Country-scale hyperspectral mineral maps, ready for GIS
Hyperspectral mineral maps used to be hard to build and difficult to use. Now they come as seamless, cloud-free, country-scale merges that open easily in your own GIS software. We have included three generously sized samples of our Equivest EMIT hyperspectral merge for download, ready to use out of the box. The article below takes you through the basics of hyperspectral mineral mapping and the method behind our product.
The ground against the Equivest merge
Left: the ground in a satellite image. Right: the Equivest merge of every EMIT frame over the same ground. Drag the handle to compare, and pick a deposit.
Easy to use in your GIS
Our products open out of the box in both QGIS and ArcGIS. Simply click the pixel to see the exact mineral.
Country-scale hyperspectral mineral mapping used to be a game only for the majors. The data came one frame at a time, a specialist would find the best cloud free frames, process each frame by hand, and the cost per frame was high enough that you would not order a survey unless you were in a prime location for remote sensing.
In 2026 that has changed. NASA's EMIT mission has imaged most of the bare land between 52° north and 52° south several times over. At Equivest we combine every one of those frames into a seamless merge, without clouds, with minimum vegetation and snow.
We deliver entire countries, even continents, in a single GeoTIFF that you can open in your preferred GIS software. A junior with a junior's exploration budget can now look at a whole shield the way only a major could, and get there first.
Later in this article you can read how DesertEx went from receiving the Equivest hyperspectral merge of the whole of Saudi Arabia to securing licences over previously unknown copper outcrops in just nine months.
The EMIT mission
The EMIT hyperspectral sensor has been riding on the International Space Station since 2022. Spatial resolution is 60 metres, across 285 spectral bands. NASA's own calibration paper describes the reflectance as "approaching the fidelity of manual field spectroscopy in some cases" 2. EMIT has been collecting a massive amount of overlapping images, so we have several, sometimes tens of frames covering the same area. The coverage is several times greater than that of the competing hyperspectral satellites EnMAP and PRISMA.
Below you can see the superior coverage of EMIT compared to EnMAP and PRISMA. However, EnMAP and PRISMA do have better spatial resolution at 30-metre pixels, while EMIT has 60 metres.
EnMAP and PRISMA have 30 m pixels, and their frames can sharpen a target once it is found. Large deposits usually come with large footprints. While we are looking to add EnMAP capability, we believe 60 m pixels are sufficient to find large deposits.
For the mineral classification, NASA's Jet Propulsion Laboratory, with the Planetary Science Institute and the USGS, uses the Tetracorder expert system developed by Roger Clark 1. Tetracorder brings some unique advantages. Firstly, it has been tried and tested for decades on Earth, the Moon and Mars, and it already guides test rovers that explore on their own 4. The USGS has spent decades checking its maps against field samples at desert sites such as Cuprite, Nevada 3, 5.
Secondly, Tetracorder is an expert system based on the science of material spectroscopy. Each mineral is characterised by its unique absorption features, which exist only in one or a few small portions of the spectrum. Instead of trying to match the entire reference library to the whole reflectance curve, it focuses on the parts where those absorption features are located. Other methods that use the entire reflectance curve do not know where the specific absorption features sit, and the reference spectrum that best fits the whole curve is likely to overlook the small but very important features that Tetracorder focuses on.
Equivest hyperspectral mineral maps are built on a pipeline that evaluates every pixel, to make sure we get the most reliable mineral prediction across all frames taken. We select the cloud-free, snow-free and minimum-vegetation pixels across all scenes. For every pixel, we then merge the mineral predictions from all the remaining frames into one map, keeping the mineral that most frames agree on. Over Filo del Sol, two EMIT frames over the same pixel name a different mineral family 38% of the time, and a single frame disagrees with our merge on 26% of its pixels. With multiple frames covering the same pixel, we are able to remove that noise.
Single EMIT frame versus the Equivest merge
To the left you can see the mineral map built on a single EMIT frame. To the right you can see a much more consistent and de-noised image built on the best pixel acquired over time.
How much do the frames disagree?Two numbers from every EMIT frame over Filo del Sol
This results in a very low-noise, consistent, seamless country or continental scale merge that opens out of the box in QGIS or ArcGIS. We have added our own colour bar grouping the classes into families: advanced argillic, white micas and illite, the kaolin group, smectites, chlorite, epidote and carbonates. Click on a pixel and you see the exact USGS reference record.
Colour bar grouped by mineral family
Each row is a family in the main colour the map gives it. Open a family to see every reference record underneath; hover one for its USGS library name.
The minerals come in two groups. Group 1 comprises the iron-bearing minerals, identified from their absorption features near 1 µm. Group 2 comprises the clays, micas, carbonates and sulphates, identified from absorption features near 2 µm 1.
Diagnostic absorption regions of the two mineral groups
USGS laboratory spectra resampled to EMIT's bands and offset for clarity. Group 1 minerals are identified from broad iron absorptions below about 1.3 µm; group 2 minerals from narrow absorptions between about 2.1 and 2.4 µm.
Find what was missed before the window closes
At Equivest, we believe the combination of cloud computing and hyperspectral satellite imagery will lead to the last outcropping, untested lithocaps being identified and drilled over the next couple of years.
As the availability of hyperspectral imagery goes up, and the cost of turning it into seamless country-scale mineral maps goes down, the opportunity will not last for decades.
Today, both majors and juniors can access this data at scale, and the last giants that reveal their presence to space will soon be found.
DesertEx is a company that took the first-mover advantage into their own hands when Saudi Arabia opened its first rounds of exploration licensing. DesertEx went from the EMIT mineral map to securing exploration rights over outcropping copper at surface in just nine months. DesertEx was part of the BHP Xplor 2025 cohort, BHP's accelerator for early-stage explorers, and DesertEx CEO Oliver Jones tells the story at the BHP Xplor Showcase.
Credits
These products stand on the shoulders of others. NASA's Jet Propulsion Laboratory built and operates EMIT and makes every frame freely available. The mineral predictions are based on the work of Roger Clark and his colleagues at the USGS and the Planetary Science Institute, who developed the Tetracorder algorithm and the USGS spectral library it draws on 3, 4, and on the work of the JPL, USGS and PSI team that runs it on every EMIT frame 1. The reference library and the identification engine identify the clays, micas, sulphates and carbonates of hydrothermal alteration well, and that is what makes it an excellent base for mineral exploration. Our clients have confirmed it on the ground.
Samples to download
If you want to try the product, download the samples for Escondida (Chile), Filo del Sol (Argentina-Chile border) and Cuprite (Nevada). Each package holds the Equivest merge for group 1 and group 2 as GeoTIFFs with the mineral names and colours built in, a raster with the number of frames merged at each pixel, a ready-made QGIS project and ArcGIS layer file, and single NASA frames over the same ground for comparison.
In the next article we will publish a more detailed data package, with the abundance of each mineral, plus custom layers based on the research of CSIRO.
Contact us
Contact us if you are interested in regional, country-scale or continent-scale data. Please contact us for more information and pricing at info@equivestmetals.com, or by phone or WhatsApp on +47 412 22 466.
References
- Brodrick, P.G., Clark, R.N., Swayze, G.A., et al., 2023. EMIT L2b Algorithm: Mineral Detection and Related Products at the Pixel Scale. Algorithm Theoretical Basis Document, JPL D-104479. lpdaac.usgs.gov
- Thompson, D.R., Green, R.O., Bradley, C., Brodrick, P.G., Mahowald, N., Ben-Dor, E., et al., 2024. On-orbit calibration and performance of the EMIT imaging spectrometer. Remote Sensing of Environment 303, 113986. doi:10.1016/j.rse.2023.113986
- Clark, R.N., Swayze, G.A., Livo, K.E., Kokaly, R.F., Sutley, S.J., Dalton, J.B., McDougal, R.R., Gent, C.A., 2003. Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems. Journal of Geophysical Research 108(E12), 5131. doi:10.1029/2002JE001847
- Clark, R.N., Swayze, G.A., Livo, K.E., Brodrick, P., et al., 2024. Imaging Spectroscopy: Earth and Planetary Remote Sensing with the PSI Tetracorder and Expert Systems from Rovers to EMIT and Beyond. The Planetary Science Journal 5(12), 276. doi:10.3847/PSJ/ad6c3a
- Swayze, G.A., Clark, R.N., Goetz, A.F.H., et al., 2014. Mapping advanced argillic alteration at Cuprite, Nevada, using imaging spectroscopy. Economic Geology 109(5), 1179–1221. doi:10.2113/econgeo.109.5.1179
Further watching
- Roger Clark's Spectroscopy and Tetracorder Training playlist (PSI): youtube.com
- The open-source Tetracorder code: github.com/PSI-edu/spectroscopy-tetracorder
- NASA's EMIT mission page: earth.jpl.nasa.gov/emit
Equivest Metals Oy sells these products as a reseller for Vest Capital SL, which owns the products and the methods behind them.