Aerial Inspections – Roofs
Drones are a safer, cost-effective alternative to “Boots on the Roof” which can be dangerous and expensive especially for steep, high or fragile roofs.
Whether you want to see the big picture:
Or zoom it in the check on a specific area:
Or further in:
Whether it is a home or business, pictures tell the story better then words!
Aerial Photography and Processing
Flying a drone over land and taking a series of high resolution photos is just the first step of a longer process to turn those photos into something usable and useful.
First you take the hundreds of photos and run them through software — I use an open source package — WebODM which is a part of OpenDroneMap to create the the orthomosaic which is georeferenced and orthorectified as well as Digital Surface/ Terrain models and even 3D models.
Georectification is the process by which the remotely sensed raster image (the orthomosaic of images) is linked in to a coordinate system so that it can be accurately located onto a map.
Orthorectification is the process of removing the effects of tilt and terrain for the purpose of creating a “correct image” which depicts each pixel in the image as if it were collected from directly overhead or as close to this as possible.
The below orthomosiac was created by stitching together 160 images
Depending what is required, the picture might be all that is required, but further post processing needs to be applied.
Such as adding contours which uses the Digital Elevalation Model with further processing within a GIS system — I use QGIS which is another brilliant and powerful Open Source product.
Or creating a grey scale HillShade
Or a more colourful Digital Surface model
Or even a VARI vegetation index (which uses yet another post processing piece of software, in this case a Python script!). VARI is a measure of “how green” a normal RGB image. With the VARI algorithm applied it makes it possible to detect areas of crop stress in a field – the field below which is near Mannum is very stressed !