iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
Short answer: Compare a satellite system on three separate axes: the resolution of the specific sensor band you need, the swath width that determines how much ground one pass can cover, and the revisit interval—stating whether that interval belongs to one spacecraft or a constellation. Sentinel-2 and Landsat 8/9 illustrate why no single figure identifies the best satellite for every job.
Start by separating the three questions
Satellite specifications often place a resolution number, a swath number, and a revisit number side by side. They describe different operational questions:
- Resolution: What is the nominal ground sampling scale, and which instrument and spectral band provide it?
- Coverage: How wide a strip does the sensor image across the flight path during one pass?
- Revisit: How long until the same location can be observed again, and is the figure for one satellite or several spacecraft working together?
A system can have fine pixels but a narrower swath, or a wide swath but coarser pixels. A short nominal revisit still may not produce a usable optical image when clouds obscure the target. Compare the three measures independently before combining them for a mission decision.
Recommended Free Tools
Resolution: tie every number to a band and sensor
Spatial resolution is normally expressed as the nominal ground dimension represented by a pixel or sampling element. A smaller metre value indicates finer nominal spatial sampling, but it does not by itself prove that a particular feature will be distinguishable. Spectral range, contrast, image quality, processing, viewing geometry, and the feature itself also matter.
#1 Best Overall
Sentinel-2 MSI band groups
The Sentinel-2 MultiSpectral Instrument (MSI) has 13 bands spread across three spatial resolutions. The frequently advertised 10 m figure applies to only four bands.
| Sentinel-2 MSI bands | Nominal spatial resolution | How to use the figure |
|---|---|---|
| Four bands | 10 m | Use when the required analysis uses one of these four bands. |
| Six bands | 20 m | Do not substitute the 10 m headline for these bands. |
| Three bands | 60 m | These bands have a substantially coarser sampling scale. |
Sentinel-2 documentation also lists a 290 km swath and a 5-day revisit for the combined mission. Those figures describe the mission as a system; the single-spacecraft cycle is 10 days in the technical documentation.
Landsat 8 OLI/TIRS resolutions
Landsat 8 combines the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). Its published examples separate multispectral, panchromatic, and thermal products:
| Landsat 8 product or sensor type | Nominal spatial resolution | What the distinction means |
|---|---|---|
| Multispectral imagery | 30 m | Use for the listed visible, near-infrared, and shortwave-infrared multispectral data. |
| Panchromatic band | 15 m | Finer sampling in a single broad band, not the same as 15 m multispectral colour imagery. |
| Thermal imagery | 100 m | Use when the requirement is thermal measurement rather than reflected-light detail. |
NASA and the U.S. Geological Survey list a 185 km swath and a 16-day repeat for an individual Landsat 8 spacecraft. Landsat 8 and Landsat 9 are offset to observe a location at an 8-day interval.
Why the headline resolution can mislead
- It may describe only one band. Sentinel-2’s 10 m value does not apply to its 20 m and 60 m bands.
- Panchromatic and multispectral values are different products. A 15 m panchromatic image is not equivalent to 15 m colour or infrared imagery.
- Pixel size is not a universal quality score. A coarser band can be the right choice when its spectral or thermal information answers the question.
- Nominal sampling is not guaranteed object recognition. A target’s size, contrast, orientation, atmospheric conditions, and processing affect whether it can be identified.
Coverage: understand swath width
Swath width is the cross-track width of the ground strip imaged during a pass. Holding other factors equal, a wider swath can cover a larger strip in one overpass. It is not the total area a mission covers over a week, and it is not a promise that every metre of that strip will yield a usable, cloud-free product.
Rank #2
| System | Nominal swath | Interpretation |
|---|---|---|
| Sentinel-2 MSI | 290 km | Wider nominal ground strip per pass in this comparison. |
| Landsat 8 OLI/TIRS | 185 km | Narrower strip per satellite pass. |
Swath is not the same as usable coverage
Orbit tracks, acquisition plans, viewing geometry, terrain, and clouds determine how much of the nominal strip becomes useful imagery. The USGS notes that overlap between adjacent Landsat swaths varies strongly with latitude: about 7% at the equator and approximately 85% at extreme latitudes. Consequently, the same nominal swath cannot be converted into one fixed area-per-day figure for every location.
For a large-area mapping project, use swath as one planning input. You also need the satellite’s orbit pattern, the number of passes that intersect the area, scene boundaries, processing level, and an estimate of how often clouds will block optical observations. None of those practical factors is captured by the swath number alone.
Revisit time: distinguish a spacecraft from a constellation
A revisit or repeat figure states how frequently a location can be observed under the mission’s nominal orbital capability. Always label the scope of the number.
| System | Single-spacecraft repeat | Combined mission interval | Source qualification |
|---|---|---|---|
| Sentinel-2 | 10 days | 5 days | The 10-day value is for one satellite; the 5-day value is for the combined Sentinel-2 constellation. |
| Landsat 8 | 16 days | 8 days with Landsat 9 | The 16-day value is the individual repeat; the paired Landsat 8/9 mission provides an 8-day observation interval at a location. |
Calling Sentinel-2 a five-day satellite or Landsat 8 an eight-day satellite without qualification hides the difference between one spacecraft and a coordinated pair. For scheduling, the constellation interval is usually the relevant capability, while the individual repeat matters for spacecraft-specific analysis and continuity planning.
Nominal revisit is not cloud-free cadence
Sentinel-2 and Landsat optical instruments can be scheduled to pass over a location while clouds prevent a useful surface observation. The specifications cited here do not provide a universal cloud-free probability. Treat revisit as an opportunity to acquire data, not a guarantee of a clear image. Your actual usable cadence depends on local weather, season, cloud screening, snow or haze requirements, and the quality threshold for the project.
Side-by-side comparison
| System | Resolution examples | Swath | Repeat or revisit | Best comparison question |
|---|---|---|---|---|
| Sentinel-2 MSI | Four bands at 10 m; six at 20 m; three at 60 m | 290 km | 10 days for one satellite; 5 days for the combined constellation | Do the bands needed for the analysis have the required sampling, and is the constellation cadence sufficient? |
| Landsat 8 OLI/TIRS | 30 m multispectral; 15 m panchromatic; 100 m thermal | 185 km | 16 days for one satellite | Is the multispectral, panchromatic, or thermal product the deciding requirement? |
| Landsat 8/9 constellation | Landsat-family instruments retain the listed characteristics | 185 km per satellite | 8 days at a location | Is a consistent, long-running land-imaging record more important than the finest nominal pixel size? |
This table does not rank the missions universally. It shows why the answer changes with the feature, area, spectral information, cadence, and historical record you need.
Free tools Windows power users keep installed
One-click scans. No signup required.
A practical comparison workflow
Use the following sequence when choosing between documented satellite options or evaluating a new mission specification.
- Define the smallest feature that matters. Write down whether you need to map broad land-cover patterns, distinguish field-scale variation, detect a narrow linear feature, or measure temperature. Then identify the band or product that actually contains the required signal.
- Record resolution by band or sensor. Do not enter a single headline number in your comparison sheet. For Sentinel-2, record the 10 m, 20 m, and 60 m groups separately. For Landsat 8, record multispectral, panchromatic, and thermal values separately.
- Estimate the area and geometry. Compare the 290 km Sentinel-2 swath with the 185 km Landsat swath, then check how the orbit crosses your area. A wide swath can reduce the number of strips needed, but latitude-dependent overlap and scene layout still affect coverage.
- Choose the correct revisit scope. Mark each figure as single spacecraft, paired mission, or larger constellation. Use 10 days for one Sentinel-2 satellite and 5 days for the combined mission; use 16 days for one Landsat 8 satellite and 8 days for the Landsat 8/9 pair.
- Translate nominal cadence into usable cadence. Add cloud, haze, snow, seasonal, and quality-screening constraints. If your decision depends on a cloud-free interval, do not present the nominal repeat as the answer.
- Check spectral and thermal requirements. A 15 m panchromatic product may not replace a 30 m multispectral product, and a fine optical band cannot replace Landsat’s documented 100 m thermal product when temperature is the required measurement.
- Consider continuity. If you are extending a historical land record, consistent instrument characteristics and processing may matter more than selecting the smallest metre value in isolation. Landsat 8/9’s paired 8-day interval is useful in that continuity-oriented context.
- Document assumptions. In the final comparison, write the location, date range, bands, constellation scope, cloud policy, and minimum acceptable product quality beside every number.
How the framework changes by use case
Frequent vegetation or land-change screening
Start with the Sentinel-2 bands that meet your spectral requirement, rather than assuming all 13 bands are 10 m. The combined mission’s nominal five-day revisit and 290 km swath can provide frequent opportunities over broad areas. Whether that becomes a useful time series still depends on cloud screening and the local acquisition geometry.
Long-term, consistent land monitoring
Landsat 8/9 offers a documented eight-day location interval when the two spacecraft are considered together, while each Landsat 8 spacecraft has a 16-day repeat. Its 30 m multispectral, 15 m panchromatic, and 100 m thermal products let you choose the measurement type explicitly. This makes the instrument family a logical candidate when continuity and clearly separated optical, panchromatic, and thermal products are central requirements.
Thermal analysis
Put the thermal requirement first. Landsat 8’s listed thermal resolution is 100 m, which is a different product class from its 30 m multispectral and 15 m panchromatic imagery. Comparing only the smallest optical number would answer the wrong question.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Large-area acquisition planning
Use swath width to estimate how many ground strips may be needed, then account for orbit geometry and latitude. Sentinel-2’s 290 km nominal swath is wider than Landsat 8’s 185 km swath in these specifications. That advantage is about the width of each imaged strip, not a guarantee of cloud-free area or a fixed weekly coverage total.
Reading specifications without overinterpreting them
Keep three labels beside every number in a spreadsheet: the measurement type, its scope, and its qualification. For example, “10 m, Sentinel-2 MSI, selected bands” is more useful than “Sentinel-2 resolution: 10 m.” Likewise, “5 days, combined Sentinel-2 mission, nominal revisit” communicates more than “revisit: 5 days.” This habit prevents a band-specific value from being applied to an entire instrument and prevents a constellation capability from being attributed to one spacecraft.
Also separate a sensor specification from a delivered product. A specification describes nominal sampling or orbital capability. A product may be resampled, mosaicked, cloud screened, or otherwise processed, so its pixel grid should not be treated as proof of the original instrument’s detail. When comparing products, record the native band resolution and the processing step that produced the file you will analyze.
Planning a defensible acquisition schedule
- Set the observation window. State the start and end dates and whether the project needs one clear scene or a repeat time series.
- Define acceptable conditions. Specify cloud, haze, snow, or other exclusions before counting images. A nominal pass that fails those tests is not a successful observation for the project.
- Map the target against paths and swaths. Check which orbit tracks intersect the area and whether adjacent scenes overlap. Landsat overlap is especially latitude-dependent, ranging from about 7% near the equator to approximately 85% at extreme latitudes.
- Count opportunities by scope. Use the one-satellite cycle when only one spacecraft or instrument is allowed; use the combined interval when the project can use both members of a constellation.
- Report uncertainty honestly. Present revisit as an acquisition opportunity and provide a separate expectation for usable observations based on local conditions, rather than converting the interval into a guaranteed delivery date.
Common comparison mistakes and corrections
- Mistake: calling 10 m the resolution of every Sentinel-2 band.
Correction: list the four 10 m, six 20 m, and three 60 m bands separately. - Mistake: treating a panchromatic value as multispectral resolution.
Correction: keep Landsat 8’s 15 m panchromatic and 30 m multispectral products in separate columns. - Mistake: using swath as an area-total or cloud guarantee.
Correction: describe it as the cross-track width of the imaged strip and model orbit geometry and weather separately. - Mistake: quoting a constellation interval as a single-satellite repeat.
Correction: label Sentinel-2’s 5-day figure as combined-mission revisit and its 10-day figure as one-satellite cycle; label Landsat 8/9’s 8-day interval separately from Landsat 8’s 16-day repeat. - Mistake: assuming a scheduled pass equals a usable observation.
Correction: apply cloud and quality screening to the acquisition schedule. - Mistake: ignoring latitude.
Correction: account for the USGS-documented change in Landsat swath overlap, from about 7% at the equator to approximately 85% at extreme latitudes. - Mistake: declaring a universal winner from one metric.
Correction: score each candidate against feature size, area, cadence, spectral or thermal needs, and record continuity.
Specification checklist
Before approving a satellite comparison, verify that the document answers all of these questions:
- Which instrument and band produce the quoted resolution?
- Are multispectral, panchromatic, and thermal products separated?
- Is swath identified as a nominal cross-track width rather than total usable area?
- Does the revisit figure apply to one spacecraft or a constellation?
- Are latitude, orbit geometry, and scene overlap considered for the target area?
- Does the schedule distinguish nominal opportunities from cloud-free usable observations?
- Do the selected bands provide the spectral or thermal information the task requires?
- Is continuity of the imaging record part of the decision?
When those questions are explicit, the comparison becomes a traceable decision rather than a contest between isolated headline numbers.
Best Value
- Used Book in Good Condition
Frequently Asked Questions
Which satellite has the highest resolution in this comparison?
There is no single winner across all products. Sentinel-2 has four 10 m bands, while Landsat 8 has a 15 m panchromatic band, 30 m multispectral imagery, and 100 m thermal imagery. The relevant choice depends on the band and measurement you need.
What is satellite swath width?
Swath width is the cross-track width of the ground strip imaged during one pass. Sentinel-2 is listed at 290 km and Landsat 8 at 185 km. Swath is not a guaranteed cloud-free area total.
How often does Sentinel-2 revisit a location?
The technical documentation gives 10 days for one satellite and 5 days for the combined Sentinel-2 constellation. Those are nominal acquisition opportunities, not guaranteed clear images.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Clear out junk files and repair common Windows errorsFree Scan →How often does Landsat revisit a location?
An individual Landsat 8 spacecraft has a 16-day repeat. Landsat 8 and Landsat 9 are offset to provide an 8-day observation interval at a location.
Is a 15 m panchromatic image the same as 15 m colour imagery?
No. Landsat 8’s 15 m figure applies to a panchromatic, single broad-band product. Its listed multispectral imagery is 30 m, so the two products should be compared separately.
Does a five-day revisit mean I will receive a clear image every five days?
No. Clouds, haze, snow, seasonal conditions, acquisition plans, and quality screening can make a scheduled pass unusable. Revisit describes opportunity, not cloud-free cadence.
Which specification matters most for thermal mapping?
Use the thermal product’s specification first. Landsat 8 lists 100 m thermal resolution, which is distinct from its 30 m multispectral and 15 m panchromatic products.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
The Bottom Line
Bottom line: Compare the required band-level resolution, nominal swath, and correctly scoped repeat interval, then adjust the result for latitude, orbit geometry, clouds, and continuity needs. Sentinel-2 offers 10 m, 20 m, and 60 m bands, a 290 km swath, and a five-day combined-mission revisit; Landsat 8 offers 30 m multispectral, 15 m panchromatic, and 100 m thermal products, a 185 km swath, and a 16-day single-spacecraft repeat, or eight days with Landsat 9. The best system is the one whose specific measurements and usable cadence match the job.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
