Creating polygon with one click in QGIS?

Ditch the Drudgery: One-Click Polygons in QGIS (Seriously!)

Okay, let’s be honest: digitizing polygons can feel like a total slog. Click, click, click… it’s enough to make anyone’s eyes glaze over. But what if I told you there are ways to seriously speed things up in QGIS? We’re talking about methods that can feel almost like creating polygons with a single click. Sounds too good to be true? Stick with me.

QGIS, being the awesome open-source GIS powerhouse that it is, offers some clever tricks for making polygon creation way less painful. Forget endlessly clicking around a shape; these techniques can dramatically cut down on the clicks, and boost your accuracy too. So, let’s dive into some ninja-level tactics for whipping up polygons in record time.

Trace Digitizing: Your New Best Friend

First up, let’s talk about the “Trace Digitizing” tool. If you’re rocking QGIS version 2.14 or later, this little gem is built right in, and it’s a game-changer. Think of it as “auto-pilot” for tracing existing features. I remember the first time I used this – I literally gasped at how much time it saved me tracing a complex coastline!

Here’s the lowdown on using Trace Digitizing:

Plugins: Because QGIS Can Always Do More

QGIS’s plugin library is like a candy store for GIS nerds. Seriously, there are plugins for everything, and polygon creation is no exception.

• Bunting Labs AI Vectorizer: This one’s pretty wild. It uses AI to automatically trace map features. Okay, it’s not exactly one-click, but it gets darn close, especially for those twisty, complicated shapes. Just be aware that you’ll need a Bunting Labs account, and the free version has some limits.
• Digitizing Tools: This plugin is more of an all-around digitizing enhancer. It’s got tools for merging, splitting, and rotating features, which can definitely speed things up.
• Rectangle Wrangling: Need rectangles? Check out QRectangleCreator and QuickRectangleCreator. These let you whip up rectangles with specific sizes and rotations in a snap.
• Click-to-Polygon: The “Polygon by clicking in map image” tool does exactly what it says on the tin. Click on the map, and boom, a polygon appears on your editable layer.

Other Tricks Up Your Sleeve

Trace Digitizing and plugins are awesome, but don’t forget these other handy techniques:

• Shape Digitizing Toolbar: This toolbar is your friend when you’re dealing with rectangular buildings. It helps you keep those edges nice and perpendicular. Just right-click on the toolbar area and turn it on.
• Advanced Digitizing Panel: Need super-precise control? This panel lets you punch in exact measurements, angles, and coordinates. Find it under View > Panels > Advanced Digitizing Panel.
• Vertex Tool: Your Fine-Tuning Friend: Sometimes, you just need to nudge a vertex or two. The Vertex Tool lets you do exactly that. Activate it and select Vertex Tool (Current Layer) to tweak those points.

When in Doubt, Convert!

Sometimes, the fastest way to get a polygon is to cheat a little… by converting existing data!

• Lines to Polygons: Got closed line features? The “Lines to Polygons” tool in the Processing Toolbox will turn them into polygons in a jiffy.
• Raster to Vector: Scanned maps or aerial photos got you down? Use “Polygonize” (GDAL) or “Raster pixels to polygons” to convert those rasters into glorious vector polygons.

Pro Tips for Maximum Polygon Power

No matter which method you choose, keep these golden rules in mind:

• Snapping, Snapping, Snapping: Seriously, get your snapping settings dialed in. It’s the key to accurate and efficient digitizing.
• Keyboard Shortcuts are Your Friend: Learn those shortcuts! They’ll save you a ton of time in the long run.
• Plan of Attack: Before you start clicking like crazy, take a minute to plan your digitizing strategy. Think about the order you’ll digitize features to minimize wasted movement.

So, there you have it! With these tips and tricks, you’ll be creating polygons in QGIS faster and more efficiently than ever before. Now go forth and digitize!