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GetFeatureInfo in WMS using a box?


I'm using this WMS service http://www.cartografiarl.regione.liguria.it/mapfiles/repertoriocartografico/LAVORIINCORSO/1633.asp?REQUEST=GetCapabilities&SERVICE=WMS&VERSION=1.3.0&

I can query it using GetFeatureInfo in a WMS request like this one: http://www.cartografiarl.regione.liguria.it/mapfiles/repertoriocartografico/LAVORIINCORSO/1633.asp?&LAYERS=L4313&QUERY_LAYERS=L4313&STYLES=&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&BBOX=1018299.271264%2C5479845.539429%2C1123018%2C5492228.338009&FEATURE_COUNT=10&HEIGHT=162&WIDTH=1370&FORMAT=image%2Fpng&INFO_FORMAT=application%2Fvnd.ogc.gml&SRS=EPSG%3A3857&X=891&Y=22&

The response is:

1086509.551130,5490410.633321 1086509.551130,5490410.633321 4 011023_002 Riccò Del Golfo Via Aurelia, Snc 03 immobile destinato autorimessa 1 21/10/05 altre associazioni a delinquere 03 destinato 19/07/2007 02 Comune istituzionali PRO_ciuffardi_paolo.pdf 011023_002_F.pdf 1086505.336252,5490406.481274 1086505.336252,5490406.481274 3 011023_001 Riccò Del Golfo Via Aurelia, Snc 03 immobile destinato appartamento 1 21/10/05 altre associazioni a delinquere 03 destinato 19/07/2007 02 Comune sociali PRO_ciuffardi_paolo.pdf 011023_001_F.pdf

Now I'd like to do the same request but for a bigger BBOX for example http://www.cartografiarl.regione.liguria.it/mapfiles/repertoriocartografico/LAVORIINCORSO/1633.asp?&LAYERS=L4313&QUERY_LAYERS=L4313&STYLES=&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetFeatureInfo&BBOX=832454%2C5423777%2C1118664%2C5564559&FEATURE_COUNT=100&HEIGHT=162&WIDTH=1370&FORMAT=image%2Fpng&INFO_FORMAT=application%2Fvnd.ogc.gml&SRS=EPSG%3A3857&X=891&Y=22&

I receive no response and no error… Too big the bbox?


The X and Y coordinates in the GetFeatureInfo query mean the pixel coordinates of the image that is created with the GetMap parameters which are included in the request. You can't change the BBOX parameters independently from the X and Y parameters and suppose that the result would be the same.

In your first case the request contains these parameters for the GetMap query

BBOX=1018299.271264,5479845.539429,1123018,5492228.338009 WIDTH=1370&&HEIGHT=162

GetFeatureInfo request it using parameters X=891&Y=22 which means "891 pixels to the left and 22 pixels down from the top left corner (min easting, max northing) of the map".

In your first case

Top-left: 1018299,5492228 Pixel size W-E: (1123018-1018299)/1370 = 76.43722628 Pixel size N-S: (5492228-5479845)/162 = 76.43722628 Coordinates at image coordinates 891,22 = 1086404.569,5490546.358

In the second case

Top-left: 832454,5564559 Pixel size W-E: (1118664-832454)/1370 = 208.9124088 Pixel size N-S: (5564559-5479845)/162 = 869.0246914 Coordinates at image coordinates 891,22 = 1018594.956,5545440.457

In the image below you can see the both BBOXes and query points. There is no data in the query point 2 and therefore you are getting an empty result.


GetMap¶

In the WMS GetMap request, QGIS Server accepts a couple of extra parameters in addition to the standard parameters according to the OGC WMS 1.3.0 specification:

DPI parameter: The DPI parameter can be used to specify the requested output resolution.

IMAGE_QUALITY parameter is only used for JPEG images. By default, the JPEG compression is -1 . You can change the default per QGIS project in the OWS Server ‣ WMS capabilities menu of the Project ‣ Project Properties dialog. If you want to override it in a GetMap request you can do it using the IMAGE_QUALITY parameter:

image/png mode= can be used to override the png format. You can choose between image/png mode=16bit , image/png mode=8bit and image/png mode=1bit . This can shrink the output image size quite a bit. Example:

OPACITIES parameter: Opacity can be set on layer or group level. Allowed values range from 0 (fully transparent) to 255 (fully opaque).

FILTER parameter: Subsets of layers can be selected with the FILTER parameter. Syntax is basically the same as for the QGIS subset string. However, there are some restrictions to avoid SQL injections into databases via QGIS server:

Text strings need to be enclosed with quotes (single quotes for strings, double quotes for attributes) A space between each word / special character is mandatory. Allowed Keywords and special characters are ‘AND’,’OR’,’IN’,’=’,’<’,’>=’, ‘>’,’>=’,’!=*,’(‘,’)’. Semicolons in string expressions are not allowed

It is possible to make attribute searches via GetFeatureInfo and omit the X/Y parameter if a FILTER is there. QGIS server then returns info about the matching features and generates a combined bounding box in the xml output.

SELECTION parameter: The SELECTION parameter can highlight features from one or more layers. Vector features can be selected by passing comma separated lists with feature ids in GetMap and GetPrint .

The following image presents the response from a GetMap request using the SELECTION option e.g. http://myserver.com/. &SELECTION=countries:171,65 . As those features id’s correspond in the source dataset to France and Romania they’re highlighted in yellow.

Server response to a GetMap request with SELECTION parameter

It is possible to export layers in the DXF format using the GetMap Request. Only layers that have read access in the WFS service are exported in the DXF format. Here is a valid REQUEST and a documentation of the available parameters:

  • FORMAT=application/dxf
  • FILE_NAME=yoursuggested_file_name_for_download.dxf
  • FORMAT_OPTIONS=see options below, key:value pairs separated by Semicolon
  • SCALE:scale to be used for symbology rules, filters and styles (not an actual scaling of the data - data remains in the original scale).
  • MODE:NOSYMBOLOGY|FEATURESYMBOLOGY|SYMBOLLAYERSYMBOLOGY corresponds to the three export options offered in the QGIS Desktop DXF export dialog.
  • LAYERSATTRIBUTES:yourcolumn_with_values_to_be_used_for_dxf_layernames - if not specified, the original QGIS layer names are used.
  • USE_TITLE_AS_LAYERNAME if enabled, the title of the layer will be used as layer name.

GetFeatureInfo¶

QGIS Server WMS GetFeatureInfo requests supports the following extra optional parameters to define the tolerance for point, line and polygon layers:

  • FI_POINT_TOLERANCE parameter: Tolerance for point layers GetFeatureInfo request, in pixels.
  • FI_LINE_TOLERANCE parameter: Tolerance for linestring layers GetFeatureInfo request, in pixels.
  • FI_POLYGON_TOLERANCE parameter: Tolerance for polygon layers GetFeatureInfo request, in pixels.

GetPrint¶

QGIS server has the capability to create print composer output in pdf or pixel format. Print composer windows in the published project are used as templates. In the GetPrint request, the client has the possibility to specify parameters of the contained composer maps and labels.

The published project has two composer maps. In the GetProjectSettings response, they are listed as possible print templates:

The client has now the information to request a print output:

Parameters in the GetPrint request are:

  • <map_id>:EXTENT gives the extent for a composer map as xmin,ymin,xmax,ymax.
  • <map_id>:ROTATION map rotation in degrees
  • <map_id>:GRID_INTERVAL_X, <map_id>:GRID_INTERVAL_Y Grid line density for a composer map in x- and y-direction
  • <map_id>:SCALE Sets a mapscale to a composer map. This is useful to ensure scale based visibility of layers and labels even if client and server may have different algorithms to calculate the scale denominator
  • <map_id>:LAYERS, <map_id>:STYLES possibility to give layer and styles list for composer map (useful in case of overview maps which should have only a subset of layers)

GetLegendGraphics¶

Several additional parameters are available to change the size of the legend elements:

  • BOXSPACE space between legend frame and content (mm)
  • LAYERSPACE versical space between layers (mm)
  • LAYERTITLESPACE vertical space between layer title and items following (mm)
  • SYMBOLSPACE vertical space between symbol and item following (mm)
  • ICONLABELSPACE horizontal space between symbol and label text (mm)
  • SYMBOLWIDTH width of the symbol preview (mm)
  • SYMBOLHEIGHT height of the symbol preview (mm)

These parameters change the font properties for layer titles and item labels:

  • LAYERFONTFAMILY / ITEMFONTFAMILY font family for layer title / item text
  • LAYERFONTBOLD / ITEMFONTBOLD ‘TRUE’ to use a bold font
  • LAYERFONTSIZE / ITEMFONTSIZE Font size in point
  • LAYERFONTITALIC / ITEMFONTITALIC ‘TRUE’ to use italic font
  • LAYERFONTCOLOR / ITEMFONTCOLOR Hex color code (e.g. #FF0000 for red)
  • LAYERTITLE / RULELABEL (from QGIS 2.4) set them to ‘FALSE’ to get only the legend graphics without labels

Contest based legend. These parameters let the client request a legend showing only the symbols for the features falling into the requested area:

  • BBOX the geographical area for which the legend should be built
  • CRS / SRS the coordinate reference system adopted to define the BBOX coordinates
  • WIDTH / HEIGHT if set these should match those defined for the GetMap request, to let QGIS Server scale symbols according to the map view image size.

Contest based legend features are based on the UMN MapServer implementation:

GetProjectSettings¶

This request type works similar to GetCapabilities, but it is more specific to QGIS Server and allows a client to read additional information which is not available in the GetCapabilities output:

  • initial visibility of layers
  • information about vector attributes and their edit types
  • information about layer order and drawing order
  • list of layers published in WFS

Using hale»connect resources in ArcGIS Online

Both open source and proprietary geographic information systems currently offer limited out-of-the-box support for complex GML. For a more in depth discussion of GML support in GIS software, visit the CanIUse INSPIRE github repository. Harmonized INSPIRE data is complex GML and this tutorial aims to demonstrate how hale»connect WMS services can be viewed in ArcGIS Online.

The Esri WFS implementation in ArcGIS Online only supports basic OGC WFS at the simple features level.

  • the current version of ArcGIS Online (April 2019). A valid Esri account is required to log-in to ArcGIS Online. You can create an Esri account on the Esri website for free.

Viewing a WMS

In order to view your hale»connect WMS in ArcGIS Online, you will need a URL link to the capabilities document of your service. You can directly access the capabilities documents for WMS 1.1.1 and 1.3.0 from the View Services section of your dataset. To copy any URL to the clipboard, click the icon to the right of the URL.

Login to ArcGIS Online and navigate to My Map. Click on the Add tab at the top left of the application.

From the Layer menu, select Add layer from the Web. In the Add layer from the Web dialog, select WMS-OGC-Web-Service as service type in the dropdown menu and enter the URL of your WMS capabilities document. Click Add layer.

Your WMS layer should appear in the layers panel on the left. Left click on the three dots which appear under the WMS name to view the options menu. The menu includes a range of options, such as zoom, transparency, rename and the option to further refine your OGC WMS request parameters.

Next, click on the black arrow next to the WMS name. Your WMS layer should appear. Left click on the three dots which appear under the layer name to activate pop-ups.

Once you activate pop-ups for your layer, the GetFeatureInfo response will display in the pop-up dialog for any feature that you click. If you click on an area with overlapping features, results for each feature will be listed. hale»connect services provide the unique ability to explore complex GML through the hale»connect FeatureExplorer. In the pop-up dialog in ArcGIS Online, click on the Details anzeigen button for the feature you are interested in.

The hale»connect FeatureExplorer will open in a new tab in your browser. The FeatureExplorer enables you to navigate through any level of nested, complex GML to further investigate the linked resources, linked features, codelists or attributes that you are interested in.

Learn more

For more information about ArcGIS Online, visit the Esri website.

ArcGIS Online maintains it’s own Resource pages. For more information about using OGC services in ArcGIS Online visit the ArcGIS Online OGC support pages.


Web Feature Service (WFS)

Information comes from documents found on the following webpage: http://www.opengeospatial.org/standards/wfs. The document is titled: OpenGIS Web Feature Service (WFS) Implementation Specification and is version 1.1.0.

A WFS is a web-based service that creates spatial data through requests to service URLs. However, unlike WMS, the WFS returns non-graphical documents representing spatial data encoded in the Geography Markup Language (GML - more information here). According to the specification, a WFS must have the following capabilities:

  1. interfaces are defined in XML
  2. GML is used to define features returned from the query
  3. the filtering/predicate language is defined in XML that is derived from CQL (common query language or contextual query language - more information here: http://www.loc.gov/standards/sru/specs/cql.html)
  4. the datastore should be accessed only through the WFS interface
  5. XPath expressions are use to reference properties
  • Keep in mind that WFS does not return images. WFS returns data encoded in GML which can be used on the client-side to create visual representations.

WFS Operations

WFS supports more types of operations than WMS and due to the relationship between the datastore and the WFS representation there are methods to interact directly with persistent storage. Supported operations include:

  • Transaction-based
    • insert - inserting new features into the datastore through the WFS interface
    • update - updating values in a datastore
    • delete - deleting features

    Features in a WFS are considered to be sets of properties that define a particular real-world object. Features are stored as tuples in the datastore - e.g. (id, wind_mph, wind_degrees).

    There are basically three types of WFS according to the specifications:

    1. Basic WFS - implementing a subset of potential operations including GetCapabilities, DescribeFeatureType and GetFeature. A basic WFS does not allow editing of features.
    2. XLink WFS - this type supports everything available in basic WFS but adds GetGMLObject methods
    3. Transaction WFS - supports all WFS functions - features can be edited by authorized users

    WFS example queries

    Following are examples of WFS queries. Note: these queries are conducted on the same datasets used in the WMS queries.

    GetCapabilities:

    The following query requests the capabilities of the same server used in the WMS examples previously.

    GetFeature

    GetFeature (2)

    • example query: http://localhost:8080/geoserver/opengeo/ows?service=WFS&version=1.0.0&request=GetFeature&typeName=opengeo:radial_1366208927&maxfeatures=50&outputformat=json
    • returns: JSON representation of features in radial_1366208927 layer
    • parameters:

    DescribeFeatureType

    Queries in a WFS environment can be much more complex and might be conducted through a POST request similar to the following example:

    • GET example query: http://epscor2.cgrer.uiowa.edu:8080/geoserver/wfs?service=wfs&version=1.1.0&request=GetFeature&typeName=opengeo:metars&featureID=metars.23
    • returns: GML representation of selected feature
    • parameters: in this case, the feature that is returned is the 23rd record in the datastore: <ogc:FeatureId fid="metars.23"/>

    Using hale»connect resources in QGIS

    Both open source and proprietary geographic information systems currently offer limited out-of-the-box support for complex GML. Simple viewing of vector geometry and associated attribute data is supported by some GISs, such as QGIS, however standard geoprocessing operations and spatial analyses are not supported for complex GML. For a more in depth discussion of GML support in GIS software, visit the CanIUse INSPIRE github repository. Harmonized INSPIRE data is complex GML and this tutorial aims to demonstrate how hale»connect view and download services can be loaded in QGIS.

    • the current version of QGIS 3.6.1 ‘Noosa’ which was released on 22.03.2019
    • the current version of the QGIS GML Application Schema Toolbox plugin 1.2.0

    Viewing a WMS

    In order to view your hale»connect WMS in QGIS, you will need a URL link to the capabilities document of your service. You can directly access the capabilities documents for WMS 1.1.1 and 1.3.0 from the View Services section of your dataset. To copy any URL to the clipboard, click the icon to the right of the URL.

    Open QGIS and click on the Layer menu. From the Layer menu, select Add Layer and then select Add WMS/WMTS Layer.

    In the Data Source Manager dialog, click the New button. This opens a dialog which allows you to define a new WMS connection. Give your new connection a name, and enter the URL to your hale»connect service in the URL field. Click OK.

    Your new layer should appear at the top of the Data Source Manager. Click the Connect button to access the service. You can select one or more layers to add to your map. Click on the Layer Order tab in the Data Source Manager dialog to control the drawing order of your layers. When you are finished, click the Add button in the bottom right corner of the Data Source Manager dialog to add the data to your map.

    The layers you select should appear in the layers panel on the left. QGIS displays the legend received from the GetLegendGraphic request made to the WMS. Right click on a layer and select Properties to view more information about the service.

    Identifying features in a WMS

    Once you have added your view service layers to the map, you can explore them using the Identify button.

    Click on the Identify button. In a standard QGIS installation, the button is found in the top row of toolbars. It is marked with an info symbol and white arrow. First, click on the Identify icon. Next, click on the layer you want to explore in the Layer panel on the left. Next, click on a feature in the map. The Identify Results panel containing the GetFeatureInfo response will appear to the right. If you click on an area with overlapping features, results for each feature will be listed. hale»connect services provide the unique ability to explore complex GML through the hale»connect FeatureExplorer. In the Identify Results panel in QGIS, click on the Details anzeigen button for the feature you are interested in. The hale»connect FeatureExplorer will open in a new dialog in QGIS. The FeatureExplorer enables you to navigate through any level of nested, complex GML to further investigate the linked resources, linked features, codelists or attributes that you are interested in.

    Viewing a WFS

    In order to view a WFS based on complex GML in QGIS, you need to first install the QGIS GML Application Schema Toolbox plugin.

    Installing the GML Application Schema Toolbox plugin

    Open QGIS and click on the Plugins menu. From the Plugins menu, select Manage and Install Plugins. The Plugins dialog opens.

    Enter GML Application Schema in the search bar. Select the plugin and click on Install Plugin in the bottom right corner. The QGIS GML Application Schema Toolbox plugin will install.

    To access the plugin, click on the Plugins menu in QGIS. A QGIS GML Application Schema Toolbox plugin menu option is added to the Plugins menu dropdown.

    Using the GML Application Schema Toolbox plugin

    In order to view your hale»connect WFS in QGIS, you will need a URL link to your download service. You can directly access the URL from the Download Services section of your dataset. To copy the URL to the clipboard, click the icon to the right of the URL.

    Open QGIS and click on the Plugins menu. From the Plugins menu, select QGIS GML Application Schema Toolbox. Next, select Load (wizard).

    In the Load wizard, select WFS and click Next.

    In the WFS Options menu of the Load wizard, click the New button. This opens a dialog which allows you to define a new WFS connection. Give your new connection a name, and enter the URL to your hale»connect service in the URL field. Click OK.

    Your new layer should appear at the top of the WFS Options menu. Click the Connect button to access the service. You can select one or more feature types to add to your map. You can limit the number of features requested by checking the Limit to parameter. When you are finished, click the Next button. Select Load in XML mode and click the Next button.

    In the XML options menu, click Swap X/Y axis. The default coordinate reference system of hale»connect services is EPSG:4326. hale»connect uses the EPSG database definition of EPSG code 4326 (WGS 84) and QGIS uses the Proj4 definition of EPSG code 4326 (WGS 84) and this causes the axis to be flipped. You can change the applied CRS in the Source section of the layer properties after you load the WFS. Click the Finish button in the bottom right corner of the Load wizard dialog to add the data to your map.

    The layers you select should appear in the layers panel on the left. Right click on a layer and select Properties to view more information about the service.

    Identifying features in a WFS

    Once you have added your download service layers to the map, you can explore them using the Identify button.

    Click on the Identify button. In a standard QGIS installation, the button is found in the top row of toolbars. It is marked with an info symbol and white arrow. First, click on the Identify icon. Next, click on the layer you want to explore in the Layer panel on the left. Next, click on a feature in the map. The Identify Results panel will appear to the right, click on the View feature form icon to view the attributes of the feature you are interested in.

    A new dialog opens in QGIS which enables you to navigate through any level of nested, complex GML to further investigate the linked resources, linked features, codelists or attributes that you are interested in.

    Learn more

    QGIS maintains its own documentation. For more information about using OGC services in QGIS, visit the following link: Working with OGC Data


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    Enhance discovery and retrieval of geospatial data using SOA and Semantic Web technologies

    The ability to find and access geospatial data over the Internet through a single tool will be a great benefit for researchers who try to collect relevant data for a particular study. This requires a unified system to bring together diverse data sources so that they can be searched simultaneously in a single environment. Dealing with diversity of data sources and coping with heterogeneities that exist between them are the major challenges in this endeavor. This paper presents the efforts of combining Open Geospatial Consortium (OGC) specifications, Universal Description, Discovery and Integration (UDDI) standards and ontologies to address these challenges. The primary goal is to enhance discovery of web services compliant with OGC specifications and promote access to geospatial information via the OGC services. To this end, this paper introduces an approach for incorporating ontology into UDDI registry and proposes an advertisement algorithm for representing service metadata contained in the OGC capabilities document via UDDI data structures, providing therefore a way to record semantic, descriptive and technical information of OGC services inside UDDI registry. Then the paper illustrates how this information could be used to enhance service discovery with the aid of semantic reasoning. Based on the proposed approaches and service-oriented architectures (SOA) strategies, a web-based prototype system has been developed in order to help users query, access and visualize geospatial data of different types in a unified interface. Several running examples are given to demonstrate the feasibility and effectiveness of the prototype.

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    ► We propose a solution for enhancing discovery of geospatial services conforming to OGC specifications. ► The solution relies on a combination of UDDI, OGC standards and Semantic Web technology. ► We develop a Web-based prototype system by leveraging SOA principle and RIAs technologies. ► The prototype system enables to discover and access geospatial service and data in a single system. ► The system is demonstrated through running examples for resolving real world problems.


    Overview of WMTS Operations¶

    WMTS specifies several operation types, two of which are required in a compliant WMTS implementation, and another which is optional.

    The GetCapabilities response is characterized in a “ServiceMetadata” document, which describes how to identify WMTS resources or generate WMTS request operations. The primary content of the metadata is TileMatrixSet summary information and detailed content such as bounding box, supported coordinate reference system (CRS), whether a well-known scale set is available, and TileMatrix data about any of a number of levels. An optional “Themes” section, when present, obviates the need to specify any inheritance rules for layer properties. Under a resource-oriented architectural style, an appropriate resource name such as “WMTSCapabilities.xml” would be chosen.

    The GetTile operation under a procedural-oriented architectural style allows WMTS clients to take the information from the GetCapabilities response to request a particular Tile of a particular TileMatrixSet in a predefined format. Under the resource-oriented style, the client merely requests the representation of any offered Tile resource by performing a request to the address following the standard semantics of the transport protocol.

    GetFeatureInfo requests may be made about the features at or near a particular pixel location. Requests must specify the tile along with a pixel location on that tile, and the WMTS server may choose which information to provide about nearby features. WMTS Clause 7.3.1 recommends Level 0 of the Geography Markup Language (GML) Simple Features Profile as the supported document format for FeatureInfo resources.


    MapProxy Authorization API¶

    MapProxy looks in the request environment for a mapproxy.authorize entry. This entry should contain a callable (function or method). If it does not find any callable, then MapProxy assumes that authorization is not enabled and that all requests are allowed.

    The signature of the authorization function:

    service – service that should be authorized

    layers – list of layer names that should be authorized

    environ – the request environ

    dictionary with authorization information

    The arguments might get extended in future versions of MapProxy. Therefore you should collect further arguments in a catch-all keyword argument (i.e. **kw ).

    The actual name of the callable is insignificant, only the environment key mapproxy.authorize is important.

    The service parameter is a string and the content depends on the service that calls the authorize function. Generally, it is the lower-case name of the service (e.g. tms for TMS service), but it can be different to further control the service (e.g. wms.map ).

    The function should return a dictionary with the authorization information. The expected content of that dictionary can vary with each service. Only the authorized key is consistent with all services.

    The authorized entry can have four values.

    The request for the given service and layers is fully authorized. MapProxy handles the request as if there is no authorization.

    Only parts of the request are allowed. The dictionary should contains more information on what parts of the request are allowed and what parts are denied. Depending on the service, MapProxy can then filter the request based on that information, e.g. return WMS Capabilities with permitted layers only.

    The request is denied and MapProxy returns an HTTP 403 (Forbidden) response.

    The request(er) was not authenticated and MapProxy returns an HTTP 401 response. Your middleware can capture this and ask the requester for authentication. repoze.who ’s PluggableAuthenticationMiddleware will do this for example.

    New in version 1.1.0: The environment parameter and support for authorized: unauthenticated results.

    Limited_to ¶

    You can restrict the geographical area for each request. MapProxy will clip each request to the provided geometry – areas outside of the permitted area become transparent.

    Depending on the service, MapProxy supports this clipping for the whole request or for each layer. You need to provide a dictionary with bbox or geometry and the srs of the geometry. The following geometry values are supported:

    Bounding box as a list of minx, miny, maxx, maxy.

    String with one or more polygons and multipolygons as WKT. Multiple WKTs must be delimited by a new line character. Return this type if you are getting the geometries from a spatial database.

    Shapely geometry object. Return this type if you already processing the geometries in your Python code with Shapely.

    Here is an example callback result for a WMS GetMap request with all three geometry types. See below for examples for other services:

    Performance¶

    The clipping is quite fast, but if you notice that the overhead is to large, you should reduce the complexity of the geometries returned by your authorization callback. You can improve the performance by returning the geometry in the projection from query_extent , by limiting it to the query_extent and by simplifing the geometry. Refer to the ST_Transform , ST_Intersection and ST_SimplifyPreserveTopology functions when you query the geometries from PostGIS.


    GetFeatureInfo in WMS using a box? - Geographic Information Systems

    Sentinel-2 WMS/WMTS/WFS/WCS services support many custom parameters which affect the generation of the service responses. In the following table, all the available custom parameters, such as preview modes, are listed. All these parameters are optional.

    For the examples on how to use them, see this documentation.

    Note that atmospheric correction is not a parameter anymore, as we now only support L2A atmospheric correction. Read more about it here.

    The maximum allowable cloud coverage in percent. Cloud coverage is a product average and not viewport accurate hence images may have more cloud cover than specified here.

    The priority by which to select and sort the overlapping valid tiles from which the output result is made. For example, using mostRecent will place newer tiles over older ones therefore showing the latest image possible. Using leastCC will place the least cloudy tiles available on top.

    This parameter allows for a custom evaluation script or formula specifying how the output image will be generated from the input bands. See Custom evaluation script usage for details.

    EVALSCRIPT parameter has to be BASE64 encoded before it is passed to the service.

    This parameter allows for a custom evaluation script or formula to be passed as an URL parameter, where the script itself is located (it should be on HTTPS).

    Outputs imagery only within the given geometry and cropped to the geometry's minimum bounding box.

    Used only when requesting JPEGs.

    Sets the image upsampling method. Used when the requested resolution is higher than the source resolution.

    Sets the image downsampling method. Used when the requested resolution is lower than the source resolution.

    Enables or disables the display of in-image warnings, like "No data available for the specified area".


    Watch the video: Getting Start Geoserver (October 2021).