Show only polygon of interest in Atlas, QGIS

Zoom In: Showing Only Your Area of Interest in QGIS Atlas

QGIS, or Quantum GIS if you’re feeling formal, is a fantastic open-source tool for playing around with maps and spatial data. Think of it as your digital cartographer’s Swiss Army knife. One of its coolest tricks is the Atlas tool. Ever needed to churn out a whole series of maps, all styled the same but each spotlighting a different area? Atlas is your friend. It lets you automatically generate these maps using a coverage layer – basically, a layer that tells QGIS what areas to focus on. But here’s the thing: sometimes you only want to highlight that specific area, masking out everything else. It’s like putting a spotlight on center stage. So, how do you do it? Let’s dive in.

Cracking the Atlas Code

The QGIS Atlas is built right in, so no need to go hunting for plugins. It’s all about creating map books from a shapefile or spatial dataset. You pick a layer with geometries – think of it as your guide – and Atlas cleverly adjusts the map view to each shape in that layer. Trust me, this is a huge time-saver. Instead of manually creating hundreds of maps, you can let Atlas do the heavy lifting in minutes.

Method 1: The “Inverted Polygons” Magic Trick

Here’s a simple way to focus on your polygon of interest: the “Inverted Polygons” style. It’s like saying, “show me everything except this,” effectively masking out the unwanted areas.

Here’s the breakdown:

Method 2: Rule-Based Styling – Get Fancy with Atlas Feature ID

Want a bit more control? Try rule-based styling combined with the Atlas feature ID. This is where things get interesting, especially when you’re using the Atlas tool.

Let’s break it down:

Now, as Atlas steps through each polygon, only the current one will be visible. Pretty neat, huh?

Method 3: Clipping with Atlas Feature – The Modern Way (Newer QGIS)

If you’re rocking a newer version of QGIS, you’re in luck! There’s a built-in clipping feature right in the Atlas tool. It’s a super direct way to clip your map layers to the current Atlas feature.

Here’s how it works:

Extra Tips and Tricks

• Data-Driven Visibility: Want even more control? Use data-driven overrides to control layer visibility within Atlas. Add a field to your coverage layer that specifies which layers should be visible for each feature.
• Expression Power: Expressions are your friend! Use them in labels and styles to dynamically display info about the current Atlas feature. Show the polygon’s name, ID, whatever you need.
• Performance Matters: Big datasets can slow things down. Simplify your data or use spatial indexes to speed things up.
• No Data, No Problems: When clipping rasters (images), define a “No Data” value to avoid weird artifacts.
• CRS Harmony: Make sure all your layers are using the same Coordinate Reference System (CRS) to avoid alignment headaches.

With these techniques in your toolbox, you’ll be whipping up stunning QGIS Atlases that highlight exactly what you want, every time. Whether you’re into inverted polygons, rule-based styling, or the built-in clipping, QGIS gives you the power to create amazing maps. Now go get mapping!