Locator Map Generator: Nest Your Site in Its Region and Country

What is a locator map and why researchers need one

A locator map (also called a key map or inset map) answers the first question every reviewer asks about a figure: where is this? It places your study site in geographic context by nesting it inside progressively larger areas — a district inside a state inside a country — so a reader who has never heard of your field site can orient themselves in seconds.

For a paper, thesis or grant, this context is not optional. A close-up of your sampling grid, watershed or plot is meaningless without a panel showing the country and region it sits in. A good locator map generator produces this cascade automatically instead of forcing you to hand-align insets in Illustrator or QGIS. If you also need a full detail map of the site itself, pair this with the study area map generator.

Make a locator map in Python

The fastest route is the cascade template: pass an ordered list of administrative steps from broad to specific, and AcadGIS draws each level as its own panel with connecting arrows linking parent to child.

Each step is a (level, name) pair. The generator loads the boundaries, highlights the correct child inside each parent, and arranges the panels left-to-right with a shared, publication-ready style. Supported levels are country, state, district, division and upazila, depending on the country's data.

import acadgis as agis
fig = agis.study_area(
    "India",
    steps=[("state", "Uttarakhand"), ("district", "Dehradun")],
    template="cascade",
    labels=True,
)
agis.save("locator.png", dpi=300)

The fluent builder for more control

If you prefer to read the geography as a sentence, the StudyArea builder does the same job with a fluent, chainable call. Set the context level for the widest panel, zoom into the region, then render the figure — the connecting arrows and highlight boxes are added for you.

This form is handy when you want to reuse one context object across several sites, or when a co-author needs to follow the logic of the nesting at a glance.

import acadgis as agis
fig = (agis.StudyArea("USA", context_level="state")
          .zoom_into("California", detail_level="district")
          .figure(suptitle="Study site: Los Angeles County"))
agis.save("la_locator.png", dpi=300)

Examples and variations

The same locator generator adapts to different scales and story-telling needs:

• Country-in-the-world: when the audience is international, start with a world panel that highlights just the country — the same idea powers the world map country highlighter.
• Region-in-context: highlight one state among its neighbours to show relative position, as with West Bengal inside India.
• Site cascade: the full country to region to district chain shown above, ideal for a thesis frontispiece or a paper's Figure 1.

Because every panel is a real map object, you can layer terrain, rivers or points onto the detail panel before saving — useful when the locator doubles as the site overview in a thesis map.

Data sources and tips

Administrative boundaries come from GADM (country, state, district and finer levels) and Natural Earth (world and coastline context). Bangladesh, Iraq, India and the USA ship bundled with AcadGIS, so those locator maps build fully offline; every other country downloads by name on first use and is then cached.

A few tips for clean locator figures:

• Keep the cascade to three or four panels — country, region, site is usually enough, and more panels shrink each one below legibility.
• Turn labels=True only on panels where names fit; on the smallest inset a single highlight box reads more clearly than crowded text.
• Export to PDF or SVG for vector-crisp insets in a typeset paper, or PNG at 300+ DPI for slides and posters.
• Let AcadGIS pick a sensible projection per panel rather than forcing one global projection onto a small district.

Frequently asked questions