From Existing Table

Owned by Robert Sikorski
Last updated: 23 Sept 2021 by Wojciech Mozolewski
5 min read

Once the import script has been run on the server we are ready to create references in Earthlight. To create new reference for a layer please follow the steps below:

  1. Click here to select the repository.
  2. You can use this search box to quickly locate desired table.
  3. Highlight layer/s for which you want to create references.
  4. Select destination folder for references.
  5. Click Create layer reference to start the operation.

You can also reference spatial views and non-spatial tables which store Easting and Northing data.

Creating reference to Views and Non-spatial tables works in similar way as common table, however it required entering some additional information.


From Earthlight version 2014 R2 it’s possible to order tables by creation date (timestamp). However, only new layers imported by Earthlight or by one of Earthlight tools will contain creation date.

Views

  1. Choose views group from the Repository drop down menu.
  2. Choose a view that you want to reference.
  3. Select your reference location.
  4. Click Create layer reference button.

Now you need to set your reference settings.

  1. First, choose a primary key column for your view.
  2. Set view’s geometry column.
  3. Specify geometry type.
  4. Add all the tables that are referenced to your view. You can use search box to quickly locate desired table.

Please note

Selecting tables which are referenced to your view is required for creating database triggers on them and to allow Earthlight refreshing caches of the view. It is required for example when one of the view 'source' tables changes.

If you are not aware which tables are used in the view:

  • please ask your db administrator about this information,

or

  • select a table which is not a part of the view, but you know that it is regularly updated (every day for instance). In this case, referenced view caches will be updated so often as the selected table.


Non-Spatial Tables

In case of Non-spatial tables – select Primary key(1), Easting(2) & Northing(3) columns and set SRID(4).

Web Mapping Service


The WMS is consumed by the application server and not client (user) machine. In other words, in order for the WMS to work, it is necessary that the domain used by the WMS is accessible from the application server.

Here’s the example of usage for some free geology data from http://ogc.bgs.ac.uk/

In order to add a new reference to the WMS layer go to Administration > Create > From Existing Table.

Now you should choose the directory where a reference will be created(1) (this is mandatory to enable the Create web layer reference button). Next click the arrow on the Create web layer reference button and choose Create WMS reference(2) option from the drop-down list.

To reference the layer, you have to set all the WMS settings inside the displayed dialog.

  1. First you have to fill the Address field for the Web Map Service (we used http://ogc.bgs.ac.uk/cgi-bin/BGS_Bedrock_and_Superficial_Geology/wms).
  2. Choose the version of WMS server (most servers serve all the versions of WMS, so if you are not sure which one is good, you can try v1.3.0).
  3. Click the Get capabilities button to get the layer names from the server.
  4. Choose the layer, you want to reference.
  5. Write layer name. It has to be at least 3 characters long and consist exclusively of letters, numbers, underscores, spaces and dashes.
  6. Set SRS (Spatial Reference System) to EPSG:27700.
  7. Choose the tile images format and click OK.

Now the layer is referenced and ready for use. You can add it to the map.


Web Map Tile Service

It is required for Earthlight user to have access to the Internet to be able to connect to a remote WMTS server.

To reference the layer, you have to set all the WMTS settings inside the displayed dialog.

  1. First you have to fill the Address field for the Web Map Tile Service (we used http://a.tile.openstreetmap.org/{TileMatrix}/{TileCol}/{TileRow}.png).
  2. Click the Get capabilities button to get the layer names from the server.
  3. Choose the layer, you want to reference.
  4. Write layer name. It has to be at least 3 characters long and consist exclusively of letters, numbers, underscores, spaces and dashes.
  5. Set SRS (Spatial Reference System) to desired EPSG.
  6. If you would like to limit maximum available zoom level for referenced layer, you can change this setting. 
  7. Choose the tile images format and click OK.

Now the layer is referenced and ready for use. You can add it to the map.


Web Feature Service


You can also add a WFS layer reference in the selected directory by choosing the Create WFS layer reference from the dropdown menu. As is the case with all previously described service references, the application environment needs to be exposed to the service domain for the reference to be created.



Selecting this option will display the Reference WFS window consisting of 6 elements:



1. Address - here you can provide the service URL and use the Fetch button to send the GetCapabilities request and acquire the service content.

2. Version - here you can set the service version

3. Layers - the service content will be displayed here after using the Fetch button from section 1. You can select multiple tables to be downloaded from the service as well as define the tables and layer references names.

4. Refresh job - in this dropdown, you can select the previously configured Scheduler job which will periodically refresh the WFS table.

5. Overwrite tables - check this option if you would like to overwrite the preexisting tables in your database.

6. This section displays the directory in your repository where the WFS layer reference will be created.


After filling in all the necessary information simply click Reference and the WFS layer will be created in your repository along with the database table.