Propeller Sales Engineer Kev Smith shares three ways you can use Terrain Editing to streamline the QA process for survey data on your site.
1. Quickly remove stockpiles and features for more accurate volumes
Use case: Calculating month-to-month volumes on a landfill
“For anyone working on a landfill site, covering the day’s work with a layer of dirt is a daily occurrence,” said Kev. “However, while every effort is made to push the layer of dirt off before work starts again the following day, the extra layers of material added to your cells will lead to inaccurate numbers when it comes to calculating monthly volumes for progress reporting.”
The usual process to correct this inaccuracy involves measuring the volume of the pile of dirt used to cover the cell, entering it into a spreadsheet and then manually subtracting it from the total volume at the end of the month.
Terrain Editing allows you to quickly draw around the stockpile and edit it out of your terrain model, instantly removing it from the final monthly calculation. “This simple process not only saves time, but also leads to more accurate quantities and monthly reports you can trust,” noted Kev.
2. Use Smart Filtering and Terrain Editing together
Terrain editing makes it very easy to customize your terrain model so you can generate more accurate measurements.
“Propeller’s Smart Filtering does some of the heavy lifting when it comes to removing features and objects such as equipment, vegetation, and buildings, but if you choose to use the strongest filter it can remove things you don’t want it to.”
Terrain Editing gives you the opportunity to refine your terrain models with more precision. You can choose a lighter filter, such as Equipment, and zoom in on the features to manually remove anything that has been left behind after the filter has been applied.
“I’d still recommend to anyone doing earthworks that they still use the Equipment filter because it does a really good job of removing inaccuracies and features in a time efficient way. Once you’ve done this, you can then go in and refine your model using Terrain Editing.”
“It just gives you more control and confidence, especially when you’re sharing the data with project managers. You can be confident that you’re sharing good and consistent data, while still maintaining control for that portion of the process,” said Kev.
Learn more about Smart Filtering here.
3. “Clean up” areas of your terrain model that just don’t look right
Use case: bodies of water
Bodies of water on site are notoriously hard to map by photogrammetry due to the constantly changing surface and reflection of light. Because of this you end up with high peaks and low troughs in your surface that are impossible to avoid. However, using Terrain Editing, you can quickly create a boundary around your water using the Polygon Tool. Once applied, this will flatten the entire surface, making it look more accurate to the real-life terrain.
“If you work with anyone who isn’t familiar with photogrammetry, being able to edit out these areas can play a big role in helping you improve the perception of how trustworthy your survey data is,” said Kev. “Anyone who sees waves that are 10ft tall and deep troughs will often mistrust what they are looking at and it can raise questions around the accuracy of the data.”
Use Case: Trees and vegetation
Another great example of how Terrain Editing can be used is to remove trees or areas of vegetation affecting the accuracy of your volume measurements. By dropping the elevation of the Terrain Edit below the existing ground, obstacles like vegetation overgrowing a bench can be removed, allowing bench volumes to be measured without taking the vegetation in account.
“I did two test flights the other day, one at 80m and again at 50m. The flights were done straight after each other and processed separately. The ground surface was really consistent across both surveys, but when I came to calculate the volume of the area there was huge variation between the two.
“It was because of an area of trees. Trees move in the wind, and this change between the two surveys caused large discrepancy in the volume calculated. You can use Terrain Editing to completely flatten the area of trees on both surveys to generate a more accurate measurement.”
Kev leaves us with a final tip: “Don’t forget though, if you are removing something and want to compare like for like then you need to make a terrain on both surveys.”
For a step-by-step guide to using Terrain Editing use this article here.