And now something completely different – surveying a shooting range in South Africa
One of our clients, CDJ Land surveyors, was asked to measure out a shooting range as accurately as possible. This was due to the shooters of the range complaining that the ground was not level enough, and that they could not see the targets at the end of the range due to the uneven surface.
On the terrain there were a number of high and low points that they could not miss. They did not want to risk it by measuring using the old conventional way due to the fact that they might miss a few critical high and low points which would be crucial. They opted to make an accurate representation of the ground in the form of a 3D model. This was in order for the shooting range to run the simulations needed to see how they could create the best shooting environment for the shooters.
To do the survey they had to keep the following information in mind:
According to South African national standards, an outdoor no danger range shall be constructed or designed in such a way that no misdirected shot, that can reasonably be expected to be fired towards the targets, will leave the range.
They needed to identify the outdoor danger area ranges. These are ranges where the stop butt (only outdoor ranges have danger areas) is not sufficiently high and/or wide enough to meet the requirement to contain all reasonably expected misdirected shots. Outdoor danger area ranges shall therefore have a danger area that extends beyond the stop butt. In the case of shotgun ranges there is no stop butt, and the danger area then naturally is the area where all the shot impacts.
A stop butt (or backstop) refers to a bank, wall or other device, behind and around the bullet trap, intended to stop all misdirected shots that can reasonably
be expected to be fired.
RANGES SAFETY AREAS is what they needed to keep in mind.
The safety area for an outdoor range is defined as the downrange area (forward of the firing point) that is designed to contain bullets that pass over, or beyond, the backstop under specified conditions. These bullets can be the result of high angle shots (overshoots) or bullets that ricochet off targets, the backstop and other range surfaces (e.g. the range floor). Safety areas are very important considerations in outdoor range design; however, they are concerned strictly with ballistic issues and do not address the issue of noise pollution.
Equipment used for surveying
With all this information they knew they needed to be spot on with their surveying, and decided to use the following equipment.
In order to do this they first needed an accurate plan to recreate the environment. They used the following tools to conduct the survey:
- SOM Reach RS2 Complete surveying kit
- Phantom 3 Pro
- 3Dsurvey Software
- GCP targets.
Based on this equipment they could get the following dataset:
In this image we could clearly see the positioning of their GCP’s as well as their flight grid. They did a double grid over the area to ensure they did not miss any areas with insufficient overlap. The side grid was used for processing while the rest was removed.
Based on their GCP points they could typically expect the following accuracy in the survey which met their requirements:
They processed the job and were able to see the following results:
A very nice and accurate top view and shooters view with the end bank in clear sight.
Clearer view of the bank from shooters position.
Another image of the high wall in more detail.
A view back to the shooters position.
A good height map of the area:
What we could see from this height map is that the light blue indicates low points on the site. We notice that there are a few places down the range that are in fact higher and also lower that the shooters position. They would need to eliminate the high and low points of the terrain to give the shooter the best ability to make an accurate shot; being able to see all the surroundings and places on the retain.
We can see that close to the target area is a darker green which means that it is higher, and then after that there is a light blue meaning lower again.
So this would mean that the shooter might potentially not have the ability to see the target at the furthest point of the sight.
Example of what needs to be eliminated:
The equipment used was able to point out this information to the client, and as a result they are now able to make alterations to the range to make it a world class shooting range.
Author: SOM Survey Instruments 2022