QGIS: project settings

This section describes how to optimize your QGIS projects to publish as a WebGis service.

Thanks to the integration with QGIS Server, all the symbology aspects associated with the singoly layers are automatically reproduced on the WebGis service

In the QGIS cartographic projects you can set some parameters and options that affect functionalities and contents in the derivative WebGis service, such as:

  • the webgis service identification name

  • the associated basic metadata

  • the capabilities of the service

  • the possibility to exclude some associated print layouts on the WebGis service

  • which layers are queryable and searchable

  • which layers to expose with the different OGC services (WMTS, WFS, WCS)

  • which fields (for each vector data) are exposed as WMS and/or WFS

  • the Themes (Views) defined at the project level

  • layer/group management from embedded projects

  • the structure of the query form visible on the WebGis service

  • the editing widget, constraints and default values (also based on QGIS expressions) for every fields of vector layers

  • the associated print layouts, report included

The following paragraphs describe which QGIS project settings are more relevant in relation to the published WebGis service.

Project property

From the Project Properties menu, you can access the Project Properties window and the three submenus of our interest:

  • General

  • Data sources

  • QGIS server

General

General Settings

In this section it is possible to define the title of the project, consequently the title of the WebGis service.

This title will be used at the G3W-SUITE application level to uniquely identify the published project; for this reason it will not be possible to assign the same name to different projects published on the WebGis service.

We advise against using special characters, or numbers in the project name.

_images/projecttitle.png

Data sources

The option Automatically create transaction group where possible is automatically inherited in the online editing function.

Layers Capabilities

This submenu defines the querable and/or searchable layers at the WebGis service level.

  • Check the Identifiable column if you want that the layer will be searchable on the WMS service

  • Check the Searchable column if you want that the layer will be querable on the WMS service

NB: this differentiation is only possible by using the QGIS APIs such as Search URL endpoint. See dedicated paragraph

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QGIS Server

Service capabilities

In this section it is possible to define the capabilities of the service.

This information, together with info about the structure of the attribute tables of the layers present in the project, will be displayed in the Metadata session of the cartographic client.

See also dedicated paragraph

_images/qgisservercapabilities.png

Capabilities WMS - Advertised extent

In this section it is possible to define the geographical extension displayed when the WebGis service starts.

To define it, set the desired geographical view on the map and then click on the ‘Use Current Canvas Extent’ button.

_images/qgisserversetmapexpetent.png

WMS Capabilities - CSR restrictions

In this section it is possible to define the projection systems for which the project is available in relation to OGC services.

It is clearly necessary to insert the projection system on which the project was made, this SR is added by clicking on the ‘Used’ button.

Other geographic reference systems can be implemented by clicking on the ‘+’ button and choosing from the list of reference systems.

_images/qgisserversrisrestriction.png

Capabilities WMS - Exclude layouts

In this section it is possible to exclude some of the print layouts that are associated with the cartographic project from the availability of the WebGis service.

_images/qgisserverexludecompositions.png

Capabilities WMS - General aspects

Two further aspects are manageable with regard to WMS capabilities

  • in general it is recommended to check use the layer ids as names option

  • the option Add geometry to feature response must be checked to activate the zoom to the features on the WebGis service

_images/qgisservergeneralaspects.png

WMTS Capabilities

In this section it is possible to define which layers are exposed as WMTS services defining the various options

WFS Capabilities

In this section it is possible to define which layers are exposed as WFS services.

The WFS service is needed if you want activate following types of query:

  • Query by bbox

  • Query by polygon (rectangle/square)

  • Query by draw polygon

It is sufficient to check only the Published column

_images/qgisservergeneralaspectswfs.png

WCS Capabilities

In this section it is possible to define which rasters are exposed as WCS services

General aspects

Themes (Views)

The creation of Themes (combination of off / on layers and differentiated symbology styles) is managed at the WebGis service level.

A specific menu on the webgis will allow you to choose the Theme to be displayed.

The views will be parameterizable at the URL level of the related webgis service.

Layer order

The option to define the layer order different from the order in the TOC on the QGIS project is automatically supported.

Legend

The activation of the Filter legend by Map content option on the QGIS project is automatically applied to the derived WebGis service.

If the Show features count function is activated in the QGIS project at vector layer level, the same information will be displayed on the web map.

The number of features updates automatically based on the style associated with the layer.

Spatial Bookmarks

In case Spatial Bookmarks are saved at the QGIS project level, they will also be available on the web map.

Mutually exclusive groups

The activation on the QGIS project of the Mutually exclusive group option for the layers groups is automatically applied to the derived WebGis service.

1:N and N:M relations

The interface inherits the 1: and N:M relations defined in the Project Properties from the QGIS project.

The suite also manages relations based on multiple keys.

ATTENTION: to correctly manage these types of relations it is NECESSARY to insert the reference to the relations in the customized form

_images/qgislayerproperties_displayform_relations.png

Embedded project

It is possible to publish QGIS projects that contain layers or groups of layers deriving from embedded projects. It is clearly necessary to publish the embedded project first and then those derived from it. An update of the embedded project will result in a consequent modification of all derived projects. The request to delete the basic embedded project causes a warning message as this operation will cause problems on all derived projects.

Layers properties

Simbology

The rendering style associated with the individual layers is replicated autonomously on the WebGis service.

The suite allows the switching on/off of the individual categories linked to the various simbolgy methods (categorized, graduated, by rules …).

_images/g3wsuite_simbology_onoff.png

If external SVG icons are used (added to the basic ones of QGIS, via the Settings -> Options -> System -> SVG paths), these must be uploaded to the server (through the File Manager tool) in order to be used by QGIS Server.

Manage custom SVG icons

In the installation procedure of the G3W-SUITE application, an svg named directory is created on the server.

Within this directory it is therefore possible to store SVG icons, also organized in subdirecory.

The Configurations icon _images/iconconfiguration.png, located in the upper right corner of the Administration Panel, allows you to access a menu that includes the File Manager item.

_images/g3wclient_icon_config.png

_images/g3wsuite_administration_configuration_menu.png

Through this tool it is possible to manage SVG icons on the server in a simple and intuitive way.

_images/g3wsuite_administration_file_manager.png

The SVG folder on the server must reflect the structure in any subfolders present locally.

NB: The name of this directory is defined by the basic settings set during the installation of the suite. See dedicated paragraph.

PS: remember that the File Manager tool also allows you to manage the synchronization of geographical data (in the case of using physical files) and the management of multimedia files.

See also dedicated paragraph

Multi-style layer

The suite manages the presence of multiple styles associated with a layer.

It will be possible to dynamically choose the style on the cartographic client.

It will be possible to manage the styles associated with a layer from the Administration component, also by loading .qml file styles and setting the default style among those present.

Definition of the fields that can be consulted for each layer

Within the QGIS project it is also possible to define, for each layer, which fields are available following query on the WebGis service.

To define these settings, you access the properties of one of the vectors previously defined as searchable and choose the Source Fields submenu in the Layer Properties window.

This submenu lists the fields associated to the table of the vector.

The check box relating to the WMS column defines whether the values contained in this field will be available following the query on the WebGis service.

_images/qgislayerproperties_wmsfields.png

Definition of the attribute display form

For each layer it is possible to define the structure of the attributes form associated with displaying the results following query operations.

On QGIS, we can build a personalized form (query form) by creating thematic tabs and groups and defining the distribution of the individual fields and their aliases.

This structural organization will be replicated directly on the query form on the WebGis service.

The current version of QGIS also handles conditional forms and cascade drill-downs

Layer basic information

If you set a descriptive information in the Abstract form of the QGIS Server session of the Layer Properties, this information will be associated with the layer at the webgis level.

Temporal settings

This functionality is only available using QGIS Server >= 3.26

The Temporal Controller functions in QGIS are replicated on the webgis component

Time series functionality works on both vector and raster data, even in multi-layer mode.

Time setting on vector data is limited to the Single Field with Date/Time case

_images/qgislayerproperties_displayform_relations.png

Viewing multimedia content

Multimedia contents (images, pdf, web URL …) can be viewed interactively on the map client following publication of the QGIS project.

In the case of web links, simply insert them (preceded by the prefix http:// or https://) within the dedicated attribute fields

In the case of multimedia files it is necessary:

  • upload the media file to the media_user folder (folder exposed on the web) accessible through the File Manager tool in the Suite Administration Panel

  • insert the web link to this file in the dedicated attribute field

The link to the file can be obtained in the following way:

  • application domain + media_user + path of the file + file name

Example:

  • application domain: https://dev.g3wsuite.it

  • file file_A.pdf located in the folder /media_user/form/

  • web link: https://dev.g3wsuite.it/media_user/form/file_A.pdf

Following queries at the cartographic client level, we will have different behaviors based on the type of content:

  • image: preview display in the form, click on the preview to display the image in real size

  • web link or other multimedia file: display of an Open orange button to allow consultation of the content

_images/qgis_form_attribute.png

_images/qgislayerproperties_displayform.png

Performances optimization

Mandatory rules

  • PostGreSQL/PostGis, SQLite/Spatialite and GeoPKG layers must have a primary key

  • the primary key field and all fields involved in search, join, 1:n or N:M relations or editing function have to be published as WMS

  • don’t use commas for aliases associated with layers

  • style settings defined at the auxiliary data level are not supported

Tips

  • when using rule-based/categorized classification create indexes on the column(s) involved in the rule expression

  • start the project with only a few layers turned on by default

  • do not exceed three nesting levels in the groups of layers defined in the TOC