While both can provide high-resolution data, they serve different project needs. The right approach depends on factors such as acquisition date and cloud cover.

Archive Satellite Imagery Explained

Satellite imagery that has already been captured by providers is called archive imagery. You can search for available imagery on LandEye using filters like:

• AOI
• Acquisition date
• Sensor
• Resolution
• Cloud cover

The primary benefit of this imagery is that you can access it much faster, since it has already been captured. However, it also has limitations. For example, you may not find imagery that meets your required acquisition date or coverage because no suitable imagery was captured during that period.

When Purchasing Archive Imagery Makes Sense

When you need data quickly, archive imagery can be a practical option because it's already captured and available for purchase.

If you need satellite imagery from a specific past date or period, archive imagery is the only option, provided suitable imagery is available. The available imagery should meet your resolution and quality requirements. If it does not, it may not suit the project.

In many cases, archive imagery can establish a baseline that helps geospatial teams compare more recent captures and identify changes over time. It is also useful for monitoring historical changes in a specific location.

Finally, archive imagery can be suitable when project requirements do not call for a new acquisition and existing imagery meets the required specifications.

What Is Tasking Satellite Imagery?

You can request satellite imagery after defining an AOI and specifying acquisition requirements, such as:

• Acquisition window
• Resolution
• Sensor type
• Viewing conditions

Providers review the request and determine whether they can fulfill the acquisition. The provider then schedules the acquisition based on satellite availability and operational constraints.

Compared with purchasing archive imagery, tasking generally takes more time because the imagery must be captured before it can be delivered.

When Tasking Satellite Imagery Makes Sense

When no suitable archive imagery is available, tasking may be the appropriate option for acquiring new imagery.

If you need imagery within a specific future acquisition window, or if existing imagery does not meet the required resolution or quality, you can request a new acquisition for your AOI with specified requirements, such as sensor type.

A project may also require specific acquisition conditions that are not available in existing imagery. In that case, tasking can provide an alternative that better matches the project requirements.

For monitoring projects that require repeated new captures, tasking can support regular data collection. For example, after a flood or wildfire, new captures can be compared with archive imagery that establishes a baseline of normal conditions for the area.

Archive vs. Tasking: Key Differences

This table summarizes differences between the two approaches:

| Factor | Archive Imagery | Tasking Imagery | | --- | --- | --- | | Acquisition | Already captured | New capture requested | | Availability | Depends on existing coverage | Depends on satellite availability | | Delivery time | Usually faster | Usually requires additional lead time | | Acquisition date | Limited to existing imagery | Specified within an acquisition window | | Historical analysis | Suitable for past dates | Not applicable for past dates | | Future acquisition | Not possible | Strong fit | | Image conditions | Already known | Can specify acquisition requirements | | Cost | Depends on imagery and provider | Depends on tasking requirements | | Risk of unsuitable conditions | Known before purchase | Conditions may affect successful acquisition |

What to Check Before Buying

Whether buying archived imagery or tasking new imagery, check these factors before completing the purchase.

Area of Interest (AOI)

The imagery should fully cover the area you are studying. Any missing sections or gaps can affect the project. So, before buying, check that the capture includes the entire AOI.

Acquisition Date

What do you need the imagery for? The answer determines the right date.

For example, you may need the imagery from a specific period to assess current conditions and compare changes over time.

Given that, always check that the capture date or acquisition window matches the project’s requirements.

Resolution

The imagery's GSD must be suitable for the intended analysis. Higher-resolution imagery is not necessarily the better option. Although it can reveal smaller features, a lower-resolution capture may be sufficient for broader area-level analysis.

Cloud Coverage

Cloud coverage can reduce the usable area of an optical image. The key point is that the overall cloud percentage does not always show how much of your AOI is affected.

For example, an image with low cloud coverage may still be unsuitable if clouds cover the specific area you need to analyze.

Off-Nadir Angle

Check that the off-nadir angle is within the project’s requirements to ensure accurate measurements or detailed analysis. A higher angle can affect the appearance and geometric accuracy of features in the image.

Sensor and Data Type

Different sensors capture different kinds of information. As a result, make sure the sensor and data type match the project’s requirements.

Licensing

Check that the imagery's license allows the intended use, including any requirements related to client projects or data distribution.

Delivery and Processing

The delivered data should be compatible with the project’s GIS and include the required information necessary for analysis. In particular, check:

• Available formats
• Processing level
• Metadata
• Delivery requirements

Source and Compare Imagery From Multiple Providers

Archive imagery can work when existing captures meet your needs, and tasking may be appropriate when available imagery is not helpful enough. In general, the project’s specific requirements are key factors in determining whether archive or tasking imagery is the right choice.

Even after learning which type of imagery you need, you still have to find a suitable option. Different providers offer different inventories and tasking capabilities, which can make the sourcing process more time-consuming.

You can use LandEye as a centralized marketplace that connects providers to buyers. This means you do not have to go through multiple provider catalogs on different platforms, which helps save time, especially if you work on multiple projects.

Compare archive and tasking options on LandEye now and explore your options.