Why are the features not as sharp in Planet data?
(1) Planet’s vision is to image the whole earth, every day. This vision depends on having many small satellites in orbit, and an intentional trade-off in frequency over spatial resolution. Planet data are captured at lower resolution than some data which Google and other map providers use in our basemaps. Planet captures at roughly 4 m resolution whereas some other providers capture at sub-meter.
Why does the image look spotty or have sharp lines?
(2) Planet uses “seasonal” imagery to create an interactive basemap layer. That means that users can switch between basemaps created from data collected at different times, for example a January basemap or a Q1 basemap. Within a certain time span, Planet’s automated mosaicking algorithm selects the best cloud and snow free data that it can, but in some areas, especially in high elevations and high latitudes, snow or clouds simply can’t be avoided for months on end. This has the effect of making some parts of the basemap look ‘stripey.’ The benefit in this scenario, however, is that this basemap data are guaranteed to fit within the specific time lapse selected.
Why are some of the pixels bright green or pink?
(3) In some cases, especially with very bright pixels, Planet data may be saturated and may appear green or pink. Planet has two different color balancing approaches: one does not have any pixel artifacts but will result in more scene lines and less tonal consistency. The other has the opposite effect: more saturation but fewer scene lines and more tonal consistency. Planet is actively working on techniques to find the best-of-breed solution to this problem.
Why do I see areas where there are no basemap images?
(4) Automated Timelapse Basemaps may have gaps in coverage if Planet was unable to acquire quality imagery within the specific time lapse period due to Planet coverage limitations, cloud cover, or other reasons. Planet will make best efforts to achieve full coverage in all cases but can not guarantee this.
Other basemap providers may be manually updating certain areas of the basemap over time. However it is not methodically updated in a published, traceable fashion, so it is not possible to know how old a certain pixel may be. Many images that you will see in Google maps, for example, could be up to several years old.
Why are things not showing up towards the North or South Pole?
(6) Due to orbital constraints and solar orientation relative to the surface at time of image capture, high latitude areas present far fewer opportunities for quality imaging. Planet incorporates usable data whenever possible.
Why do some pixels seem fuzzy?
(7) Outside of the natural appearance of 4-5 m data, some older Planet data may exhibit a lack of sharpness. Planet’s newer constellation has improved optics and onboard systems to improve the image quality. Planet will always use the most recent imagery when possible to create a basemap.
Why do some basemaps views include faint lines?
(8) Seam lines may be present in areas where scenes come from captures on different dates. Planet’s tonal balancing techniques attempt to minimize scene lines when possible but it is not always possible to remove all traces of these boundaries.
Why do some bodies of water appear poorly?
(9) All inland water bodies will contain valid imagery within a basemap. Some exceptions may be made on a per case basis for the largest of the global inland water bodies. All basemaps containing coastlines will contain water out to as far as 30 km from the main coastline, but the color balancing of that water can not be guaranteed.
Mosaics in areas with numerous small islands will contain valid imagery over the water that connects the islands up to a point where open water is reached, where coastline limitations (as described above) are then applied.
How are the basemaps assessed for quality?
All Planet Basemaps are quality checked through manual inspection processes that involve checking pre-identified high-value areas, and spot checking a fixed proportion of sites per square kilometer.
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