Now, let�s talk about the best practices for marking the GCP targets:
Choose your GCP target colour based on the background colour you have a the site.
The colours of the GCP target should strongly contrast with the background.
Usually, white tends to be the best colour unless you have a very light coloured background.
The GCP should be a semi permanent or permanent feature and placed on flat terrain.
It should not move or be moved once placed and captured.
The most ideal size and shape of the GCP target is a 1 meter by 1 meter �X�, marked on the ground.
Number each target so that you can identify them later to assign the coordinates during the processing stage.
If there are already some well positioned and prominent markings at the site like arrows,
use the tip of the arrow as your target.
This will save you a considerable amount of time and effort in painting a new target.
Do not mark GCPs below obstructions like trees.
There are various options you can use for GCP targets, depending on the surface on which you need to mark them:
Spray paint is suitable for tar and concrete surfaces
Regular liquid paint is also suitable for tar and concrete surfaces
Ceramic tiles painted or arranged in this fashion is suitable for surfaces where you don�t want to leave a permanent mark
Lime whitewash works on all kinds of surfaces and can be washed off easily
So now, we�re all set to go to the site and start the drone mapping process!
Do make sure you run through your checklist before you go to the site
I have explained the checklist items as well as the entire flight execution process in detail in part 1 of our course series.
Let�s go through the workflow we have followed for one of our projects using GCPs.