Mapping a Disused Coal Plant for New Life

Coal is falling out of favour, resulting in power plant closures. Mapping is a first step in the site redevelopment process, but data collection can be tricky. UAV mapping has proven to be a good solution to overcome the challenges of capturing geospatial data in challenging environments.

As many countries transition away from fossil fuels, coal power stations are being decommissioned across the globe. These coal power plant closures leave huge infrastructures behind, including tall chimneys and cooling towers. Eventually, the land they sit on may be repurposed for more attractive and functional alternatives to empty coal power plants. This can lead to interesting but complicatedcontrolled demolition projectsto bring down the towers. Mapping a disused coal power station is a first step in the redevelopment process, but it is not always a simple task, as H&W Surveying and Consulting discovered.

H&W Surveying and Consultingis a company whose core services are in building and quantity surveying. They also assist with insurance claim assessment for fires and floods amongst other events. Their repertoire of projects currently includes mapping sea walls, harbours and complex roofs to generate dense point clouds. Keith Wakeley, who kindly shared this project, is a veteran ofPix4D software, benefiting from theextensive support available onlineas well as the社区论坛which have helped him develop his expertise. This meant he was well-equipped to work with Pix4Dmatic on this project.

For this shutdown coal power plant, H&W Surveying and Consulting were principally interested in assessing an ash stockpile on the eastern side of the site, as well as creating a point cloud of the rest of the coal station. The location of this power plant is on the flood plain of the River Trent, making it vulnerable to flooding. H&W Surveying and Consulting’s client hoped to use the ash stockpile to help fill in trenches in the land and protect the terrain beneath the power plant from the river flooding. However, this would not be possible if the stockpile had been static for too long and filled with organic matter. Whilst H&W Surveying gathered aerial data, geotechnical specialists sampled bore holes to assess the ash pile to determine if it could be moved, and completed an ecological survey.

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There are strict regulations for flying drones in the UK to maintain air traffic safety. H&W Surveying and Consulting got permission for their flight from the relevant authorities, but were faced with a problem: they were allowed to fly at 120 metres (394 feet), as per UK restrictions, but the cooling towers on site were 115 metres (377 feet) tall and the main chimney was 220 metres (721 feet) tall. Wakeley’s team flew around these in an orbital manner up to the legal height restrictions. For this reason, the use of a rotary drone with manoeuverability options around the tower was ideal. Grid missions were then flown in chunks between the cooling towers at a height of 75 metres (246 feet) to collect data.

The vertical size of the site was not the only obstacle to the project. Spread across 171 hectares (423 acres), Wakeley had to spend the first day on site setting up the ground control points (GCPs), which are important forimproving the accuracy of the data进行处理。80 gcp Wakeley明显site, using his expertise to determine their best locations. He then split the project into 16 flights. The large number of flights necessary because of the obstructions around the site, ranging from buildings and infrastructure to the tall cooling towers. Planning adrone inspection flight properlycan save time during data collection. In the end, each flight collected up to 500 images, generating a large total dataset of 4,004 images.

灰分库存也是一个问题：土地可能不稳定，或者对于客户的计划而言太牢固。它容易受到附近河流的洪水泛滥，散布库存的内容可能会减轻该地点对未来发展的脆弱性。仔细管理这些库存旨在防止过多的有机积累，这可以防止建筑计划。如果库存有很多动物洞穴和栖息地，则在运输或使用此事方面存在更严格的规则。这就是为什么需要将H＆W测量和咨询公司进行的数量评估与孔洞和生态调查数据相结合的原因，以完整地了解Ash Stockpile州的状态。沃克利（Wakeley）必须与现场其他团队进行协调，以清楚地看到他飞过它时的灰烬。

Mapping large projects 3x faster

Wakeley加载图像到Pix4Dmatic dekstop computer, and marked 80 GCPs before running Step 1 of processing.

Pix4Dmatic is built for crunching large datasets, even ones over 10,000 images. When H&W Surveying and Consulting ran their data in other photogrammetry software, Step 1 took 9 hours and 47 minutes, whereas Pix4Dmatic needed just 2 hours and 52 minutes. The scale up in speed is undeniable, and H&W Surveying and Consulting were very impressed.

Pix4Dmatic’s workflow was also simple and seamless. Wakeley found it quick to pick up, with an intuitive set up that suited his style of work. In addition, the GCP picker helped speed up his work whilst the processing options were ideal for his project.

Looking to the future

The final output was a dense point cloud used alongside cross sections from the terrestrial surveying and boreholes, and cross-referenced with grid lines across the site. The client could then plan the next stages of the redevelopment project, paving the way for the disused power station to be put to better use.

Similarly, Wakeley found that usingPix4Dmaticwas a new experience opening up new avenues for larger projects. This large dataset didn’t need to be broken down into small, manageable chunks and instead crunched all 4,004 images without issue. For a surveying company with the range of projects that H&W Surveying faces, Pix4Dmatic is an exciting addition to their photogrammetry toolkit unlocking new possibilities to help contribute to a positive trend in society – the move away from fossil fuels to greener alternatives, freeing up huge infrastructures to be repurposed as part of a better future.