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🛠️ Polygon Adjuster Editing Tool

This tool allows you to easily move polygon vertices or adjust side lengths directly on your QGIS map using a guided, click-based process. It's designed for simplicity, precision, and clarity.

✅ Prerequisites​

  • You must be editing a polygon layer.

  • Ensure the layer is in editing mode (pencil icon activated).

🔄 Tool Workflow Overview​

  1. Click a polygon on the map.

  2. Click one of its vertices.

  3. Choose an operation from the dialog:

    • Move a vertex by a given distance.

    • Set the length of one side of the polygon.

  4. Click a direction on the map to apply your change.

  5. Confirm or cancel the operation.

🧭 Step-by-Step Instructions​

🟩 Step 1: Activate the Tool​

From your plugin panel or button (depending on how it's integrated), click to activate the Unified Polygon Edit Tool.

A message will appear:

“Click polygon, then click a vertex, then follow prompts.”

🟩 Step 2: Select a Polygon​

  • Left-click anywhere inside a polygon.

  • A message appears:

    “Polygon selected. Now click a vertex of this polygon.”

  • Shows the lengths of all sides of the polygon

  • If nothing happens:

    • Ensure you're clicking on a polygon from an editable layer.

    • Make sure the layer is in editing mode (pencil icon enabled).

    • Zoom in to the polygon and left-click inside its boundary to select it.

🟩 Step 3: Select a Vertex​

  • Hover near the polygon’s edge; a green cross appears on a vertex.

  • Click that highlighted vertex.

  • If valid, a pop-up dialog appears to select the operation and distance/length.

🟩 Step 4: Choose Operation in Dialog​

You’ll see two options:

  • Move Vertex by Distance
    Move the selected vertex a certain distance in a direction you will choose on the map.

  • Set Polygon Side Length
    Resize one side of the polygon to a specific length, keeping one vertex fixed.

Enter a length in map units and press OK.

warning

⚠️ Distance must not be zero. Side length must be positive.

🟩 Step 5: Choose Direction​

  • A message appears:

    “Click to set move direction” or
    “Click to select side direction”

  • Move your mouse to the desired direction. A blue preview line shows your adjustment.

  • Click once to confirm the direction.

🟩 Step 6: Confirm Change​

A confirmation dialog appears, showing:

  • Distance and angle (for vertex move), or

  • Old vs. new length (for side adjustment)

Click Yes to apply the change, or No to cancel.

🧹 Step 7: Finish or Reset​

  • You can now start a new operation from Step 2.

  • Or right-click anywhere on the map to reset the tool.

A message appears:

“Ready. Right-click to reset, or left-click to start new operation.”

❗ Error Messages & Hints​

MessageMeaning / Suggestion
"No polygon found"You didn’t click inside a valid polygon. Try again.
"Layer Not Editable"Enable edit mode for that layer (click the pencil icon).
"No vertex found"You clicked too far from a vertex. Zoom in and try again.
"Invalid side length"Selected side is too short or undefined. Pick another vertex.

💡 Tips​

  • Zoom in close for better accuracy when selecting vertices or directions.

  • The green dot shows the selected vertex.

  • The orange X shows your direction click.

  • The preview lines help visualize before confirming.

🛑 To Exit the Tool​

Just select any other QGIS tool or press the Escape key/ Right click