Layers

Table of contents

1. Creating Layers
2. Importing layers
3. Publishing layers
4. Configuring Layers
5. Layer Permissions
6. Sharing Layers
7. JMap extensions
8. Bulk editing a layer set

---

A project is composed of an ordered list of layers. Layers are used to display data extracted from spatial data sources. Each layer is related to a specific spatial data source. Vector layers are related to vector data sources and display vector data while raster layers are related to raster data sources. The layer configuration determines the appearance of the data (style of the layer), the visibility thresholds, what information is associated with the spatial data (attributes), etc. Each layer has its own configuration parameters for labelling, reports, thematics, etc.

Layers are created in the project they belong to. Specific permissions can be configured for each layer. Thus, some layers can be accessed only by a subset of users authorized to open the project.

The layers of a project can be organized into a logical tree-like structure or hierarchy. This feature is useful to better organize information when working with projects that have a high number of layers. In client applications, users are able to control the visibility of the layers belonging to the same group in one click. Refer to the section titled Organizing Layers for more information on this subject.

Layers can be copied from one project to another or even shared between various projects located on the same JMap Server or on separate JMap Servers. Refer to the section titled Sharing Layers for more information on this topic.

The layers of a project are displayed in the Layers section, which may be accessed from the JMap Admin project configuration interface. In the List tab, the table shows basic information about each layer of the project. When you click on the name of a layer, a details section displays. The Hierarchy tab displays the groups and subgroups with the layers that compose them. The tasks you can perform from this tab are detailed in the Organizing Layers section.

In the List tab of the Layers section of a project, you can perform the tasks described in the table. For some tasks, you must select more than one layer.

This button allows you to access the Permissions section, where you can configure the permissions of the selected layers. See Layer Permissions for more details.

Creating Layers

Each layer of a project in JMap takes its data from a spatial data source. Thus, before layers can be created, the related data sources must already exist (see Creating Spatial Data Sources for more information).

Creating a new layer

To create a new layer, press Create in the Add menu of the Layers section of a project. Note that the new layer will have the same name as the data source by default. The name can be changed later.

The next steps are different for vector layers and raster layers. Note that creating a raster layer is also different for each type of raster data source. Jump to the corresponding section below.

Creating a vector layer

The request mode determines how the vector data is managed by JMap Server. It can greatly influence the system’s overall performance.

Advanced parameters

Most of the time, the following advanced parameters don’t need to be modified.

Creating a raster layer based on a WMS data source

To create a raster layer based on a WMS spatial data source, you need to tell JMap what data to request from the WMS server. The WMS server publishes a list of all the layers it can serve and their properties. In JMap, the WMS layer creation interface allows you to select the layers to include in the WMS layer you wish to create.

Creating a raster layer based on a GDAL or ECW/ECWP data source

Creating a raster layer from a WMTS data source

Importing layers

You can add a layer to a project by importing it from a project that has been exported from another JMap server. The Exporting and Importing section provides details on exporting and importing a JMap server’s resources. To import a layer in a project, you must also create a data source in JMap Server containing the data of the imported layer.

When you select Add / Import… the Importation wizard will guide you through the process to import one or more layers from the project where they are found.

1. To start the process, select the Importation file. Click on Browse to access the File browser.

2. Select the .properties file that contains the project whose layers you wish to import.

3. Click on Next.

4. Select the Project that contains the layer you wish to import.

5. Select the Layers to import.

6. Click on Next.

7. If the project in which you are importing the layer contains a layer with the same name as the one you are importing, select an option to resolve the conflict between these layers: Create a new layer with a different name, Replace the existing layer or Use existing layer.

8. Click on Next.

9. If the JMap Server in which you are importing the layer contains a spatial data source with the same name as the data source of the layer you are importing, select an option to resolve the conflict between these data sources: Create a new data source with a different name, Replace the existing data source or Use existing data source.

10. Click on Next.

11. A summary lists the number of imported resources for the project: layers, databases, remote connections, spatial data sources, style templates, and metadata templates.

12. Press Import. The layer is added to the project and a new spatial data source is created in JMap Server.

Publishing layers

A layer must be published to be accessible to the users. A layer that is not published is not part of the project, and in no way can users see it or access it.

When a new layer is created, it is not published by default. This allows you to do further configuration tasks on the layer before making it available for the users. For example, it is important to configure visibility thresholds appropriately according to the scale before the layer can be seen by users.

After layer creation, you must press the Publish button in the layer’s detail section.

Unpublishing an existing layer can be useful to make it unavailable to the users without actually deleting it.

Configuring Layers

The layer configuration interface allows you to access layer information as well as parameter configuration functions such as style, labels, or reports.

The raster layer configuration interface contains the General information, Layer parameters, and Visibility thresholds sections.

Attributes

The Attribute configuration window contains three tabs: Metadata, Statistics, and Attribute sample.

The Statistics tab provides simple statistics about the attribute. The Attribute sample tab displays the value of the attribute for a sample of layer elements.

Layer Permissions

There are several different types of permissions for a project’s layers. The following tables describe each one of these.

Administrator permissions

User permissions

To modify layer permissions, press in order to select the users and groups to which you wish to grant permissions. Only the users and groups who are already authorized to open the project containing the layer can be granted permissions associated with this layer.

Sharing Layers

JMap allows you to share layers between projects that are on the same server or that originate from remote servers that are connected. Layer sharing allows you to manage data more effectively (avoids duplication, saves time) by reusing existing layers instead of creating new layers in each project. When the original layers are modified, the changes can automatically be viewed in all projects that have referenced layers pointing towards these shared layers. Referenced layers cannot be modified directly, save a few basic settings. Only the original shared layer can be modified.

The figure presents the layer sharing between projects on the same server and on different servers. The properties of the Rivers layer cannot be modified in projects 1 and 3. The original layer is in project 2.

Sharing layers between projects on the same JMap Server

To share layers between projects on the same JMap Server, no action is required. Layers can be accessed freely from any project on the same server. Refer to Accessing shared layers for more information.

Sharing layers between different JMap Servers

If you wish to share a project’s layers in order to access them from another JMap Server, you must assign a special remote access permission to a user for these layers. In order to do this, access the project layers section for which you wish to share these layers.

1. Select one or more layers.

2. Click on Permissions.

3. In the permission management interface, select the user account or group to which you wish to assign the remote access permission (you can add user accounts and groups by clicking on ).

4. Select the Remote access permission. The account used must match the user account through which the connection to this JMap Server was established. If you are using a group, the aforementioned user account must be included within it.

Once the layers have been shared, they can be selected from the remote JMap Server and inserted in this server’s projects. Refer to Accessing shared layers for more information.

To stop layers from being shared, simply remove the Remote access permission from these layers.

Accessing shared layers

To access existing layers from different projects located on the same JMap Server or shared layers on other JMap Servers, you must click on Add and select Clone / Reference in the layers section of the project to which you would like to add these layers.

In the Clone / Reference layers section:

1. Select a JMap Server from which you wish to clone or reference layers. If you choose Local server, you can select the projects and layers of the local server without these being shared. The other servers in the list are the JMap Servers for which a JMap Server to JMap Server connection exists. Refer to the JMap Server to JMap Server Connections section for more information on creating JMap Server to JMap Server connections.

2. Select the project from which you wish to clone or reference layers. Once the project has been selected, the list of available layers displays.

3. Select the layers you wish to clone or reference and move them to the list on the right.

4. Select the Clone or Reference option.

   If you choose the Clone option, the selected layers will be duplicated towards your project. They will be exact copies of the original layers, but there will be no connection between the copies and the original layers. You can modify the copies without affecting the originals. If you delete a cloned layer, this doesn’t affect the original layer. If you delete the original layer, this doesn’t affect its cloned layers. However, duplicated layers always use the same spatial data source as the original layer. If this data source is modified or deleted, this will affect the duplicated layers.

   If you select the Reference option, the original layers will be accessed by reference. This means that a direct connection will be maintained between the layers of your project and the original layers. You will not be able to modify these layers in your project. If the original layers are modified, the changes will appear wherever references to these layers exist, after a short delay. If you delete a referenced layer, the original layer will not be affected. If you delete the original layer, the referenced layers will no longer work and will have to be deleted manually.

JMap extensions

Some JMap extensions require the configuration of specific parameters at the layer level. To access the extension configuration interface, press and then the name of the extension. Once the settings are configured, press Save.

Bulk editing a layer set

You can edit different settings for a set of layers. You must select the layers to modify in the List tab of the Layers section of the project. Afterwards, press the Update button, and click on the Bulk edit… option. The Bulk edit interface will open.

---