Using the Boundary Digitizer

You need to be logged-on to use the Boundary Digitizer. The page allows you to create polylines and polygons that define particular areas on a map.  These could be sites, nature reserves or areas of interest for example.  This page explains how to use this function.

Important Tips:

  • Before starting a new outline, navigate on the map to your area of interest and set the zoom to a sensible view.
  • Typically you would also wish to switch to the 'Satellite' view to use natural features as guides.
  • It is a good idea to very roughly outline your area first and then move (drag), add and delete points as needed at a more zoomed view.  It is much easier and quicker to adjust your line by editing rather than trying to place points accurately first time.
  • When not drawing points (after choosing to 'stop drawing') you can freely edit points by dragging them with your mouse.  Also, when you re-open an existing line it is immediately available for editing.
  • If you give your boundary a name which matches a site in our database, then the boundary will be shown in the relevant site account.


The top row of controls allow you to:

Choose an existing feature to edit from the drop down list.

start new line - will prompt you for a name for a new line or polygon.  You can then start to add points.  If you have unsaved changes to any existing work you will be warned.

reload line - re-loads the current line.  If you have unsaved changes to your line you will be warned.

delete line - will permanently remove the current line.  You will be prompted to confirm this action.

Map Area

Within the main map area you can zoom in or out using the + and - button at the top left.  You can switch between background views with the buttons at the top right.  Scroll the map by dragging it with your mouse down.

Current mouse position is reported in the cursor immediately below the map.  This shows National Grid and (Latitude, Longitude) in decimal degrees.

Edit Buttons

The row of buttons below the map provide the following edit functions:

undo last - will undo the last edit to your line (drag/move point, add point, delete point).

continue line - will continue your line from the last point drawn.  You can use this in conjunction with 'stop drawing' to continue work later.

stop drawing - will stop drawing mode and allow editing.  'Stop drawing' also cancels the add and delete point actions.

add point - allows you to add a new point anywhere on your line.  Note you need to click this button and then click the line where you wish to insert a new point.  You can then drag this point to any new position.  If you wish to cancel the 'add point' function click the 'stop drawing' button.

delete point - allows you to remove and existing point (or vertex) on your line.  Note you need to click this button and then click a point to remove it.  If you wish to cancel the 'delete point' function click the 'stop drawing' button.

close poly - completes the line by joining the last point to the first and renders as a filled polygon.  This also cancels drawing and puts the line in edit mode.

save changes - saves any outstanding changes.  When the current line is saved, information about the current map mode (Normal, Satellite or Hybrid) is also saved as your preferred drafting background.  Remember to save changes regularly and when done.

'view as polygon' Option

This option, situated below the edit buttons, will render your line as a closed and filled polygon.  You may wish to select this option prior to starting to digitize a new area if this is a closed shape.  You can change this view at any time.

If viewing as a polygon, you can click inside your shape and have the area reported by the map cursor (immediately below the map).  If not in polygon mode, you can click your line to have the length reported by the map cursor.  In either mode, you can click any point on to have information about that point displayed by the cursor.

'show other features' Option

By selecting this option you will see a list of all existing map features.  You can tick any of these to add them to your current map.  This is useful if drawing compartments within a site or when digitizing adjacent or segmented lines or areas.  You can remove a feature by un-ticking it.  De-select this option to remove all added features.

Overlays are always shown as outlines and your map settings (zoom, position and view) are unchanged.

Advanced Usage

You can refer to the digitizer with a calling subject using markup as follows:

[[page:Boundary Digitizer/s/line-name|alternative-text]]

Calling the page with a subject (/s/...) will open the digitizer with the named map feature ready for editing.  The alternative-text can be use to provide a friendly name for the page link like "edit this line".