GetTile

The GetTile operation allows clients to request:

• a particular Tile
• of a particular layer
• of a particular tileMatrixSet
• in a particular format

The GetTile URL

The client can request a GetTile operation from the WMTS server in order to get the actual imagery Tile of a particular tileMatrixSet in a predefined format. This operation has some parameters in common with WMS GetMap but it has been deliberately simplified.

GetTile Request Parameters

The parameters required for the GetTile request are shown below. The client provides the following information in a Key-Value Pair (KVP) format, where the "name" field is the key, and the "value" field is the value; the data is supplied in the format "key=value"; for example, "service=WMTS".

The Format Parameter

The FORMAT parameter specifies the desired tile format of the response to a request operation. Not all layers are available in the same formats, check the capabilities document for allowed formats in different layers.

The Layer Parameter

This is a list of layers available in the capabilities document. Your account privileges determine which layers you may access.

The CQL_Filter Parameter

Catalog Query Language is a simple filter language loosely based on SQL. It is thus possible to perform simple comparisons ('=', '<', '<=', '>=','>','<>'), logic composition ('AND', 'NOT', 'OR') and string matching ("LIKE '%foo%').

The filter can use the attribute names as the finishedFeature WFS Feature type (e.g., Feature ID, dataLayer, source,...). Check a WFS GetFeature or DescribeFeatureType output for a full list of parameters, like the following:

The Bands Parameter

The bands parameter allows the client to perform on-the-fly false color image generation by picking 3 bands as R, G, and B from 8-band features. In order for this parameter to make sense a CQL_FILTER should be added that selects only the desired type imagery, for example, by selecting a specific feature by Feature ID using "CQL_FILTER=feature_id%3D%27<FeatureID>%27", and ensure that the feature you select has the appropriate product type (e.g., MS1_MS2, SWIR 8-band).

Examples of usage of the bands parameter are "bands=C,Y,RE" or "bands=S1,S4,S7".

For 8-band products, the band IDs and descriptions are:

For SWIR products, the bands IDs are S1, S2, S3, S4, S5, S6, S7.

GetTile Response

The response to a GetTile Request is a Map Tile in the requested format and projection. All image based WMTS Tiles are 256x256 pixels; no other Tile sizes are currently supported. Some specific formats might not have a corresponding Tile size notion (e.g., quantized mesh Tiles).

Exceptions

In the event that a WMTS encounters an error while processing a request or receives an unrecognized request, it will generate an XML document indicating that an error has occurred. An <ExceptionReport> element will contain one or more processing exceptions specified using the <Exception> element. Individual <Exception> elements contain exceptionCode, which specifies the actual exception that occurred.

The following example of an exception report indicates that a parameter value is missing and a parameter value is invalid in the request URL.

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<?xml version="1.0" encoding="UTF-8"?>
<ExceptionReport 
xmlns="http://www.opengis.net/ows/1.1"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.opengis.net/ows/1.1 owsExceptionReport.xsd" version="1.0.0" xml:lang="en">
    <Exception exceptionCode="MissingParameterValue" locator="service"/>
    <Exception exceptionCode="InvalidParameterValue" locator="version"/>
</ExceptionReport>