Levels of Accuracy

PhotoSat provides a range of survey products for variety of clients. The level of accuracy is influenced by the number of ground control points (GCP) and the satellites used to capture images.

If you have existing survey data, we can combine it with our survey data.

Surveying for operating mines and earthworks

For applications in operating mines or earthworks construction, PhotoSat produces elevation surveys with high accuracy: around 15 cm RMSE or better.

To achieve this, we use specific satellites and apply as many GCPs as possible. The accuracy of our elevation surveys typically increases with more ground control points (GCP). See below.

For areas of 100 km2:

Level of Accuracy GCPs (per 100 km2) Over Horizontal Distance Satellites Applications
<15 cm (absolute) <150 10 km WorldView-1



Operating mines:

  • Tailings volumes
  • Mined ore volumes
  • Tailings beach lifts
  • Dam breach studies

Earthworks construction:

  • Structure movement tracking
  • Cut and fill volumes
  • Detailed construction design
15 cm – 20 cm (absolute) <75 10 km WorldView-1



Wind turbine construction

Mine development

Surveying for planning and exploration

For applications such as mining exploration or preliminary planning, high accuracy surveying is not always necessary.  When suitable for your application, we can use a broader selection of satellites or apply fewer GCPs.

Even with no GCPs, PhotoSat surveys are still quite accurate at 20 cm relative accuracy. See below.

For areas of 100 km2:

Level of Accuracy GCPs (per 100 km2) Over Horizontal Distance Satellites Applications
20 cm – 30 cm (absolute) <20 10 km WorldView-1



Mine development

Mine exploration

30 cm – 50 cm (absolute) <10 10 km Kompsat-3A Preliminary exploration
1 m – 2 m (absolute) <5 10 km ALOS PRISM


Preliminary exploration

Terrain assessment

20 cm (relative) None 5 km WorldView-1



Preliminary planning

Preliminary exploration

Surveying without Ground Control Points (GCPs)

In some cases, it may be necessary to complete elevation surveys before ground control points are established. This is often the case in regions where security is not guaranteed, or in extremely remote areas. These elevation surveys are still relatively accurate, at about 20 cm elevation accuracy.

GCPs can be applied later 

If ground survey data becomes available after a PhotoSat survey has been delivered, we can reprocess the satellite photos and adjust the PhotoSat survey to match the new ground survey data.  The cost to reprocess and reissue the PhotoSat survey depends on the size of the survey area.

For example, survey target areas of 100 km2 can be reprocessed for approximately $2,500 USD.