Frequently Asked Questions
Listed below are some frequently asked questions regarding satellite imagery and the Arlula API product. If you have any issues with the Arlula API and your questions aren’t answered below, please feel free to contact our support team here.
Ultimately what a satellite image allows us to see will depend on factors such as resolution, sensor type, processing and application. But from a fundamental level, satellite imagery provides a valuable overview of our planet and can provide insights for a broad range of industries and use cases. Satellite imagery can also provide information beyond what can be seen on the Earth’s surface, and when integrated with other data types can help us learn an enormous amount about our work and community.
Novel use cases for satellite imagery are growing at an ever increasing rate and include inventory and resources management, crime mapping, establishing and monitoring transport routes, managing networks, asset monitoring, property development and planning, agricultural crop health and harvesting, public health, fire risk monitoring, invasive species monitoring, smart city planning and monitoring, illegal fishing and border control. If you’d like to learn more about satellite imagery use cases and how it can solve problems for you, please don’t hesitate to contact us.
As with all data, the more granular it is the more detail it will contain. Satellite imagery works in the same way. Higher resolution imagery will contain more details than lower resolution imagery and as a result more detailed and accurate insights can be derived. Resolution isn’t everything though, and often the type of sensors is just as important. If you’re unsure what resolution or type of imagery you need for your project please feel free to contact us.
Arlula provides access to a range of satellite imagery sensor types offered by our global network of suppliers. Currently the Arlula API provides direct access to Multispectral imagery of different resolutions, but other sensor types can be accessed by contacting us directly.
Multispectral images consist of reflected energy from several spectral bands and can produce images that look like regular colour photography. In reality, individual bands can provide more insights that can be seen by the naked eye and are valued differently according to the specific use case. Generally speaking, more spectral bands means more data and the potential for a greater variety of insights and use cases.
Panchromatic imagery has a grayscale appearance due to the single band used to capture data and merge a range of individual visible light spectrums and wavelengths. The advantage of this is that it produces a much higher spatial resolution and can often produces near infrared depending on the specific sensitivity of the sensor.
If needed, a simple way to find geographic coordinates is by using Google maps. Begin by locating your area of interest by using the search bar, then click on part of the map with the cursor to reveal a latitude and longitude.
With regards to satellite imagery, a EULA is a contract between the imagery supplier and the imagery purchaser/user. It provides the terms by which the image can be used and often includes restrictions regarding types of permitted usage, seats and responsibilities of each party. Arlula provides customers with the standard EULA offered by each of the imagery’s respective supplier and must be agreed to before purchasing and using the image. This is a standard industry practice and Arlula’s supplier EULA’s can be viewed individually here. If you have any further questions about EULA’s please don’t hesitate to contact us.
Arlula drastically reduces the time it takes for users to search, order and receive satellite imagery. The turnaround time from placing an order to delivery is dependant on each imagery supplier, and ranges from instant to 5 day turnaround times.
The Arlula API provides users with an estimated fulfilment time for each individual supplier, so users can take this into consideration when choosing imagery they want to order. This can be found under the fulfillment Response Parameter. Please view our documentation for more details.
User seats relate to the End User License Agreement (EULA) provided by each individual imagery supplier. More specifically, it is the number of active users permitted to use a specific satellite image order.
Using the API
Using the Arlula API is completely free. The only costs associated with the Arlula API is if you choose to purchase commercial grade satellite imagery. Alternatively, you are free to use Government imagery from satellites such as Landsat at no cost.
Yes, the Arlula API Python Package can be viewed and downloaded here.
Coverage of specific areas vary greatly between suppliers, and not all suppliers have coverage for all locations, for all time periods you may be interested in. Additionally, during periods of high traffic, some suppliers may return an empty response to alleviate load. If you are certain there should be coverage, please try again at a later time or contact our support team.
AOI pricing may not be available for a variety of reasons, common reasons include:
- Your search was a point search and not a bounding box.
- The supplier for that image does not support AOI ordering (common for free imagery sources like Landsat).
- The overlap of your AOI and the scene is less than the supplier’s minimum order (varies by supplier, but generally 25 km2).
- The width of the overlap may not meet the suppliers minimum swath requirements (not applicable for all suppliers, and varies between them).
Most situations that will cause AOI pricing to not be included (other than a point search) will be noted in the search result’s ‘annotations’ field if you need to check the specific cause.
While we endeavour to provide accurate estimates for how long a supplier will take to fulfil their order, this can sometimes take longer than we expect. We ask that you please be patient with us while we wait for the supplier’s response. If the order is overdue by more than double the quoted time, please contact our support team for further information.
Pricing varies by supplier, but generally, it’s based on a rate per square kilometer of imagery covered (with some minimums and requirements for ordering). When looking at a search result, scene pricing is the price to purchase a whole image capture (the whole area shown in the thumbnail), this can be significant for large scenes.
If you have searched for a bounding box as an area of interest, and the area of interest meets the suppliers requirements within that scene, a second set of pricing is available to only purchase the part of the scene that is your AOI. In this case the AOI pricing will be to only purchase the part of the scene that overlaps with your AOI.
The overlap field of search results is only available when searching for a bounding box area of interest. When present, it contains details of the portion of the scene that is your area of interest. The Area field is the area of the scene that is part of your AOI (the overlap with your AOI)
Percent is a little different. Percent is the % of your total search AOI that this overlap satisfies (i.e. if you did a very large search and you may include most of the scene, but it may only be 25% of your search area).
If you’re using the Arlula API, once your order is ready (in the ‘complete’ status), imagery resources will be listed when you retrieve the order via the get order endpoint. To retrieve a particular imagery file, you will then need to make a request to the get order resource endpoint with the resources ID.If not using the Arlula API, we will deliver the imagery to you via ftp or a specific method agreed to during the order
The precise combination of files will differ by supplier, but the imagery will be made available as GeoTIFF files, generally split up into several GeoTIFF files, one per imagery layer. Additional files such as GDAL and other metadata formats will also be present, but differ by supplier.