilder(
    title="Map Title",
    center=(lat, lng),         # Default: (35.0, 105.0)
    zoom=5,                    # Default: 5, range 0-18
    basemap="carto_light",     # Key from BASEMAPS or "none"
)

Methods

| Method | Description | |--------|-------------| | add_marker(lat, lng, label, *, popup, tooltip, color, group) | Colored marker with popup/tooltip | | add_geojson(data, name, *, style, popup_property, tooltip_property) | Inline GeoJSON overlay | | add_geojson_url(url, name, *, style, popup_property, tooltip_property) | Remote GeoJSON (fetched by browser) | | add_historical_boundaries(period, *, name, style) | World boundaries from historical-basemaps | | add_tile_layer(url, name, *, attribution, max_zoom, opacity, overlay) | XYZ tile layer | | add_mapwarper_layer(map_id, name, *, opacity) | MapWarper georeferenced map | | add_wms_layer(url, layers, name, *, fmt, transparent, opacity) | WMS tile layer | | add_image_overlay(url, bounds, name, *, opacity) | Georeferenced image overlay | | save_html(path) | Write standalone HTML file |

Leaflet Style Options

style = {
    "color": "#e63946",      # Stroke color (hex or CSS name)
    "weight": 2,             # Stroke width in pixels
    "opacity": 1,            # Stroke opacity (0-1)
    "fillColor": "#f1faee",  # Fill color (defaults to color)
    "fillOpacity": 0.2,      # Fill opacity (0-1)
    "dashArray": "5 3",      # Dash pattern
}

API Etiquette

Historical boundaries: Fetched from GitHub raw URLs — no rate limit, but cache results for repeated use
MapWarper: Public tile service — use reasonably
Academia Sinica: Public WMTS — use for academic purposes
Leaflet CDN: No rate limits on unpkg.com

Related Skills

cbdb-api / cbdb-local: Retrieve biographical data with geographic coordinates to place historical figures on maps
chgis-tgaz / tgaz-sqlite: Look up historical place names with coordinates for accurate marker placement
cjk-calendar: Convert lunisolar dates for timeline annotations
historical-timeline: Create a companion timeline visualization alongside the map
wikidata-search: Retrieve coordinates and geographic identifiers for historical places

Resources

references/map_reference.md — Complete reference for basemaps, tile servers, boundary datasets, and Leaflet configuration
scripts/map_builder.py — Python builder with zero dependencies for generating standalone HTML maps

Agent Skills: Historical Map Skill

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Skill Files