Blog GIS & Territories

This is the continuation of the following articles,  The Geoserver Explorer plugin for QGis (1):
installation and configuration , and The Geoserver Explorer plugin for QGis (2): limitations
, here we will discuss the detailed user instructions for the plugin.

GeoServer Explorer: Available commands and actions

Contextual menu actions

Below you will find information about the available commands based on
the type of element you click in GeoServer Explorer, as well as an explanation for
their use. GeoServer catalog element.

• Clean (remove unused items). Cleans all the catalogue’s styles that are not used
  by any layer, and all storage data that is not published across a layer.
• Remove. Deletes the catalogue from the connected list. It is, also, removed from the list that is kept
  between sessions, so it will not appear again the next time QGIS is started and
  the GeoServer Explorer is executed.

Publish layers to this catalogue : Displays the Publish Layer dialog box

Check the box for each layer you want to publish among those currently
in your QGIS project. Then select the workspace in which each layer is to be
imported and the layer name in the GeoServer catalog. By default, the name of
the layer in the QGIs project is used, but this name may not be a valid XML
name, in which case it will appear in red and you will need to enter a valid
name. Publish project to this catalogue. Publishes all layers of the project. The publishing operation is configured through the
following dialog box:

All the layers will be published in the selected workspace.

If there are groups in the QGIS project, they will also be created. Groups
are not replaced when a project is published. If a group with the same name
exists in the catalogue, a warning message will be displayed and the group will
not be downloaded.

If you want to create a group containing all published layers, enter its
name in the Name text box of the global group. Otherwise, leave
it blank and the global group will not be created.

Workspaces item

• New workspace…. Adds a new workspace.
• Clean (remove unused warehouses). Removes all data stored that are not published by
  any layer in the catalogue.

Layers element

• Add layer to QGIS project. Similarly to the Add to QGIS project command for feature or cover types, but it also uses style information in the
  case of vector layers. The style is uploaded as an SLD
  file and configured for the corresponding QGIS layer. In the case of raster layers, SLD styles are not
  supported and for this reason the layer will use a default style.
• Delete .Delete the catalogue layer. The associated style will be removed if it is not
  used by any other layer and if the corresponding configuration parameter is
  set. Another configuration parameter
  can be set to, automatically, delete the underlying data stored when a layer is
  deleted. If a GWC layer associated with
  this layer exists, it will also be deleted.

Add style to layer. Adds
a new style to the layer in the list of available layers in the catalogue. The style is selected in the dialog box below:

This is another and easier way to export the QGis style to SLD and then upload the SLD to
GeoServer

  Element style New style from QGIS layer. Creates a new style in the GeoServer catalogue using
the style of a QGIS layer. The QGIS layer to use and the name of the style
to be created in the GeoServer catalogue are specified in the following dialog
box:

• Clean (remove unused styles). Removes all styles that are not used by any layer.
• Consolidate styles Searches for layers in the catalogue whose styles
  match the same symbology. This can occur when downloading
  layers with the same style, since each downloaded layer will have its own layer
  with the same name as the layer, and all will share the same SLD code. This command looks for styles that represent the
  same symbology and, in the layers that use them, replaces the corresponding
  styles with the first style in the list of redundant styles. Once the command is executed, only one style of
  those that are identical will be used, while the others will not be used by any
  layer. These unused styles are not
  deleted, but the Clean command (remove unused styles) will be removed from the catalogue.

Style element.

• Edit…. Opens the QGIS symbology editor
  to change the style of the layer. Create your symbology and accept the dialog box to be closed. This will cause the style update. Note that the QGIS interface for defining a
  symbology is used to edit a GeoServer style, but since the layer that uses the
  style is not available, some restrictions exist:
  • If the
    style element is in a layer element, the explorer will get the attribute names
    of the layer, so you can use them to define your symbology rules. However, the min and max values ​​of these
    attributes in the layer are not available. You will not be able to use them to define ranges or categories.
  • If the
    style element is not in the layer element, the explorer will try to find out if
    the style is used by any other layer, and will use that layer in case it can
    find it. If multiple layers use a style,
    the first one will be used. If no
    layer is found (no layer uses this style), the style will be open for editing,
    but no field name will be available. You will change the style as if it matched a QGIS layer without
    attributes.
  • The labelling
    is not supported in this case when extracting the SLD style to edit. This means that you can add a label to the style
    you set and that it will be correctly downloaded into the catalogue, but if the
    style you are editing has a certain type of labelling, it will not appear in
    the style editor. QGIS, which will always have disabled tagging.
  • Editing a
    style using the QGIS symbology editor is only supported for vector styles. If you try to edit a raster style in this way, Explorer will display a warning message that
    these styles cannot be edited.

Edit SLD… By clicking on it, you can directly edit the contents
of the corresponding SLD, using a dialog box with an XML editor, such as the
one shown below:

By clicking OK the corresponding SLD body in the catalogue will be
updated, with the current text of the editor. No validation is performed on the
client side, but if the publisher’s content is not a valid SLD, GeoServer will
refuse to update it. The corresponding error message returned by GeoServer will
be displayed in the QGIS message bar.

If the style is in a layer element, the following additional options are
available:

• Set as default style. Sets the style as the default style for the layer.
• Add style to layer… A style can be selected in the
  dialog box that will be displayed, and it will be added as an additional style
  for the layer.
• Remove style from layer. Removes a style from the list of layer replacement
  styles. Not enabled for the default style
  of the layer.

items setting

When you click it, the configurable parameters in the description panel
will be shown. You can edit them and press the Save button to download the
changes to the corresponding catalogue and update it.

GeoWebCache layers element

New GWC layer… Adds a new GWC layer from an
existing layer to the GeoServer catalogue. The
properties of the cache layer are defined in a dialog box like the one shown
below:

GeoWebCache layer element

• Delete. Deletes the cache layer
• Edit. Modifies the properties of the GWC layer by opening
  the same dialog box used to define them when creating the layer.

Seed … Starts
a building operation for the cache layer. The
operation is defined via the following dialog:

The zone to be generated must be entered in the field located in the
lower part of the dialog box, with a string of 4 values ​​separated by commas
(xmin, xmax, ymin, ymax). If no value is entered, the total extent of the layer
to be generated is used.

Another way to define the region to be generated is to click the Set
button on the canvas on the right side of the dialog box. This
will cause the dialog box to disappear temporarily and display the QGIS map. Just
click and drag to set the desired generation region, and the dialog box will
appear again, containing the coordinates of the area.

• Empty. Deletes all cache data for a given layer.

When a generation operation is started, the description box
corresponding to the GWC layer being generated will show the current state of
the operation.

Since these operations can be very long, depending on the zoom levels
selected and the area covered by the layer, the progress is not displayed using
a progress bar.

Instead, you can use QGIS as usual while the operation is running in the
background, and to update the status just click the update link in the
description box to get the current number of tiles processed. If you want to
stop the building operation, just click the kill link .

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Atilio Francois