GI-go Geobrowser quick user guide

Introduction

Although the main use of GI-go is as a powerful Java client of GI-cat, nevertheless GI-go represents a stand-alone multi-platform discovery solution developed by ESSI-Lab.

Its query engine is based on the GI-cat business logic, it allows discovering and access of geospatial resources across distributed and heterogeneous data sources, including OGC CSW, WMS, WCS. Our Java Web Start-powered and friendly tool, provides an uniform interface and harmonizes in a transparent way the heterogeneous resources to a profile of ISO 19115. An heterogeneous set of geospatial data sources is indeed supported, the complete list available in the GI-cat documentation

GI-go helps the user in discovering and browsing the available datasets, retrieving and evaluating their description and performing distributed queries according to any combination of the following criteria: geographic area, temporal interval, topic of interest and data source (i.e. where, when, what, who).

Connecting GI-go client to GI-cat

After a sample installation, GI-cat exposes a standard CSW 2.0.2 ISO Application Profile interface, as well as an extended, GI-cat SOAP interface. By default, it federates a sample configuration, including WMS and WCS services from geospatial agencies all over the world. This section describes how to test GI-cat is by connecting with our GI-go GeoBrowser.

Open GI-go and configure a new source; then just input the following parameters, depending on the interface you want to exercise.

Accessing GI-cat through the GI-cat 6.0 SOAP extended interface

Alias

a descriptive name for the service (e.g. My GI-cat).

Access type

the service type, in this case GI-CAT

Version

the service version, in this case 6.0

Endpoint

the GI-cat endpoint, it is the URL of the GI-cat Welcome page

Protocol Binding

choose SOAP-DOC

Free Comment

add optionally a comment about the service

Accessing GI-cat through the CSW 2.0.2 ISO AP interface

Alias

a descriptive name for the service (e.g. My GI-cat).

Access type

the service type, in this case CSW/ISO

Version

the service version, in this case 2.0.2

Endpoint

you can find this endpoint from the GI-cat Welcome page

Protocol Binding

choose HTTP-GET

Free Comment

add optionally a comment about the service

Accessing GI-cat through the CSW 2.0.2 Core AP interface

Alias

a descriptive name for the service (e.g. My GI-cat).

Access type

the service type, in this case select CSW/CORE

Version

the service version, input 2.0.2

Endpoint

you can find this endpoint from the GI-cat Welcome page

Protocol Binding

choose HTTP-GET

Free Comment

add optionally a comment about the service

You should now be able to browse the content of GI-cat in the "Resources Tab", or issue a query against it. Results are obtained from the servers included in the current active configuration.

Launching Instructions

Please refer to GI-go homepage to download and try GI-go.

Preparing a query

GI-go provides an uniform GUI for querying the underneath GI-cat logic.

In order to specify a query criterion, you must activate the correpondent tab (i.e. Area, Resources, Time and Text search) checking the correspondent check (just above the tab labels).

Once a tab is activated, you must select a correct search criterion (i.e select an area in the Area tab, or input some text in the Text search field). As depicted in Figure 1, a red icon on a tab indicates that the selection is not correct (i.e no area is selected in the Area tab, or no text is written in the Text search field) and the "Submit button" is disabled; a blue icon indicates the correctness of the relative search criterion.

When a tab is deactivated, the query will be performed without the correspondent search criterion, and if all the tabs are deactivated, the query will be performed withouth any constraint (ALL is asked).

Figure 2 (above), shows a screenshot of the Area tab. To make a selection, the button with the crosshair icon must be pressed. It is possible to select an area, to move it inside the map, and to resize it using the anchor points on the selection edges.
It is also possible to enter the area values using the text fields on the left side of the tab for a more accurated selection.
The map can be dragged to shows areas outside the tab view, and zoom capability is also available.

Figure 3 shows how to browse services to evaluate federated geo-information resources. Note that:

1. Resources can be: services, datasets or collection of datasets, and each resource is described by a set of metadata which are visualized in a tree-like component in the right side of the Resource tab.
2. Metadata are structured according to ISO 19115 data model, and model mapping is performed when necessary (e.g. THREDDS to ISO 19115 metadata mapping).

Figure 4 shows the Time selection tab; on the left side, you can select the start time, and on the right side, the end time. Of course if the end time precedes the start time or viceversa, the submit button will be disabled.

The text tab permits to add a text constraint to the query. Just enter the desired string in the text field, and the constraint will be mapped on a match search on resource properties title, subject and abstract. You can also explore and select a taxonomy concept from the taxonomy tree. The data is retrieved on-line from the GBIF collection. The selected taxon criterion will be added as a query keyword.

Retrieving query results

The latest GI-go version is able to perform mediated access of multiple matching resources after a query. See the GI-go mediated access guide for more information on this topic.

The section below describes the classic single resource access.

For each submitted query, a new window like the one depicted in Figure 6, will be opened.

• In the left side of the window the resulting datasets are shown. Click on a dataset, to see its content structured according to ISO 19115 data model ( see the table with columns Name/Value on the right side of Figure 6).
  
• Moreover, after clicked on a dataset, the correspondent preview download will begin; when the preview is ready, it will be showed in the pane just underneath the dataset content table. Preview is avaliable for pictorial formats such as PNG or JPG, and for XML documents. A dataset with the italic style, indicates that relative preview is currently downloading; if the dataset is underlined (like that one in the figure above), than its preview is ready. Finally, a strikedthrough dataset , indicates that the relative format is not visualizable as preview.

To download resources, just check their checkboxes and click the download button, than follow the download wizard. As you can read in the Figure 7, it is also possible to download a text file wich contains the resource URL for each available format. With the window in Figure 8, it is possible to select the folder, the name and the format of the resources.

We briefly describe now some of the more interesting features exposed by GI-cat^? and used by GI-go :

• incremental query : this feature allows to retrieve the resulting query items in an incremental manner; in other words, we are able to access and visualize the intermediates query results
  
• query feedbacks : this feature makes possible to check the query status relative to a certain service, both with a process percentage, and with some descriptive messages (see Figure 9)
  
• query interruption : with this feature, it is possible to interrupt the query process relative to a selected service (e.g a WMS). This may be helpful, for example, if a service, during query processing, delays too much.

Managing profiles

A profile, is a collection of services on which distribute the query . As default, there is only the "on line profile", a profile stored in our server, and usable as template for other custom profiles.

• Profiles can be added, removed, imported and exported. Once selected a profile (like "default profile" in Figure 10) click the "Apply selected profile" button, to load and to use the correspondent resources in the query engine.
• Resources, can be added, removed or edited. To edit a resource, select it in the "Profile resources" pane, than use the "Resource properties pane" on the right side of the window.
• To add a resource, click the "Add button" and correctly fill the form that will be visualizated. Once you have edited one or more profile resources, save the configuration pressing the "Save button".

Metadata profiler

It is possible to personalize the displayed set of metadata which characterize each listed or returned resource. Each metadata element can be personalized as for: visibility, label, graphic style (e.g. label, color, icon, etc.).

-- Last Updated ( Wednesday, 01 October 2008 )