Drawing polygons · Measure Map Online Help

Measure an area by outlining it on the map, then read its area and perimeter, name it, describe it and cut holes in it.

A polygon is a closed outline you draw on the map, corner by corner. Measure Map works out its area and perimeter as you draw, and keeps them up to date whenever the shape changes. Use it for fields, plots, roofs, lawns, car parks or anything else with a surface.

A field outlined as a polygon, with its name and area on its label

Draw a polygon#

Open a project. In the top toolbar, open the Crosshair mode button and choose Polygon.
Check that the magic button, at the bottom right of the map, shows Add. It does when you open a project.
Hold Shift. The crosshair appears under the mouse.
Click at each corner of the area, in order around it. The first click starts a new polygon; each click after it adds a corner.
Let go of Shift to stop adding corners, and hold it again to carry on.

While you draw, the first corner's pin is green, the last one purple and the others red. A line runs from the last corner to the crosshair, and the crosshair shows how far it is from that corner and in which direction, in degrees from north.

Instead of holding Shift, you can right-click the map to turn the crosshair on, and right-click again to turn it off. On a touch screen, use the always-on crosshair: see on a touch screen.

A polygon being drawn: the green first pin, red pins, the purple last pin and the line to the crosshair

Finish and lock the polygon#

When the last corner is in place, lock the polygon. Either:

press Lock polygon in the bottom toolbar, which is there while you are drawing, or
click the round lock button in the middle of the polygon. It appears once the polygon has three corners. To hide it, turn off Show the lock button while drawing in the project's Settings, under Map settings.

The Lock polygon window opens:

Type a name in Polygon name, or keep the one it was given, such as "Polygon 3". Polygons, lines, circles, rectangles and spots are each numbered on their own.
Leave Close polygon on. It adds a last corner on top of the first, so the outline is closed and the perimeter includes the closing side. The switch is there only when the polygon has three corners or more.
Press Lock.

The polygon gets its label, with its name and area, and the next click with the crosshair starts a new shape. Cancel closes the window and lets you go on drawing the same polygon.

A locked polygon no longer grows as you click, and the magic button's Move tool moves it as a whole. To change its outline later, unlock it: see locking and unlocking.

The Lock Polygon window, with the polygon's name and the Close polygon switch

Read the area and perimeter#

The measurements box at the top left of the map shows:

a: and p:, the area and perimeter of the polygon you are drawing, updated with every corner;
Σa: and Σp:, the total area and perimeter of the project's polygons. A hole is taken off its polygon's area, and its outline is not added to the perimeter;
Σd:, the total length of the project's lines.

When you draw on a slope in the 3D view, the box also shows 3D a:, 3D p: and the slope, ∠: see along the slope.

Once a polygon is locked, its label on the map shows its area (to begin with), and its panel shows both. To add the perimeter to the label, turn on Show perimeter in its panel: see choose what the label shows.

Areas and lengths are calculated on the WGS 84 ellipsoid, the model of the Earth that GPS uses, not on the flat picture of the map, so they stay right at any size and latitude. They are shown in the units chosen in the project's settings (metric, imperial or local units), and switch to the larger unit as they grow, from m² to km² for example. See measurement units to change the units, or settings to hide the box with Show total measurements box.

The measurements box with the area and perimeter of the polygon being drawn and the project totals

The polygon's panel#

Click a polygon's outline, fill or label to open its panel on the left. You can also press next to it in the Geometries list of the top toolbar (see the Geometries list), or click near its label with the Info tool of the magic button.

From the top, the panel holds:

The name. Click it to rename the polygon.
A small map of the polygon.
Pts (its number of corners, not shown for a circle; press it to open the first corner: see the point's panel), Perimeter and Area, and under them the same measured along the slope.
Estimate and Products, once you have products: put one or several products on the polygon, and the estimate is what they cost on it. See estimates.
Holes, when it has any (see below).
The actions, and the red Remove button, which deletes the polygon and its holes after you confirm.
Description: press , write up to 500 characters, and press .
Colours, Geometry type, Appearance and Visibility: how the polygon looks and what its label says. See colours, lines and labels.
Photos: the polygon's pictures, and those attached to its corners.
Copy link: copies a link that opens the project with this panel open, for anyone who has access to the project.

Action	What it does
Unlock / Lock	Unlocks the polygon so you can change it, or locks it again: see editing shapes
Elevation profile	Charts the height of the ground along the outline (below)
Grid	Lays a grid of cells over the area: see grids
Split and Join	Cut the polygon in two, or merge it with one it overlaps: see editing shapes
Subtract	Takes off the ground another polygon covers: see editing shapes
Buffer	Draws a zone at a set distance around it or inside it, which follows it when you edit it: see buffers
Attach picture	Adds a photo to it: see pictures
Duplicate	Makes a copy beside it: see editing shapes
Rotate	Turns it: see editing shapes

People who can only view the project see the figures, but not the actions. A polygon made from a cadastral parcel also shows a picture of the place and Cadastre info, which opens the registry's page (see cadastral parcels). While the 3D map is on, a 3D view card sets where the polygon is drawn, under Height: On buildings, On the ground or At a fixed height. Raise or lower (m) moves it, its pins and its labels up or down together, for a polygon that floats above a roof or sinks into it, and Raise shapes into solids raises it into a solid.

The polygon panel: name, small map, measurements, actions and the styling cards

Along the slope#

On a slope, such as a roof face or a field on a hillside, the real surface is larger than its outline on the flat map. Under the flat figures, the panel gives the polygon measured along the slope: 3D perimeter, 3D area and Slope, in degrees (with imperial units, also as a roof pitch, such as 6/12). A line gets its 3D length. Circles are not measured this way.

A roof face's panel: its flat figures and, under them, the 3D perimeter, 3D area and slope

Each corner's height is the height you clicked in the 3D view or, for a corner drawn on the flat map, the ground's height there, which the panel looks up when you open it. The 3D area is worked out on one flat plane through the corners, so it is exact for one roof face at a time: draw each face as its own polygon. An outline around a whole roof, with its corners at the eaves, measures only the footprint.

The label on the map, the project totals and estimates use the flat figures.

Elevation profile#

Press Elevation profile to chart the height of the ground along the outline, from the first corner round to the last: height up the side and distance along the outline across the bottom, both in your units. Move the mouse along the chart: a marker on the small map at the top of the panel shows where each height is.

Cut a hole#

To leave part of an area out, such as a pond in a field or a courtyard in a roof, draw it as a polygon inside the first one and lock it. Measure Map sees that it lies inside another polygon and opens Inner polygon, asking whether it is a hole. Press Yes, then name and lock it as usual.

A hole:

is taken off the outer polygon's area; the outer perimeter does not change;
is drawn without a fill, and is not counted in the project's total area;
loses its products: a hole is never priced;
is listed under Holes in the outer polygon's panel: click it to open the hole's own panel;
moves, turns, is copied and is deleted with the outer polygon.

Hole labels can be hidden on their own with Hole labels in Show/Hide elements in the bottom toolbar. Answer No to keep the inner polygon as a separate area.

A field with a pond cut out as a hole, and the Holes list in the field's panel

Circles and rectangles#

The magic button also draws exact circles and rectangles, which are measured like any polygon:

Circle: click the centre, move the crosshair to set the radius, and click again.
Rectangle: click two corners to set one side, move the crosshair to set the width, and click again.

The Lock polygon window then opens to name the shape. See the magic button.

When others draw too#

In a shared project, everyone who can edit it draws at the same time, and each person's shapes appear on everyone's map as they are drawn. A polygon someone else is still drawing shows their photo in the middle until they lock it. See work together.