The Biodiversity Net Gain tool makes filling in the red line diagram easy. If you see warnings that the whole diagram hasn't been filled in, there are two steps you can take: see whether you can see the gap and fill it in or, failing that, expand the different habitat parcels.

On the list of Baseline Habitat Parcels, click + Add Another Parcel

Select one of the habitat types you have previously selected and then press Continue to go to the map screen.

On the map screen, look to see if you can find the area that hasn't been filled in ("the gap").

If you can see a gap, check to make sure that you have selected the right habitat type. If you need to select a different habitat type, press back to return to the habitat screen and select the right habitat and return.

Fill in the gap using the Auto Fill option.

Once you have drawn the new habitat parcel, click to return to the habitat list and see if you can continue. If you still get the warning that there are spaces, either repeat step one or - if you can't see any gaps - move on to step two.

If you are getting warnings that the total site area isn't filled in but you can't see where the gap is, it means you likely have a very tiny space between some of your habitat parcels and/or the red line. You can address this by simply expanding the habitat parcels on your site.

To do this, start by going to the baseline habitat list, select the largest parcel and press Continue to go straight to the map page

Once on the map page, turn off all snapping features.

Delete the habitat parcel. Then fill in the gap using the Autofill option. Press Continue and return to the Habitat Baseline list.

Press Continue to see if your red line is now complete If not, repeat step two, but delete and then autofill the second largest habitat parcel instead. Then try with the third and so on until the entire red line is filled in.