3D satellite photo showing some of the 775 ground survey points

PhotoSat publishes 21 new satellite surveying accuracy studies

3D satellite photo showing some of the 775 ground survey points

3D WorldView-2 satellite photo of Asmara, Eritrea, showing some of the 775 ground survey points that determine the 14cm PhotoSat surveying accuracy.

21 PhotoSat surveying accuracy studies from seven different stereo satellites

PhotoSat has published 21 new satellite surveying and mapping accuracy studies, now available on our website. The studies include data from seven different stereo satellite systems. The best results show elevation surveying accuracies of better than 15cm.

The accuracy studies include stereo satellite data from the following satellites:

  • WorldView-1
  • WorldView-2
  • WorldView-3
  • Pleiades-1B
  • KOMPSAT-3A
  • SPOT-7
  • ALOS PRISM

 

PhotoSat has measured accuracy on over 750 stereo satellite surveying projects

PhotoSat has delivered over 750 satellite surveying projects since 2007 and we have carried out accuracy evaluations on the majority of them. Most of the survey data on these projects belongs to our customers and cannot be shared publically; however, customers have provided feedback on many of these projects.

The results of these 21 new accuracy studies are consistent with our project accuracy evaluations and customer feedback.

 

PhotoSat accuracy test areas in Eritrea and California

The accuracy studies were conducted over two test areas. One test area is west of Asmara, Eritrea where PhotoSat has access to more than 45,000 ground survey points over a 50km by 20km block.

The second area is in SE California where PhotoSat uses a very accurate Opentopography.org open source LiDAR survey.

 

The effect of different numbers of ground survey points

The studies employed different numbers of ground survey control points for each test area and each satellite system. For some of the satellite stereo pairs the accuracy is significantly improved by increasing the number of ground survey control points.

For example, the WorldView-2 survey for Eritrea is accurate to 19cm in elevation with two ground control survey points, and accurate to 14cm in elevation with 21 ground control points.

In contrast, the accuracy of the WorldView-3 survey for the California test area is not improved by additional ground survey points. This WorldView-3 survey is accurate to 13cm in elevation with one ground survey control point and with 153 ground survey control points.

 

PhotoSat has been continuously producing satellite accuracy studies since 2007

In order to provide objective quantifiable accuracy data for stereo satellite surveying and mapping, PhotoSat has been continuously producing accuracy studies since 2007. We have previously published nine of these studies. The rest of the studies were used for calibrating and improving our processes.

 

21 new accuracy studies all processed with the same version of the PhotoSat processing system

The 21 new accuracy studies were produced with the most recent version (2016) of the PhotoSat processing system. Where possible we used satellite data produced by the 2015 or 2016 versions of the satellite operators’ ground processing systems.

 

Summary of PhotoSat 2016 accuracy study results

Satellite Test area km² GCP RMSE
WorldView-3 California 150 1 13cm
WorldView-3 California 146 153 13cm
WorldView-3 Eritrea 100 21 15cm
WorldView-2 California 173 1 15cm
WorldView-2 California 173 153 12cm
WorldView-2 Eritrea 100 21 14cm
WorldView-1 California 174 153 14cm
WorldView-3 Eritrea 198 2 19cm
WorldView-2 Eritrea 400 2 19cm
WorldView-1 Eritrea 100 21 19cm
WorldView-1 California 174 1 23cm
WorldView-1 Eritrea 420 9 23cm
Kompsat-3A California 144 14 21cm
Pleiades-1B Eritrea 189 74 26cm
Pleiades-1B Eritrea 189 1 28cm
Kompsat-3A California 144 1 50cm
Kompsat-3A Eritrea 130 11 48cm
Kompsat-3A Eritrea 130 1 53cm
SPOT 7 Eritrea 1,458 1 4m
ALOS PRISM Eritrea 2,300 3 2m
ALOS PRISM Eritrea 2,300 1 4m

See PhotoSat’s accuracy studies overview for full details.

For more information about PhotSat’s surveying accuracy, please see our satellite surveying case histories or visit the following links.

Satellite surveying

How can modern satellites photos possibly be accurate to 20 centimeters in 10 kilometers?

By Gerry Mitchell, P.Geo, President PhotoSat

ground control survey points in eritrea test area

3D WorldView-1 satellite view showing the ground survey points in PhotoSat’s Eritrea test area.

 

My intuition rebels at the notion that a satellite orbiting 750 kilometers above the earth, traveling at 7 kilometers per second, could possibly take photos of the ground accurate to 20 centimeters in 10 kilometers. When you take into consideration that these satellites have scanning cameras which take their photos like push brooms, with the north end of the photo taken a few milliseconds before or after the south end, and that the whole satellite is vibrating while the photos are taken, it boggles the mind. It just does not seem that such high accuracy should be possible. However, the satellite photos themselves, checked with tens of thousands of ground survey points, clearly demonstrate that the accuracy is real.

How do the satellites and cameras work?

We engineers and geoscientists in the commercial realm don’t actually know how these satellites and cameras work. Almost all of the technical details of the imaging satellites, their cameras, and their ground processing stations is classified. Or if it’s not classified it’s certainly very difficult to discover. I’ve had many conversations with satellite engineers who seem like they’d love to tell me why their satellites perform so amazingly well. Sadly, they simply aren’t allowed to discuss classified technology with anyone without the proper security clearances.

Whenever I have one of these conversations, it always seems to me that part of what the engineer knows is public and part is classified, but the engineer cannot be sure that he or she can remember what is still classified and what isn’t so it’s safest to say nothing. I’ve had satellite engineers decline to confirm information that is published on their own company’s website. Needless to say, this can make for some very awkward conversations.

We engineers and geoscientists in the commercial world only have access to the satellite photos themselves, and very general public information about the satellites and their cameras.

How accurate are the satellite photos?

When the Digital Globe WorldView-1 (WV1) satellite photos first became commercially available in 2008, PhotoSat acquired stereo photos for a test area in Eritrea where we have over 45,000 precisely surveyed ground points. When we shifted the WV1 photos 3m horizontally to match any survey point, we were amazed to discover that all of the survey points within 10km matched the satellite photos to within 20cm. We eventually documented this discovery in an accuracy study white paper that is now published on our website.

Now, eight years after that initial WorldView-1 accuracy study of the Eritrea test area, we have processed hundreds of satellite photos from the WorldView, Pleiades, SPOT and KOMPSAT satellites and have come to expect this incredible accuracy. I’m still in awe that this is possible and I still don’t know how it is achieved. I do know that the photos are amazingly accurate.

black and white photo of over 15000 ground survey points in PhotoSat Test Area

WorldView-1 satellite photo over the PhotoSat test area in Eritrea. The over 15,000 ground survey points used to confirm that the satellite photo accuracy is better than 20cm in 10km are shown as black dots. The completely black areas are survey points every 20m along lines separated by 100m.

 

 Colour image of a one meter PhotoSat survey grid produced from the WorldView-1 satellite photos

Colour image of a 1m PhotoSat survey grid produced from the WorldView-1 satellite photos. The ground survey points demonstrate that the PhotoSat grid is accurate to 35cm in elevation.

 

 

PhotoSat 1m elevation image of a tailings beach, with 15cm vertical accuracy

The Challenge of Mine Tailings Beaches and Elevation Mapping

Mine tailings beaches are notoriously difficult to monitor. They’re the hardest surveying task at a mine. Data needs to be up to date, but tailings ponds can be huge: Suncor’s tailings ponds cover over 30 square kilometers. Ground survey teams can’t get close enough for safety reasons, and aerial LiDAR data delivery can be frustratingly slow. Low-flying drones are challenged by cold weather, and cannot cover much distance in a day, so are not reliable when measurements are required for a larger area on the same day.

That’s the challenge Suncor faced at its Alberta oil sands mine. Surveying Suncor’s Tailings Reduction Operation (TRO) site meant getting accurate data quickly over a mine site covering over 270 square kilometers. And when Suncor tried using traditional GPS, they found that only about 20% of the site was safe for crews to access. The next step was to try 3D laser scanners, but these simply couldn’t produce enough data fast enough; multiple set-ups were required and yielded sparse data that required significant processing to be comprehensible and usable. This meant adding to an already too-long wait time, as well as additional expense.

Elevation mapping solutions

PhotoSat’s 15cm accuracy satellite topography (DEM) addresses the challenge. Because we use high accuracy satellites, the data is collected safely and easily, reducing the need for ground crews to expose themselves to hazards. And we can collect satellite photos anywhere in the world, making them ideal for remote or challenging terrain.

50cm satellite ortho photo

50cm resolution satellite ortho photo of a tailings beach. © DigitalGlobe 2013

 

PhotoSat elevation image of a tailings beach

PhotoSat 1m elevation image of a tailings beach, with 15cm vertical accuracy

 

Once the satellite imagery has been acquired, we run it through our unique processing system, developed for the industry by us from seismic data processing tools, with engineers in mind.

We have proven the accuracy of our elevation mapping using tens of thousands of ground control points as comparison. Numerous proof of accuracy studies are available on our website.

We map the entire Suncor site every two weeks, providing usable elevation surveys only five days after data acquisition for use in Suncor’s bi-weekly engineering meetings. Our satellite mapping provides an instantaneous snapshot of the entire tailings beach waterline, the geometry of the beaches, and the height of the tailings dykes. We continue to map the Suncor Millennium and Steepbank mines every two weeks, including mapping the Mature Fine Tailings cells in thickness increments of 15cm.

The digital elevation models are also used for mapping windrows, monitoring tailings dykes, calculating volume changes, and verifying the locations of as-built infrastructure. When Suncor’s tailings engineers need to make a decision, they have the reliable, up-to-date data to base it on.

The original presentation made my Suncor at the 2014 Trimble conference that compares PhotoSat mapping to alternatives, can be viewed here.

To learn more or get a quote for topographic mapping for your resource project, contact us at info@photosat.ca or 1-604-681-9770.

50cm satellite ortho photo

Alberta to Ease Tailings Regulations

Alberta has announced that it is easing up on tailings regulations, as several mine operators in the region are asking for reduced regulatory pressure. It’s a move away from the regulations, known as Directive 74, that have governed Alberta oil sands for the last six years.

Directive 74 required mining companies to ‘reduce tailings and provide target dates for closure and reclamation of ponds,’ and to report to the industry watchdog on their progress. But the industry has failed to meet the requirements of the legislation – and the Energy Resources Conservation Board (ERCB) watchdog stopped enforcing them in 2013, the last time a company was punished for not hitting its cleanup targets.

Parker Hogan, a spokesman for Kyle Fawcett, the Alberta Environment and Sustainable Resource Development Minister, said, ‘What we have heard is that despite the best efforts and significant investments, companies have had significant challenges to achieve the requirements that are in Directive 74.’

Since then, the ERCB has been replaced by a new regulatory body, the Alberta Energy Regulator (AER), and Directive 74 has been replaced by the Tailings Management Framework (TMF), a new regulatory structure with different aims. (The new framework is accompanied by strict groundwater use rules.)

The key change has been to refocus efforts on growing industry sustainably rather than directly on reducing tailings ponds. The new regulations give industry more leeway in some areas, allowing them to slow the growth of tailings ponds rather than working to actually reduce them; but they also promise new restrictions in other areas.

Kyle Fawcett laid out in more detail the requirements of TMF:

  • limit the amount of tailings that can be accumulated,
  • push companies to invest in technology to reduce tailings
  • establish thresholds to identify when companies must act to prevent harm to the environment
  • require companies to post financial security to deal with potential remediation issues and
  • ensure tailings are treated and reclaimed throughout the life of the project and are ready to reclaim within 10 years of the end-of-mine-life of that project.

Hogan said, ‘this is a shift towards the management of tailings in a way that respects the needs to mobilize new technologies and harness innovation so we can manage this size and scale of environmental impacts to a point we can move away and into reclamation.’ Directive 74 may have been abandoned, but the long-term goals that informed it are still in place.

So what does that mean for mining in Alberta? Are things getting easier or tighter? Overall, the new regulations are mining-friendly. They’re designed to facilitate industry expansion without making unacceptable environmental sacrifices. And that means they’re more long-term, but also that there’s a missing piece of the puzzle: for TMF to come together, new technology that isn’t online yet will be needed. Kyle Fawcett points out: ‘Technology unlocked the oilsands. It will be key to finding the long-term, effective solutions to tailings ponds management.’

Some of that new technology, though, is in place. PhotoSat has extensive experience working with players in the oil sands sector: while oil sands companies seek to accelerate tailings reclamation, reduce the need to build more tailings ponds and reduce their inventories of mature fine tailings, they struggle to do it without accurate, up-to-date survey data. Scanning tailings areas with GPS or ground-based LiDAR comes with a host of problems, including team safety.

50cm resolution satellite ortho photo

50cm satellite ortho photo

© DigitalGlobe 2014

 

1m PhotoSat elevation image (accurate to better than 15cm in elevation)

1m PhotoSat elevation image

1m contours (accurate to better than 15cm in elevation)

1m contours

 

By comparison, PhotoSat’s unique satellite surveying technology, facilitated by software that builds on seismic data processing tools, produces highly accurate elevation data faster, with better definition of steep slopes and without subjecting survey crews to risky environments. It’s a process that’s used to safely survey Suncor’s TRO (Tailings Reduction Operation) in Alberta. PhotoSat has mapped their tailings site twice monthly since 2013, as well as producing automated toes and crests. Many oil sands and other types of mines have adopted PhotoSat mapping to improve tailings monitoring and measurement.

To learn more about our topographic processing system, or to find out how it could facilitate your resource project, contact us at info@photosat.ca or 1-604-681-9770.

Texas elevation data

High Accuracy Elevation Grids (DEM) Available for Texas Oil Regions: Permian Basin, Eagle Ford Shale

PhotoSat has produced off-the-shelf digital elevation models for parts of the Permian Basin and Eagle Ford Shale in Texas. For oil producing areas in Texas that are outside of the immediately available data shown below, we can quickly produce a DEM using existing satellite imagery so contact us (info@photosat.ca) with your project area and we will provide details.

The vertical accuracy of the 1m elevation grids is better than 1m, making the data suitable for engineering and precision GIS tasks. The terrain data is bare earth (DTM) with man-made features and vegetation removed, making it ideal for development and construction planning. These DEMs are used by our oil and gas clients for:

  • Reducing costs by lowering the need for ground surveyors and eliminating multiple surveyors.
  • Well site and well pad design
  • Pipeline route, powerline, and road planning
  • Seismic planning
  • Slope analysis
  • Environmental assessment and planning

Our Texas digital elevation models are offered at an affordable price for such high accuracy and high resolution. Contact us with your project area in Texas and we will provide you with a quote.

Below are images of the current coverage available. If your project area is outside of this coverage, don’t fret, we can quickly produce detailed topography over most other areas.

Texas elevation data

Overview of off-the-shelf elevation data in Texas

 

Permian Basin DEM

Zoom of the DEM in the Permian Basin

 

Eagle Ford Shale DEM

Zoom of the DEM in the Eagle Ford Shale Play

 

The elevation mapping package includes:

  • 1m bare earth elevation grid (DTM) accurate to better than 1m
  • 50cm greyscale precision satellite ortho photo
  • 1m contours

 

Eagle Ford elevation mapping

1m colour image of the DTM over the Eagle Ford Shale

 

1m contours

1m colour image of the DTM with 1m contours

 

Satellite photo

50cm resolution satellite ortho photo

 

If you’d like a quote for topographic mapping over your project area contact us and we’d be happy to help. info@photosat.ca, 604-681-9770.

Mexico onshore oil and gas blocks

High Accuracy Surveying and Satellite Photos for Mexico Round 1 Onshore Blocks

As you probably already know, Mexico’s oil and gas blocks are up for auction and the next round includes the onshore fields. For bidding companies, detailed satellite elevation mapping and high resolution ortho photos can significantly help understand and assess the surface topography.

View the brochure for Mexico blocks satellite data (PDF).

Mexico onshore oil and gas blocks

Mexico onshore oil and gas blocks for bidding

 

PhotoSat can provide 30cm vertical accuracy, 1m bare earth elevation grids (DEM) for all blocks. These DEMs are produced from archive satellite images.

The benefits of having high accuracy surveying include:

  • Assessing environmental conditions including drainage and flood risk assessment.
  • Engineering grade accuracy allows for accurate assessments of the location of existing infrastructure (well sites, roads, pipelines etc).
  • Knowledge of the ground conditions reduces risk.

If the available satellite images used to produce the topographic data are too old for your purposes, we can acquire new satellite images on request. Contact us at info@photosat.ca for information on the data available over the block in question, and for pricing.

We can accommodate custom coordinate systems and are able to use many types of surveys for ground reference points. We can also produce the mapping without ground control points if nothing is available. More information on our 30cm accuracy satellite elevation mapping can be found on our main website.

If detailed base mapping is not required yet, we can also provide high resolution satellite ortho photos only over the desired block.

The following table outlines the existing 50cm resolution satellite images that are immediately available for all blocks. Included are the size of the block and the most recent ortho photo date. If you need more current information, we can task a satellite to collect new images.

Campos Burgos:
Block Size (sqkm) Archive ortho image date
Anahuac 30 October 2014
Duna 37 March 2014
Mareografo 30 March 2014
Calibrador 16 March 2014
San Bernardo 29 November 2013
Benavides 136 November 2013
Pena Blanca 26 June 2015
Carretas 90 November 2013
Ricos 24 August 2013
Campos Norte:
Block Size (sqkm) Archive ortho image date
La Laja 10 July 2014
Ponton 12 August 2015
Paso de Oro 23 October 2014
Tecolutla 7 January 2014
Barcodon 11 March 2015
Campos Sur:
Block Size (sqkm) Archive ortho image date
Moloacan 47 June 2015
Calicanto 11 May 2015
Cuichapa Pte 42 June 2015
Mayacaste 22 April 2015
Tajon 28 April 2015
Paraiso 17 April 2015
Fortuna Nacional 22 June 2015
Mundo Nuevo 28 May 2015
Topen 26 May 2015
Catedral 58 May 2015
Malva 22 May 2015
Secadero 10 May 2015

 

Our standard delivery is an ortho photo centered on each block covering 100 sq km. Pricing is based on the square kilometer, and custom sizes and shapes are available on request.

View the brochure for Mexico blocks satellite data (PDF).

Feel free to contact us for a quote, or for any questions: info@photosat.ca, 604-681-9770.

 

Accelerate Mining Volume Measurements with Satellite Topography

Accurate mine planning requires continually adjusting the plans for the situation on – and underneath – the ground. Resource quantities and locations are changing frequently, and mine layout is affected by blasting, tunneling and ore removal. That’s especially true in open pit mines, but all mining engineers face the difficulty of working with the same digital elevation data while the ground shifts.

In fact, that’s one problem that more efficient communication between the mine face and site and the engineer simply can’t solve, because no one on the ground has a high-level overview either. What’s needed is an update of the original elevation data to reflect what’s happened since.

A common method of doing this is with LiDAR (Light Detection and Ranging). But LiDAR is expensive and time consuming, so we need a mapping system that can be used more often. The only snag is that it has to both deliver similar accuracy and cost significantly less to permit more frequent use.

Step forward satellite topography.

Satellite topography using new, geophysical processing techniques results in similar accuracies to LiDAR and can be used for yearly, quarterly or monthly reconciliations, allowing engineers to work with accurate representations of what’s really happening on the ground. PhotoSat’s satellite elevation mapping for mining volumes has proven accuracies of better than 30cm, providing a clearer picture.

Mining volume changes over an open pit

Volume changes over an open pit mine

 

That means that when it’s time to make volumetric change measurements in pits, stockpiles, waste dumps and tailings, satellite mapping lets you view and analyze the situation simply and easily. Our clients tell us that one of the main advantages of using our satellite system is the ease with which they can check on as-built locations of buildings and structures and reconcile them to the original plan. Reconciliation can even be on a biweekly basis if the project is moving fast. That helps engineers with tailings management, and also makes life easier and safer for on-the-ground surveyors, resulting in greater accuracy and fewer injuries.

How can a satellite system deliver biweekly updates? Partly because after ground-based scans have been acquired, the images have to be compiled. In the case of a system like vehicle-mounted ILRIS (Intelligent Laser Ranging and Imaging) that’s the bottleneck; from raw data to point cloud to the computer processing and satellite location necessary to produce a useable image, nothing much can compete with the 8 days PhotoSat’s technology can take to produce a useable result.

Satellite image with mining volumes

Satellite photo with mining volume changes

 

Finally, using satellites rather than ground-based methods removes the need for surveying to take place on or near the mine site. As a result, the surveying process is safe and never needs to interfere with mine operations. There’s no risk of damage to vehicles or injury to surveying personnel when your imaging is done from space!

To find out more about how satellite topographic mapping can help make mining a safer and more efficient process, leave us a comment or contact us at info@photosat.ca.