This page provide some additional information about the main features of the interface, as well as some practical examples of its application. It's also mentioned the technological basis on which this solution is based.
SELECTION OF THEMES>
This application allows the user to choose the themes to represent on the interface, from a set of themes stored in the database.
These themes are organized based on the thematic structure considered on the INSPIRE Directive and are selected from a specific form (Figure 1).
Figure 1 - Part of the form that allows you to select which themes will be represented on the graphical interface.
If the interface also provides modeling data results (results obtained from the Modeling System), this information can also be consulted on the generated map by simply selecting the desired water line(s) and simulation time on the form (Figure 2) .
Figure 2 - Section of the form that lets you select the simulation results.
Once chosen which themes will be represented on the graphical interface, the user should press the "Display map" button (located at the bottom of the window) to begin the transfer of the data.
Next to this button you can find a list of pre-defined themes sets that can be customized by the user, removing or adding other themes.
Figure 3 - Section of the form that allows you to choose which pre-defined sets to use.
Once invoked the "Display map" button a new window appears with a graphical interface on which are represented the selected themes.
The information of each map request to the server is transferred to the client machine at once. All subsequent operations are dependent on the processing capabilities of the client machine.
THE MAIN WINDOW OF THE GRAPHICAL INTERFACE>
The web map service is made available through the graphical application GeoClient. In the following figure we can identify their main characteristics.
Figure 4 - General appearance of the Geoclient - the graphical interface of Web-SIG.
1 - Legend: list of themes with the possibility of activation, configuration and occultation.
2 - Legend: buttons to go down/ascend the legend (useful for maps with several themes/classes).
3 - Mini-map: allows you to locate the represented area on the map.
4 - Map: representation of a "Polygon" theme.
5 - Map: representation of a "Point" theme".
6 - Map: representation of a "Line" theme.
7 - Toolbar: Additional information about the selected object.
8 - Toolbar: navigation, information and configuration buttons.
The toolbar located on top of the interface allows quick access to the key features of the GeoClient application.
The toolbar consists on 5 groups of icons: Navigation, Information, Labels, KML and Preferences.
Figure 5 - Geoclient toolbar.
1 - Zoom in: allows you to increase the scale of the map.
2 - Original zoom: lets show the map in its initial scale.
3 - Zoom out: allows you to decrease the scale of the map.
4 - Info: enables the visualization of information associated with graphic objects (once active, simply click with the mouse over a graphic element on the map to obtain its information table).
5 - Query: lets you search for information based on objects attributes.
6 - Labels: set the properties of the labels (font size and the field to display).
7 - Labels: lets you show/hide labels (automatically).
8 - Labels: assign labels manually.
9 - Export the active themes to KML (GoogleEarth).
10 - Preferences of the interface: to configure the graphical interface preferences.
11 - Additional information about the interface.
The toolbar also displays information that allows the user to confer the coordinates of a given point on the map through the mouse pointer (the M and P coordinates are shown on the right side of the bar).
In addition is also displayed the class and name of the selected object (theme group + name of the object).
Figure 6 - Display of the name and location of a particular object on the map.
THE GRAPHICAL INTERFACE>
This interface provides many functionalities, among which are::
- Presentation of themes of different types (point, line or polygon);
- Possibility of navigation on the map (change scale and translations);
- Query information associated with graphical entities;
- Manual or automatic placement of labels on graphical entities;
- Presentation of a configurable legend;
- View information organized by classes;
- Query results on graphical or tabular format;
- Possibility to export themes to GoogleEarth (KML extension);
- Includes a location map (mini-map);
- Multiple options viewing.
The interface consists on interactive maps that allow you to explore information regarding various themes, by exploring the territory and doing queries. At the top of the window
is located a toolbar that allows you to show more or less detail, identify structures visibles on the map, put labels on graphical entities, export themes to KML, etc.
On the right side of the window is located the mini-map (useful for situating the visible area of the map) and the legend which lists the themes that are part of the map. The list of themes allows the
user to define which themes should be visible, as well as allowing other types of configurations, such as the color to use for each theme or if you prefer, the color values for classes.
The navigation on the map involves the application of changes of scale and translations. The scale change can be performed through the following ways:
- Using the toolbar buttons (first group, referring to zoom options);
- Using the "Zoom in" and "Zoom out" options of the pop-up menu, accessible through the right button of the mouse;
- Using shortcut keys of the SVG plug-in, described in Table 1.
In the case of translations, they may be carried through the following options:
- Moving the rectangle on the mini-map that represents the visible area;
- Using shortcut keys of the SVG plug-in, described in Table 1.
In the map area you can increase the viewing scale through two ways: hold down CTRL key and
click with the left mouse button on the spot where you want to enlarge the map; hold down the CTRL key and click
and drag with the left mouse button, selecting a region to which you want to apply the zoom.
In the map area you can decrease the viewing scale by keeping the CTRL and SHIFT keys and clicking with
the left mouse button.
In the map area you can perform translations holding the ALT key, and at the same time click and drag the viewable area
with the left mouse button.
Table 1 - Description of shortcut keys used for navigation on the GeoClient map.
As mentioned above, when moving the mouse cursor over an object it's shown on the toolbar the name of that object and the class to which it belongs (see Figure 6).
However, at a certain point you may wish to know more information about that object.
Each theme is associated with an attribute table. The attribute table contains a record for each geographical entity, is this entity represented by a point, a line or a polygon.
The Info button (see Figure 5) allows you to view the attributes of a particular object, selecting the point, polygon or line upon which we intend to obtain information.
The information are displayed in the table and can still be obtained a chart for all numeric fields.
Figure 7 - Graphical information on GeoClient interface.
When you want to obtain information about an entity represented on the map you must do the following:
- Activate the theme group of this object (if the theme isn't active in "Legend");
- Activate the "Info" button on the toolbar;
- Click with the left mouse button on the desired object (point, polygon, line).
The search tool allows you to quickly find structures or other objects, of which we know the name or partial name, using uppercase and lowercase letters without distinction.
It also allows searching for numerical data that meet certain criteria. The selection of items that result from query allows access to the respective data or its quick location on the map.
Another interesting feature is the exportation of themes to KML format (recognized by the GoogleEarth).
So any active theme in GeoClient interface can be exported and displayed on GoogleEarth, allowing to combine this information with others from different sources.
Simply activate the desired theme(s) and use the "Export to Google Earth" button or use the "Export active themes to KML" option, accessible through the SVG plug-in popup menu.
Figure 8 - Visualization of exported themes on Google Earth.
Observation: this feature requires that you have the Google Earth installed on your machine to view the result shown as ilustrated on the picture above. Otherwise, you only be able to see the content of generated KML file.
On the left side of the interface we find the Legend. The legend of the map allows not only to identify the themes as well as change the color of them.
This configuration can be further customized by the user through a classification according the values of the numeric fields or representing the values graphically (through bars or circles).
Figure 9 - Visualization of the "Sub-basin" theme with graduated color.
Figure 10 - Representation of the "Sub-basin" theme with pie charts and bars (area).
These options are available through the "Legend Properties" window, in which are chosen the types of legend, the fields to classify and the number of classes.
To access the "Legend Properties" just click with the mouse button on the theme name you want to change (in the "Legend" panel).
To each graphical entity is assigned a corresponding field of its database table whose value is used to set the object's label.
This feature can be used for all entities at once or placed entity by entity.
There are three buttons on the toolbar that let you perform the management of the labels (see Figure 5).
The user can choose to show all the labels automatically or manually assign the tags to the desired objects.
Figure 11 - Displaying labels on the GeoClient interface.
This web interface is based on a Web Server (eg, Apache), a Database Server (eg, MySQL), the PHP programming language and on SVG.
On the "client machine" side, the following requirements are recommended:
- Browser: Internet Explorer 6 or above (compatibility with other web browsers is currently not guaranteed).
- Browser configuration: plug-in Adobe SVG Viewer installed.
This interface is based on information previously collected, treated and stored on the database. The information update should be performed with appropriate database management tools.
The following image presents some simulations results of the Modeling System, on the GeoClient interface. Clicking on a particular segment of the water line, the user has access to a table with simulation data (hydrodynamic and water quality values).
Figure 12 - Example of simulation results on the GeoClient interface of Web-SIG application.
The following image illustrates the query feature. This feature allows the identification of the results in table or graph format, being the search criteria established based on a wide set of comparison operators.
Figure 13 - Example of a query result on the GeoClient interface of Web-SIG application.
The following image illustrates the possibility to visualize orthophotomaps on the interface, facilitating the geographic location of the elements on the map.
Figure 14 - Visualization of orthophotomaps on the GeoClient interface of Web-SIG application.
As a last example we have a view relating to the visualization of climate variables, in which the theme "Temperature" is displayed in graduated colors, defined by the user.
Figure 15 - Presentation of climatic variables data (temperature), represented by graduated colors.
WORKING GROUP RESPONSIBLE FOR THE IMPLEMENTATION OF INTERFACE>
Prof. Doutor José Manuel Pereira Vieira
Prof. Doutor José Luís da Silva Pinho
Eng. José Araújo
Eng. Rui Pinho
Eng. Rui Teixeira
Dra. Andrea Ribeiro