# Create Simple Maps Using `usamap`

This example shows how to create `axesm`-based maps of the United States by using the `usamap` function. The `usamap` function lets you make maps of the United States as a whole, just the conterminous portion (the "lower 48" states), groups of states, or a single state. The map you create with the `usamap` function has a labelled grid fitted around the area you specify but contains no data, allowing you to generate the kind of map you want using display functions such as the `geoshow` function.

Specify map limits and set up an `axesm`-based map. This example creates a map of the Chesapeake Bay region.

```latlim = [37 40]; lonlim = [-78 -74]; figure ax = usamap(latlim,lonlim); axis off```

Determine the map projection used by the `usamap` function. The Lambert Conformal Conic projection is often used for maps of the conterminous United States.

`getm(gca,'MapProjection')`
```ans = 'lambert' ```

Use the `readgeotable` function to read U.S. state polygon boundaries from the shapefile called `usastatehi.shp`. The function returns the data in a geospatial table.

`states = readgeotable('usastatehi.shp');`

Create a symbol specification to create a political map using the `polcmap` function.

```h = height(states); faceColors = makesymbolspec('Polygon',... {'INDEX',[1 h],'FaceColor',polcmap(h)});```

Display the filled polygons by using the `geoshow` function.

`geoshow(states,'SymbolSpec',faceColors)`

Extract the names for states within the map limits and use the `textm` function to plot them at the label points provided by the geospatial table. Because `polcmap` assigns random pastel colors to patches, your map might look different than this example.

```for k = 1:h labelPointIsWithinLimits = ... latlim(1) < states.LabelLat(k) &&... latlim(2) > states.LabelLat(k) &&... lonlim(1) < states.LabelLon(k) &&... lonlim(2) > states.LabelLon(k); if labelPointIsWithinLimits textm(states.LabelLat(k),... states.LabelLon(k), states.Name(k),... 'HorizontalAlignment','center') end end textm(38.2,-76.1,' Chesapeake Bay ',... 'fontweight','bold','Rotation',270)```