Catalog. Searching for geodata
Introduction
The catalogue service allows you to search for geographic information on the Internet. gvSIG offers a user-friendly interface which allows you to find geodata and load it in the view, as long as the nature of the data allows this.
Connecting to a server
Before you can carry out a search, you will need to connect to a catalogue server. To access the wizard, you will first need to open a view and then click on the following button:
The first window of the catalogue opens. Input the required parameters to connect to a server. These include:
- The server address.
- The server protocol, which in the case of the catalogue can be:
- Z39.50: General information retrieval protocol.
- SRU/SRW: Variant of Z39.50.
- CSW: Catalogue protocol defined by the OGC in the “Catalogue Interface 2.0” specification.
- Data base name: You only need to indicate the data base you wish to connect to in the case of z39.50. If no value is input you will connect to the default data base.
Then click on the “Connect” button. If the connection is made and the server supports the specified protocol, a new window will appear to start the search.
Searching
To carry out a search, you need to fill in the fields that appear in the following form.
Click on the button and the window will drop down to show more fields which will allow you to carry out an advanced search. The fields you can search in are set by the server. This means that some of the search fields in this form may have no effect in some servers.
If you change the view zoom, the new coordinates will be reflected in this form. If you wish to restrict the search area enable the corresponding check box. Then click on “Search” and wait for the search to be carried out.
Viewing the results
If the search has been successful, a new window containing the search results will open.
Use the “Previous” and “Next” buttons to see each of the results obtained.
The left-hand side of the window shows information about the metadata obtained. If you wish to see all the information, click on the "Description" button.
You will also be able to see a miniature image at all times, metadata permitting.
If the metadata has any geodata associated to it, the “Add layer” button will be enabled.
gvSIG can currently recognise different types of associated resources, such as WMS, WCS, Postgis tables and web pages.
If you click on this button, a new window will be opened and will show all the resources the application has been able to find.
If you click on a WMS, WCS or Postgis type resource, the new layer will automatically be loaded in gvSIG. If the resource is a web page, for example, the operating system’s default browser.
