Hyperspectral Mineral Mapping: 4 Satellites Compared

What hyperspectral mineral mapping can show from orbit

Hyperspectral mineral mapping uses a satellite sensor that records hundreds of narrow colour bands (232 to 285 on EnMAP, PRISMA and EMIT) between visible light and the shortwave infrared, so each 30 to 60 m pixel carries a full spectrum that can be matched to clays, micas, carbonates and iron oxides. EnMAP, for example, records 232 bands from 420 to 2450 nm at 30 m (DLR), and NASA’s EMIT records 285 bands from 381 to 2493 nm at 60 m (NASA Earthdata).

The maps show surface minerals, not ore. A hyperspectral scene will not show a gold nugget or a copper orebody under cover. What it shows is the rock and soil on top: the alteration clays, iron stains and carbonates that often surround a mineral system. That makes it a screening tool for licence owners deciding where to send a geologist, for consultants building a target list, and for investors checking whether a project’s story matches the ground.

This guide covers the sensors that exist today, what each can and cannot map, the steps from raw scene to mineral map, how to buy hyperspectral satellite imagery, and a calculator that shows how many pixels your licence will get.

How minerals show up in a hyperspectral spectrum

Every pixel in a hyperspectral image is a short spectrum: the share of sunlight the ground reflects at each wavelength. Minerals absorb light at set wavelengths, and those dips act as fingerprints. The strongest ones for exploration sit in two zones.

• Visible and near infrared (about 400 to 1,000 nm). Iron oxide minerals such as hematite and goethite, the rusty stains over many sulphide systems, leave their marks here. Hyperion, an older NASA sensor, was used to map iron oxide minerals from this range (Pour and Hashim, Springerplus).
• Shortwave infrared (about 1,000 to 2,500 nm). Hydroxyl-bearing minerals, sulphates and carbonates absorb between 2,000 and 2,500 nm, which is why Hyperion’s shortwave bands could map them in hydrothermal alteration zones (same review). A feature near 2,200 nm, called an Al-OH feature (aluminium bound to a hydroxyl group), is the classic sign of white mica such as muscovite or illite, and of kaolinite (USGS, R. Kokaly workshop slides).

The reason hyperspectral beats broad-band imaging is the width of each band. A feature that is a few tens of nanometres wide disappears when a sensor averages 100 nm of the spectrum into one number. With a band every 5 to 12 nm, the dip stays visible, and its exact position helps tell similar minerals apart, such as kaolinite from white mica.

▶ Spectral signatures explained: why shortwave infrared does the work in mining. · 1:49

Hyperspectral satellites used for mineral exploration

This guide covers four hyperspectral satellites that civil users can access as of November 2026, plus an older one, Hyperion, which left an archive. Other missions exist or are planned. The table lists what each offers a mineral explorer. Values come from the operators’ own pages and papers.

Chart

Wavelength range of four hyperspectral satellites

nanometres, visible to shortwave infrared

Sources for each row: EnMAP mission page, eoPortal on PRISMA, NASA Earthdata on EMIT, the Tanager-1 paper in Atmospheric Measurement Techniques and Planet’s hyperspectral page.

Two points matter for mineral work. First, all four reach 2,450 to 2,505 nm, so they all cover the shortwave region where alteration clays are read. Second, the pixel is 30 m on three of them and 60 m on EMIT. A 60 m pixel averages 3,600 square metres of ground, so a narrow vein or a small alteration halo mixes with its surroundings.

The chart below compares the wavelength range each satellite covers.

Hyperspectral vs multispectral: what changes for a geologist

Multispectral satellites record a handful of wide bands. Sentinel-2 has 13 spectral bands and a 290 km swath, with a revisit of about five days at the equator when both satellites fly (ESA). It is well suited to regional iron-oxide and clay ratios and to change over time, and it is the base for most satellite exploration screens.

Chart

Spectral bands per sensor

number of bands (ASTER’s six shortwave bands have been unusable since 2008)

ASTER, a US-Japan instrument, has six shortwave infrared bands at 30 m that were widely used for alteration mapping. NASA’s data page states that its shortwave data have not been included in the standard product since 1 April 2008 because of detector anomalies, with saturation and striping (NASA Earthdata, ASTER L1T). Older ASTER archives are still used in studies, which is one reason hyperspectral missions matter: they bring back shortwave coverage at a finer spectral scale.

In practice the difference is this. A multispectral map can tell you that a hillside carries clay or iron staining. A hyperspectral map can often tell you which clay it is, and that changes the interpretation. In a hydrothermal system, different clay minerals mark different alteration zones, so the choice between kaolinite and white mica can shift where you would sample. The two approaches work together: Sentinel-2 for the wide screen and frequent revisits, hyperspectral for the scenes that matter.

The chart compares the number of spectral bands per sensor.

Minerals a hyperspectral satellite can and cannot map

Hyperspectral sensors map minerals that absorb light in the visible to shortwave range and that outcrop at the surface. A satellite does not see gold, diamonds or cobalt metal. For most ore metals, what it sees is the host rock and the alteration around the deposit. A few minerals that carry lithium, such as spodumene or hectorite clay, can have shortwave features of their own, so a lithium target may be mapped more directly than a gold one, but it still needs sampling to confirm.

What it cannot do is as important. It does not see through soil, cover or dense forest. It does not give grade, and it does not replace sampling. Treat every output as an exploration target that sits ahead of a drilling programme and well before a resource estimate.

The right way to use a mineral map is as a filter. If a claim you are looking at sits where alteration clays and iron oxides line up with known mineralisation nearby, the screen is encouraging. If the map shows only bare, unaltered rock, that is a reason to ask harder questions. Neither outcome is proof.

From raw scene to mineral map in five steps

A hyperspectral scene is a cube of hundreds of images stacked together. Turning it into a map follows a fixed sequence, and skipping a step is the usual cause of misleading maps.

Infographic

Raw scene to mineral map

1. 1CorrectConvert radiance to surface reflectance.
2. 2MaskRemove cloud, water, snow and vegetation.
3. 3MatchCompare each spectrum with reference minerals.
4. 4MapGroup matches into alteration zones.
5. 5VerifySample the mapped zones on the ground.

1. Convert to surface reflectance. Raw radiance includes the atmosphere. Correction removes water vapour and aerosol effects. NASA offers EMIT in both radiance and estimated surface reflectance for this reason.
2. Mask what is not rock. Cloud, shadow, water, snow and green vegetation are removed or flagged, because they hide or mimic mineral features.
3. Match each pixel to reference spectra. Algorithms compare each spectrum with library spectra and report the best match, the depth of the absorption and the uncertainty. NASA’s EMIT level 2B product reports estimated mineral identification, band depth and uncertainty (NASA Earthdata).
4. Group into mineral and alteration maps. Matches are combined into units such as white mica zones or iron oxide zones, and checked against geology and structure.
5. Check on the ground. A geologist samples a few of the mapped zones and uses a hand spectrometer or lab data to confirm the match.

USGS scientists have compared mineral maps from NASA’s airborne AVIRIS instrument with maps from the orbital EMIT and EnMAP sensors, and note that more comparisons are needed and that reflectance updates for both satellites were underway (USGS workshop slides). Ask any supplier which processing version of the data it used. Note that a mineral map carries no tonnes or grade: turning a target into a tonnage figure needs drilling and sampling data.

▶ How a satellite picture becomes a tonnage and grade estimate, and what is measured or assumed. · 2:54

How to buy hyperspectral satellite imagery

You buy or request hyperspectral imagery in one of three ways, and the route depends on the sensor.

Chart

Swath width of one pass

kilometres

• Commercial tasking. Planet describes tasking, ordering and delivery of Tanager data through its APIs, and invites buyers to get in touch; its page stresses methane detection, so ask whether mineral-mapping collections are offered (Planet). This is the route when you need a new image of a specific licence on a specific schedule.
• Agency archives. NASA’s LP DAAC distributes EMIT data at level 1 and higher, and ASI lets registered users search PRISMA’s catalogue and request acquisitions through its web portal (eoPortal). These archives suit research and screening, though coverage of your exact area is not guaranteed.
• A processed result. Many buyers do not want a data cube. They want a map and a short report. A service provider takes your boundary, selects scenes, processes them and delivers the interpreted layers.

Before you pay for anything, ask five questions. Does a scene already exist over the area? What are the acquisition date and the cloud and vegetation cover? Is it radiance or reflectance, and which version? Which pixel size will you get? And will the vendor deliver mineral maps or only the raw cube? Prices vary by vendor and by area, so ask for a written quote for your own boundary.

The chart compares the swath width, the strip of ground one pass covers, for the same sensors.

How many pixels will your licence get?

Pixel size decides whether a target is mapped or lost in the average. The calculator below converts a licence area and a pixel size into a pixel count, and tells you how many pixels would span a feature of your chosen width.

Limits to check before you rely on a map

Hyperspectral mapping has real limits, and a good report states them.

• Surface only. The sensor reads the top of the ground. Transported cover, weathering crusts and soil can hide the rock below.
• Vegetation. Dense green cover blocks the signal. Arid and semi-arid ground works best, and the review by Pour and Hashim also points to arid and semi-arid regions.
• Mixed pixels. At 30 to 60 m, one pixel often holds several materials. Narrow features can blur.
• Revisit and cloud. EnMAP’s nadir revisit is 27 days and Tanager’s swath is only about 19 to 20 km, so a scene over your licence may not exist for the season you need.
• Processing differences. Different algorithms and library spectra can give different mineral names for the same pixel. Ask for the validation evidence.
• Not a resource. Nothing here gives tonnes or grade. Results are exploration targets and do not meet JORC or NI 43-101 standards on their own.

There is also a field rule: checking a mapped zone on foot needs the landholder’s permission, a valid licence and safe practice, and no mercury should ever be used in any sampling or panning.

▶ The three limits of satellite exploration that matter in due diligence. · 2:08

Where hyperspectral maps fit in an exploration programme

For a licence owner, hyperspectral mapping is an early look at where alteration sits inside the boundary, before soil lines or drilling. For a consultant, it is a way to rank blocks and to design a sampling plan that targets the mapped zones instead of a regular grid. For an investor, it is a reality check: if a promoter claims a large alteration system, public satellite archives can show whether the claimed minerals appear at the surface.

Farmonaut works from satellite data inside a boundary you supply, using KML, KMZ or polygon files, and delivers mineral and alteration maps as exploration targets. If you want a satellite screen of your own ground, you can request a quote, read the overview of satellite-based mineral detection, or contact the team. For wider context, see our guides to remote sensing in mineral exploration, copper deposits and porphyry copper.

Frequently asked questions

What is hyperspectral imaging in mining?

It is imaging with hundreds of narrow bands, so each pixel holds a spectrum. In mining it is used to map surface minerals and alteration, from the air or from orbit, as a guide for where to sample.

What is hyperspectral mineral mapping?

It is the process of matching each pixel’s spectrum to reference mineral spectra to produce a map of clays, micas, carbonates and iron oxides. EMIT’s level 2B product is an example: it reports mineral identification, band depth and uncertainty.

Which satellites offer hyperspectral imagery for mineral exploration?

EnMAP, PRISMA, EMIT and Tanager-1 all cover the visible to shortwave range. See the comparison table above for bands, pixel size and access route.

How do I buy hyperspectral satellite imagery?

For Tanager, contact Planet for tasking through its APIs. For EMIT and PRISMA, use the agency portals. For a finished interpretation, ask a service provider for a quote over your boundary.

What is the difference between hyperspectral and multispectral?

Multispectral sensors such as Sentinel-2 record 13 wide bands. Hyperspectral sensors record hundreds of narrow ones (232 to 285 on EnMAP, PRISMA and EMIT), which lets them separate minerals that look alike in wide bands.

Can hyperspectral satellites find gold?

Not directly. They map the alteration minerals and iron oxides that often accompany gold systems. A positive map is a reason to sample, not proof of gold.

What is hyperspectral remote sensing for mineral exploration used for?

Common uses are screening a region, ranking blocks of a licence, designing sampling and checking third-party claims. It comes before ground work and drilling.

How accurate is hyperspectral imaging for mineral exploration?

It depends on cover, pixel size and processing. USGS scientists comparing orbital and airborne maps say more comparisons are needed, so ask for ground validation.

What does hyperspectral imaging do in geology beyond ore search?

It also maps rock units, carbonate and clay distribution and weathering, which helps geological mapping where outcrop is poor.

Does hyperspectral imaging work under vegetation?

Poorly. Dense green cover hides the ground, so results are best in arid and semi-arid terrain or on bare rock.