Gibs api for developers – global imagery browse services – gibs – earthdata wiki electricity in the 1920s

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The Global Imagery Browse Services (GIBS) are designed to deliver global, full-resolution satellite imagery to users in a highly responsive manner, enabling interactive exploration of the Earth. To achieve that interactivity, GIBS first ingests imagery from a given NASA data provider on a continuous basis, creates a global mosaic of that imagery, then chops the mosaic into an image tile pyramid (see figure below). By pre-generating these tiles, it relieves the servers of image rescaling and cropping duties, greatly reducing computational overhead and enabling a highly responsive system. This also means that the primary method of imagery retrieval for clients is tile-based. For more background on how tiled web maps work, see the MapBox Developers Guide.

While the requests made to GIBS are for individual tiles, users generally work at a higher level and configure a map library, GIS client, or script to determine which tiles to retrieve. electricity symbols ks2 worksheet These clients and scripts need to know which products are available, which map projections are available, and how many zoom levels they support. GIBS provides this access through five mechanisms:

The Open Geospatial Consortium (OGC) Web Map Tile Service (WMTS) provides a way for clients to retrieve tiled mapping data in a standardized manner, handling product-specific details such as available number of zoom levels, map projections, image formats, tile sizes, etc. The WMTS specification provides guidance for three methods of tile retrieval: Key-Value Pair (KVP), REpresentational State Transfer (REST), and Simple Object Access Protocol (SOAP). GIBS supports KVP and REST, but not SOAP. Service Endpoints and GetCapabilities

The core concept within the GetCapabilities response is a map layer. GIBS map layers represent data that changes over time, most commonly providing a different map each day. Therefore, the layer definition within the GIBS GetCapabilities response must present a time dimension. The GIBS team has chosen to address this in the following manner, within each layer:

If the time dimension is omitted in the WMTS request, GIBS will return tiles for the default date, as specified in the tag. Note that GIBS’ imagery layers all have a value of false in the tag which means that the special current keyword cannot be provided as the time value. 3 gases However, GIBS does support use of the special default keyword, which results in the same response as though the date were omitted. Sample Execution

The Open Geospatial Consortium (OGC) Web Map Service (WMS) provides a way for clients to receive a customized WMS response based on request parameters such as a custom bounding box, dimensions, layer(s) and format. Unlike the rigidity enforced through tiled interfaces (e.g. WMTS and TWMS), WMS responses are more flexible and may contain multiple composited layers in a single output. Two WMS specifications are currently available and supported by GIBS: 1.1.1 and 1.3.0. Both WMS specifications support a single method of tile retrieval, which is supported by GIBS: Key-Value Pair (KVP). electricity physics formulas Service Endpoints and GetCapabilities

The core concept within the GetCapabilities response is a map layer. GIBS map layers represent data that changes over time, most commonly providing a different map each day. gas welder job description Therefore, the layer definition within the GIBS GetCapabilities response must present a time dimension. The GIBS team has chosen to address this in the following manner, as outlined in the respective OGC WMS specification:

If the time dimension is omitted in the WMS request, GIBS will return tiles for the default date, as specified in the default attribute. Note that GIBS’ imagery layers all have a value of 1 in the nearestValue tag indicating that GIBS will snap to the nearest time value within the specified dimension extents. Additionally, GIBS supports use of the special default keyword, which results in the same response as though the date were omitted. Sample Execution

Those patterns are described in the TWMS GetTileService request. The response is an XML encoded list of available WMS access patterns. A TiledPattern access pattern is a set gridded WMS requests, where parameter order, case and content are constant, with the exception of the bbox values. Using this pattern allows fast access to tiles for a given combination of layers and associated styles at a given resolution over a defined area. All the information about a pattern can be extracted form the provided WMS call, using these rules:

Server prefix is defined in the OnlineResource tag Area covered is defined in the LatLonBoundingBox Tile size is provided by the width and height parameters values Tile format is provided by the format parameter value Tile coverage can be computed as (Lon1-Lon0)and (Lat1-Lat0), where Lon1,Lon0,Lat1 and Lat0 are the arguments of the bbox parameter. The Grid alignment results from the bbox argument and the tile coverage. The bbox argument values provided in the pattern are for the top-left tile, the other tile locations can be computed based on the tile coverage. electricity and magnetism equations Other metadata that might be of interest to a user is contained in the Name, Title and Abstract tags.

Multiple WMS patterns in a single TilePattern are equivalent. TilePattern tags that have something in common are grouped in a hierarchical structure build using TiledGroup tags. The innermost level refers to the same exact data, possible differences being the image size, image format, resolution, and alignment. Higher level TiledGroup are used to group together related datasets.

A client application is expected to request this information only if it is defined as a request in the WMS server Capabilities. Once obtained, the application needs to analyze the patterns, decide which ones can be used and then issue only WMS requests that match the pattern to the normal WMS server, requests that can be built by modifying the bbox argument in a TiledPattern and prefixing the resulting string with the content of the OnlineResource tag.

The ‘time’ parameter follows the form YYYY-MM-DD which should be included in the request for a time-varying layer; if the time dimension is omitted in the TWMS request, tiles for the current UTC date will be returned. Be aware that many of the current date’s tiles will be empty because the imagery is generated as the satellites orbit from east to west. Service Endpoints

Google Earth KML files can be generated on-the-fly for all tiled products served by GIBS. The returned KML file contains NetworkLinks to the GIBS server – this means that when the KML file is loaded within Google Earth, a full globe’s imagery is available, though only the relevant tiles are retrieved based on your current viewpoint. In short, the KML file directly maps data access to the Tiled WMS request patterns. gas laws definition chemistry Service Endpoint

The Geospatial Data Abstraction Library ( GDAL ) WMS driver supports several internal ‘minidrivers’ that allow access to different web mapping services. Each of these services may support a different set of options in the Service block. cheapest gas in texas Documentation for these minidrivers can be found here on the GDAL website. Two of these minidrivers in particular can be used by users to download GIBS imagery programmatically. They are the Tile Map Specification (TMS) and the OnEarth Tiled WMS (TiledWMS) minidrivers. For more information and examples regarding interacting with the GIBS API through these GDAL minidrivers, refer to our Map Library Usage wiki page. Bulk Downloading

A "Bulk Download" is defined as the planned retrieval of more than 1,000,000 imagery tiles within a 24 hour period. These activities are typically orchestrated through script-based access to the GIBS API, not user-based access through a client application. In order to ensure quality of service for all GIBS users, the GIBS team requests that bulk downloading activities be coordinated at least 48 hours in advance of the planned download. Prior to beginning your bulk downloading activities, please contact the GIBS support team at support@earthdata.nasa.gov with the subject "GIBS Bulk Download Request" and the following information: