How It Works

Learn how to use the Geometric Measurement Tool

What is the Geometric Measurement Tool?

The Geometric Measurement Tool is a powerful web application designed to measure complex geometries in images. It's perfect for analyzing:

Photos

Measure distances and areas in regular photographs

Aerial Imagery

Analyze distances and areas from drone or satellite photos

Maps & PDFs

Take measurements directly from map images or PDF plans

Interface Overview

The tool is organized into four areas for a clean, focused workflow:

Left Sidebar

Icon-only tool buttons grouped by function: upload, draw tools, edit, viewport, and modes. Hover for tooltips.

Canvas

The main drawing area. Pan with Alt+drag or the Hand tool, zoom with scroll wheel.

Right Panel

Reference & scale setup, measurements list, summary totals, edit controls, and project save/load.

Status Bar

Contextual tips that guide you step by step, plus SNAP/ORTO indicators and zoom level.

How to Use

1

Upload Your Image

Click the Upload button at the top of the left sidebar. Select a photo, aerial image, map, or PDF file. The image will appear on the canvas, ready for measurements.

2

Draw a Reference Line

Select the Line tool from the sidebar and draw a line on an object with a known measurement. The line will be automatically selected when you finish drawing.

Tip: Enable ORTO or hold Shift to constrain lines to horizontal/vertical.

3

Set the Reference

In the right panel, enter the real-world measurement of your reference line, choose the unit (mm, cm, m, or km), and click "Set Reference".

Alternative: If you know the scale ratio (e.g., 1:400), enter it in the 1:N field that appears after setting a reference.

4

Measure Away!

Now you can draw lines, polylines, and polygons to measure distances and areas. All measurements are calculated automatically and shown in the right panel.

  • Line: Measure straight distances
  • Polyline: Measure paths with multiple segments
  • Polygon: Measure areas and perimeters

Sidebar Tools Reference

Draw Tools

  • Select — Click objects to select, move, or inspect them.
  • Line — Click and drag to draw a straight line.
  • Polyline — Click to add points. Right-click or Esc to finish.
  • Polygon — Click to add vertices. Right-click or Esc to close. Requires a reference.

Edit Tools

  • Edit — Select an object first, then toggle edit mode to drag individual vertices.
  • ✕ Delete — Remove the selected measurement. Also works with Delete/Backspace key.

Viewport

  • Pan — Drag to move the canvas. Also works with Alt+drag or middle-click.
  • Zoom in/out buttons, or scroll wheel to zoom centered on cursor.
  • Fit to Window resets zoom and pan to default view.

Modes

  • Labels — Show/hide measurement values directly on lines.
  • SNAP — Snap cursor to dark pixels (lines) in the plan. Requires an image.
  • ORTO — Constrain drawing to horizontal or vertical only.

Color Picker

When a draw tool (Line, Polyline, or Polygon) is active, a color circle appears at the bottom of the sidebar. Click it to change the drawing color for that tool.

Common Use Cases

Construction & Architecture

Measure distances and areas from architectural plans, construction site photos, or building blueprints.

Land Surveying

Calculate land areas, plot boundaries, and distances from aerial imagery or survey maps.

Geographic Analysis

Measure distances between locations, calculate areas of regions, or analyze spatial relationships on maps.

Pro Tips

  • •Enable SNAP to automatically snap your cursor to dark pixels (lines) in the plan for precise placement
  • •Enable ORTO or hold Shift while drawing to constrain lines to horizontal/vertical
  • •Use Delete or Backspace to remove selected measurements
  • •Ctrl+Z / Ctrl+Y for undo/redo
  • •Toggle Labels to see measurement values directly on the canvas lines
  • •Right-click or press Esc to complete polygons and polylines
  • •Save your project from the right panel to continue later. Projects are stored in your browser.
  • •The status bar at the bottom provides contextual tips as you work

Keyboard Shortcuts

Ctrl+ZUndoCtrl+Y / Ctrl+Shift+ZRedoDelete / BackspaceDelete selected measurementEscComplete polygon/polylineShift (while drawing)Constrain to H/V (like ORTO)Alt + dragPan canvasMiddle mouse + dragPan canvasScroll wheelZoom in/out (centered on cursor)