Glossary
Welcome to the glossary for the SatVu platform. This section is designed to help you become familiar with key terms and concepts used across the platform, as well as terms related to geospatial technology, remote sensing and thermal imaging.
| Term | Definition |
|---|---|
| AOI | An Area of Interest (AOI) is a specific geographic area defined by coordinates or boundaries, which is the focus for data collection. |
| API | The Application Programming Interface (API) is a set of tools and protocols that allow different software applications to interact with the SatVu platform through a set of endpoints. The SatVu platform includes a RESTful API. |
| Azimuth | From the scene target point on the ground, the Azimuth is the angle between true north and the sub-satellite point / nadir (point on the ground directly below the satellite). Measured clockwise from north in degrees (0-360) |
| Catalog | The catalog consists of high-resolution thermal data previously collected by SatVu and platform users’ past tasking orders. With access to the catalog, users are able search all available data based on image metadata, select a specific scene or selection of scenes and place an order to access the data. |
| Catalog Item | A catalog item is the term used to describe a single data capture. It aligns with the definition of a STAC item, which represents a single spatiotemporal asset described with specified metadata. |
| Cloud cover (%) | The percentage of the scene obscured by clouds. Cloud cover can affect the quality and usability of satellite images. |
| Contract | A contract is the formal agreement between SatVu and the user outlining terms of service, data access, and usage rights. This includes defining which aspects of the platform a user has access to and who in the organisation has access to the SatVu platform. Within the SatVu platform, users must select a valid contract in order to make catalog orders or place tasking orders. Each contract has agreed start & end dates, prices for each data product and a credit limit. |
| Elevation | The angle of the object (such as the satellite) above the horizon from the perspective of the target point of the scene. It is measured from the horizon in degrees (-90 to 90), with negative values indicating the object is below the horizon |
| EULA | End User License Agreement - A legal contract between the provider of software or data and the user, outlining the rights and restrictions associated with the usage of the product. |
| Feasibility check | A feasibility check is the process of evaluating if the tasking order with provided parameters can be captured. The check enables better planning of acquisitions by evaluating the current satellite position, its orbit, weather conditions and other forms of data to inform if the tasking order will likely be successful |
| Footprint | The ground area covered by a satellite image at any given time. It is represented by a polygon geometry, commonly defined by its swath width and length. |
| Geocoding | The process of converting addresses or other descriptive locations into geographic coordinates that can be used to place the information on a map. |
| GeoJSON | GeoJSON is an open standard format for communicating geospatial data. It is based on the JSON format, often used in web applications for mapping and spatial data exchange. |
| Georeferencing | Georeferencing is the process of relating the coordinate system of an image to a geographic coordinate system, which allows you to see the image in its correct location on the globe. |
| Geospatial data | Information associated with a specific location on the Earth's surface, including coordinates, maps, and satellite imagery. |
| GeoTIFF | Geographic Tagged Image File Format (GeoTIFF) is a file format which is widely used for Earth observation data because it allows spatial information to be included with raster data. SatVu imagery is delivered in Cloud Optimised GeoTIFF (COG) format - a type of GeoTIFF file format which is optimised for use in the cloud. It allows faster data visualisation and streamlined geospatial processing workflows. |
| GIS | A Geographic Information System (GIS) is a computer system used to analyse and display any geographically referenced information. It is commonly used to visualise and analyse map data and images related to positions on the Earth’s surface. |
| Ground Sample Distance (GSD) | Ground Sample Distance is the distance between two consecutive pixel centres measured on the ground. It is impacted by the off-nadir angle, with a higher off-nadir angle resulting in a higher GSD. |
| Ground Station | A facility equipped to receive data from and communicate with satellites, often used for downloading satellite imagery and other data. |
| Ground Station Network (GSN) | A network of ground stations that provide global coverage for receiving satellite data and managing satellite communications. |
| Image Metadata | Image Metadata is the information that describes the content, quality, condition, and other characteristics of the geospatial data, helping users understand and use the data appropriately. The image metadata provided with SatVu images is in line with STACspecifications. |
| MWIR (Mid-wave infrared) | Mid-wave infrared (MWIR) is the portion of the electromagnetic spectrum which contain the SatVu imaging wavebands of 3.7-5 μm at night and 4.5-5 μm during the day. |
| Nadir | Nadir represents the point directly below the satellite, where the sensor is looking straight down at the Earth's surface |
| Off Nadir Angle | The angle between the nadir (directly below the satellite) and the point on the ground being imaged, used to describe the sensor's position relative to nadir. |
| Order | An order represents a customer request for imagery from the SatVu platform. This could be an order from the Catalog, or a Tasking order. Each order has a unique ID and can be viewed or managed in the SatVu platform. Standard tasking orders may belong to a recurring order Series. |
| Recurring order series | A recurring order series (or Series) is a parent grouping of multiple standard tasking orders placed at once over the same location, each covering a repeating time window. The series defines the recurrence schedule, and each individual occurrence within it is a fully independent tasking order with its own ID and status. |
| Orthorectification | The process of correcting the sensor, satellite/aircraft motion and terrain-related geometric distortions in satellite or aerial imagery to accurately represent the Earth's surface. |
| PNG | Portable Network Graphics (PNG) is a widely used image storage format which can be easily viewed across a range of computer operating systems |
| POI | The Point of Interest (POI) is the specific location or feature on the Earth’s surface that is of interest within a scene, or for tasking the satellite. |
| Raster Data | Geospatial data represented by a grid of cells or pixels, where each cell contains a value representing specific information, such as thermal signature. |
| Scene | A single image or frame captured by a satellite or sensor, characterised by a specific AOI at a given time. |
| SDK | A Software Development Kit (SDK) is a collection of software tools and libraries that developers can use to build applications for specific platforms or systems. The SatVu SDK is built in the Python programming language to simplify interaction with the platform through Python. |
| Spatial Resolution | The size of the smallest object that can be detected in an image, where higher resolution means finer detail. For satellite imagery, the spatial resolution is often represented by the Ground Sample Distance (GSD) - the distance between two consecutive pixel centres measured on the ground |
| Spectral Resolution | The ability of a sensor to distinguish between different wavelengths of light, allowing for the identification of various materials or phenomena. The SatVu sensor captures the mid-wave infrared (MWIR) region of the electromagnetic spectrum, capturing radiation in the range of 3.7-5 μm at night and 4.5-5 μm during the day. |
| STAC | STAC is a standard specification used to store and describe geospatial information. The SatVu image metadata uses the STAC specification so that it can be worked with, indexed and discovered easily and in a consistent manner. |
| Sun azimuth | From the scene target point on the ground, this is the angle between truth north and the sun. Measured clockwise from north in degrees (0-360). |
| Sun elevation | The angle of the sun above the horizon from the perspective of the target point of the scene. It is measured from the horizon in degrees (-90 to 90), with negative values indicating the sun is below the horizon |
| Tasking | Satellite tasking is the process of requesting a new image collection. Users can task SatVu to capture a new image by specifying a location, time frame and other parameters. The SatVu platform provides a transparent price estimation, a straightforward feasibility check, intuitive order monitoring, and fast data delivery. |
| Temporal Resolution | The frequency at which data is captured over the same area; higher temporal resolution allows for more frequent monitoring of changes over time. |
| Thermal Imagery | Imagery that captures the infrared radiation emitted by objects, used to measure differences in thermal signatures on the Earth's surface. |
| Vector Data | Geospatial data represented by points, lines, or polygons, used to model real-world features like cities, roads, and boundaries. |