Get a human review of your red line!
Get a member of our team to review your red line diagram to make sure all are drawn accurately (please note that this may take up to two working days)
On this page, you need to draw the redline boundary of your site. This is the total perimeter of your site and should be the same as the red line that you provided on other parts of your application.
A finished red line diagram should look something like this:
Please note that the red line is a simple perimeter of the site, there are no red lines within the red line perimeter.
How to use this page
1) When you arrive on this page, you will see a map of the location you previously identified your site being on.
2) You should draw the red line boundary of your site using either the Select OS Features option (automatically selected) or the Draw option.
At the bottom of the page is a information box (next to to the undo and redo button) letting you know what the tools you have selected do.
Important point: Make sure you have a simple boundary and no 'red line within the red line'
You should make sure that there are no red lines within your red line diagram. For example, this site has a red line within it:
You should, instead, click on the house inside so that it is also selected within the red line and look like this:
Once you are done, press Continue at the bottom of the page to proceed.
Error Information: Unfortunately, your site area makes you a 'Large Site'
When you hit "continue" you might see a box appear saying "Unfortunately, your site area makes you a 'Large Site' Your site area exceeds the maximum permitted for the Small Site Metric"
The Biodiversity Net Gain Tool is currently designed for people who are eligible to use the "Small Site Metric". This means that only the following can use the tool:
If you are building a residential development and don't know how many residential units you are building. Under the laws set out by the Government, we can only accept a red line diagram that is under 5,000m² if there are an unknown number of residential dwellings being built.
For all other types of development. Under the laws set out by the Government, we can only accept a red line diagram that is under 10,000m².
You will need to commission a suitably qualified ecologist to complete the full statutory metric calculator. You may also wish to contact CIEEM to find a suitably qualified ecologist.
We will be releasing a new tool for larger sites soon. You can register your interest here.
You will be able to either return to the project page or, if you think there has been a mistake, you can revise the red line and readjust the size. If you get the size below the thresholds, you will be able to proceed.
Error Information: Self Intersecting Polygons are not allowed
This happens when you draw a red line diagram that intersects itself. These sorts of diagrams are not permitted under the rules.
Suggested steps
Try and use the Select OS Features to see if you can draw the site easily
If that doesn't work, then try and draw a basic shape with the draw tool which roughly aligns with the area. Then use the Edit tool to amend it to reflect your site's perimeter. There will not an error if you are in edit mode.
Tools on the page
At the top of the page you should see four options:
Draw
Select OS Features.
Edit
Delete
In the top left of the screen you will see a zoom tool.
In the top right of the screen, you will see a scale
At the bottom of the screen, you will see Undo and Redo tools.
In the right of the screen you will see Advanced Tools, with six options:
Angular Snapping
Map Features
Building Guides
Opacity
Edit / Adjust Plans
Upload Plans
How to use the tools on the page
You can tell a tool is active because it will be highlighted in yellow. You should click on the button a second time to turn off the tool.
Basic tools
Draw: This will allow you to draw a polygon onto the map. When this mode is on you will see a blue circle under your cursor.
Click on the map to start drawing. You will see a blue dot be placed on the map.
Now drag the map in any direction to create a length. As you do so, you will see the size of the length next to the line you are drawing. Simply click to create a corner.
One you have created two or more corners, the area will also be displayed.
Simply click on the blue dot to complete the polygon.
Select OS Features: Will automatically be selected. When this mode is on, if you move the mouse cursor over a part of the map, part of the map will automatically be highlighted in red. This is based on preexisting information, and may either select your whole site or part of the site. Simply clicking anywhere on the highlighted parcel will result in it being selected (you will see the red line become thick). You can adjust this red line by either going to edit mode, or - if you move the cursor over an adjacent parcel - you will be able to expand by clicking on this parcel. Please note, if you click on a area that is not adjacent, you will start a new red line diagram.
Edit: When this mode is selected, you will see the following information appear:
White Boxes. These are all the corners on your red line diagram.
You can click and drag these boxes to adjust the shape of the red line diagram.
If you click once you will delete the white box (if you do this by accident you can simply hit Undo at the bottom of the page.
Grey Boxes. If you click on one of these it will turn into a white box.
Angles. Each white corner will have the angle of the corner. As you adjust it you will see this angle change.
Lengths. Each length will have a length in metres.
Delete: When this mode is on, simply click on the red line to delete it.
Undo: Click on this button to undo your last action.
Redo: Click on this button to redo your last action.
Advanced tools
Angular Snapping: When you tick this option, you will be able to select an angle
5°
10°
45°
90°
When you select one of these options, when you are using the draw tool, you will always 'snap' to this angle or a multiple of it (e.g. if you select 5°, you will only be able to draw at a 5°, 10°, 15°, 20°... etc angle).
Map Features: When you tick this option, your cursor will automatically "snap" to preexisting map features (e.g. a road, or a site boundary, or feature). This can help to create a very accurate red line diagram.
Building Guides: If you have uploaded a site plan (see below) you can click on the eye icon to show or hide this plan.
Opacity: If you have uploaded a site plan (see below) you can use the scale here to make the site plan more or less transparent.
Edit / Adjust Plans: When this mode is selected, you will be able to:
Move the site plan by clicking and holding on the image and then dragging it to a new location.
Change the size of the site plan by clicking and dragging the corners
Spin the site plan by clicking and holding the black dot that hovers over the top part of the diagram
Delete the site plan by clicking on the delete icon in the white circule.
Upload Plans: When you click this you will open a window that will allow you to upload your site plan.
You should use the top left hand box (in grey) to upload your site plan (you can either click on the "Browse Files" to select the file from your computer or you can drag the image into your grey box). When selected, you can preview the image and then click Save Files to upload it to your site.
Please note that, if you upload a pdf, you will need to select the right page. To do this:
Upload the pdf by dragging it onto the box on the top left hand side of the grey box
The pdf will appear below the upload box (i.e. in the bottom left hand side). Please click on this pdf file name.
You will see page numbers appear at the bottom. It should look like this:
Using the arrow buttons, move across to the page that has your site plan on it. Then press Add Page