Módulo eVis¶

Iniciar o módulo de Pesquisa de Eventos¶

To launch the Event Browser module, click on Database ‣ eVis ‣ eVis Event Browser. This will open the Generic Event Browser window.

The Event Browser window has three tabs displayed at the top of the window. The Display tab is used to view the photograph and its associated attribute data. The Options tab provides a number of settings that can be adjusted to control the behavior of the eVis plugin. Lastly, the Configure External Applications tab is used to maintain a table of file extensions and their associated application to allow eVis to display documents other than images.

Percebendo a janela de Exibição¶

To see the Display window, click on the Display tab in the Event Browser window. The Display window is used to view geocoded photographs and their associated attribute data.

Figure eVis 1:

A janela de exibição eVis

1. **Janela de exibição*: A janela onde a fotografia irá aparecer.

2. Botão Aproximar: Aproxima para ver com mais detalhe. Se a imagem inteira não for possível de exibir na janela de exibição, uma barra de deslocamento aparecerá no lado esquerdo e no fundo da janela para que possa mover à volta da imagem.

3. Botão Afastar: Afastar para visualizar mais área.

4. Zoom to full extent button: Displays the full extent of the photograph.
5. Attribute information window: All of the attribute information for the point associated with the photograph being viewed is displayed here. If the file type being referenced in the displayed record is not an image but is of a file type defined in the Configure External Applications tab, then when you double-click on the value of the field containing the path to the file, the application to open the file will be launched to view or hear the contents of the file. If the file extension is recognized, the attribute data will be displayed in green.

6. Botões de Navegação: Use o botão Anterior e Seguinte para carregar o elemento anterior e seguinte quando mais que um elemento é seleccionado.

Entendendo a janela de Opções¶

Figure eVis 2:

A janela de Opções eVis

1. File path: A drop-down list to specify the attribute field that contains the directory path or URL for the photographs or other documents being displayed. If the location is a relative path, then the checkbox must be clicked. The base path for a relative path can be entered in the Base Path text box below. Information about the different options for specifying the file location are noted in the section Especificando a localização e nome da fotografia below.
2. Compass bearing: A drop-down list to specify the attribute field that contains the compass bearing associated with the photograph being displayed. If compass bearing information is available, it is necessary to click the checkbox below the drop-down menu title.
3. Compass offset: Compass offsets can be used to compensate for declination (to adjust bearings collected using magnetic bearings to true north bearings). Click the Manual radio button to enter the offset in the text box or click the From Attribute radio button to select the attribute field containing the offsets. For both of these options, east declinations should be entered using positive values, and west declinations should use negative values.

4. Directório do caminho base: O caminho base para o caminho relativo definido na Figure_eVis_2 (A) será anexado.

5. Replace path: If this checkbox is checked, only the file name from A will be appended to the base path.
6. Apply rule to all documents: If checked, the same path rules that are defined for photographs will be used for non-image documents such as movies, text documents, and sound files. If not checked, the path rules will only apply to photographs, and other documents will ignore the base path parameter.
7. Remember settings: If the checkbox is checked, the values for the associated parameters will be saved for the next session when the window is closed or when the [Save] button below is pressed.

8. Restaurar valores: Restaurar os valores nesta linha para a configuração padrão.

9. Restore defaults: This will reset all of the fields to their default settings. It has the same effect as clicking all of the [Reset] buttons.

10. Guardar: Isto guardará as configurações sem fechar o painel das Opções.

Entendendo a janela de Configuração de Aplicações Externas¶

Figure eVis 3:

A janela de aplicações Externas eVis

1. File reference table: A table containing file types that can be opened using eVis. Each file type needs a file extension and the path to an application that can open that type of file. This provides the capability of opening a broad range of files such as movies, sound recordings, and text documents instead of only images.

2. Adicionar novo tipo de ficheiro: Adicionar um novo tipo de ficheiro com uma extensão única e o caminho para a aplicação que pode abrir o ficheiro.

3. Apagar a linha actual: Apagar o tipo de ficheiro destacado na tabela e definido por uma extensão de ficheiro e o caminho para aplicação associada.

Iniciar o módulo de Eventos ID¶

To launch the ‘Event ID’ module, either click on the ^{Event ID} icon or click on Database ‣ eVis ‣ Event ID Tool. This will cause the cursor to change to an arrow with an ‘i’ on top of it signifying that the ID tool is active.

To view the photographs linked to vector features in the active vector layer displayed in the QGIS map window, move the Event ID cursor over the feature and then click the mouse. After clicking on the feature, the Event Browser window is opened and the photographs on or near the clicked locality are available for display in the browser. If more than one photograph is available, you can cycle through the different features using the [Previous] and [Next] buttons. The other controls are described in the ref:evis_browser section of this guide.

Iniciar o módulo da Ligação à Base de Dados¶

To launch the ‘Database Connection’ module, either click on the appropriate icon ^{eVis Database Connection} or click on Database ‣ eVis ‣ Database Connection. This will launch the Database Connection window. The window has three tabs: Predefined Queries, Database Connection, and SQL Query. The Output Console window at the bottom of the window displays the status of actions initiated by the different sections of this module.

Ligar à base de dados¶

Click on the Database Connection tab to open the database connection interface. Next, use the Database Type combo box to select the type of database that you want to connect to. If a password or username is required, that information can be entered in the Username and Password textboxes.

Enter the database host in the Database Host textbox. This option is not available if you selected ‘MS Access’ as the database type. If the database resides on your desktop, you should enter “localhost”.

Enter the name of the database in the Database Name textbox. If you selected ‘ODBC’ as the database type, you need to enter the data source name.

When all of the parameters are filled in, click on the [Connect] button. If the connection is successful, a message will be written in the Output Console window stating that the connection was established. If a connection was not established, you will need to check that the correct parameters were entered above.

Figure eVis 4:

A janela de ligação da Base de Dados eVis

1. Database Type: A drop-down list to specify the type of database that will be used.

2. Servidor da Base de Dados: O nome do servidor da base de dados.

3. Port: The port number if a MySQL or PostgreSQL database type is selected.
4. Database Name: The name of the database.
5. Connect: A button to connect to the database using the parameters defined above.
6. Output Console: The console window where messages related to processing are displayed.

7. Utilizador: Utilizador para usar quando a base de dados é protegida por uma palavra-passe.

8. Palavra-passe: Palavra-passe para usar quando a base de dados é protegida por uma palavra-passe.

9. Consultas Pré-Definidas: Separador para abrir a janela “Consultas Pré-definidas”.

10. Ligação da Base de Dados: Separador para abrir a janela “Ligação à Base de Dados”.

11. Consulta SQL: Separador para abrir a janela da “Consulta SQL”.

12. Help: Displays the online help.

13. OK: Fecha a janela principal da “Ligação à Base de Dados”.

Correndo consultas SQL¶

SQL queries are used to extract information from a database or ODBC resource. In eVis, the output from these queries is a vector layer added to the QGIS map window. Click on the SQL Query tab to display the SQL query interface. SQL commands can be entered in this text window. A helpful tutorial on SQL commands is available at http://www.w3schools.com/sql. For example, to extract all of the data from a worksheet in an Excel file, select * from [sheet1$] where sheet1 is the name of the worksheet.

Click on the [Run Query] button to execute the command. If the query is successful, a Database File Selection window will be displayed. If the query is not successful, an error message will appear in the Output Console window.

In the Database File Selection window, enter the name of the layer that will be created from the results of the query in the Name of New Layer textbox.

Figure eVis 5:

O separador de Consulta SQL eVis

1. Janela de texto da Consulta SQL: Um ecrã para introduzir as consultas SQL.

2. Correr Consulta: Botão para executar a consulta introduzida na Janela de Consulta SQL.

3. Janela da Consola: A janela da consola onde as mensagens relacionadas com o processamento são exibidas.

4. Help: Displays the online help.

5. OK: Fecha a janela principal Ligação à base de daos.

Use the X Coordinate and Y Coordinate combo boxes to select the fields from the database that stores the X (or longitude) and Y (or latitude) coordinates. Clicking on the [OK] button causes the vector layer created from the SQL query to be displayed in the QGIS map window.

To save this vector file for future use, you can use the QGIS ‘Save as...’ command that is accessed by right-clicking on the layer name in the QGIS map legend and then selecting ‘Save as...’

Correndo consultas pré-definidas¶

With predefined queries, you can select previously written queries stored in XML format in a file. This is particularly helpful if you are not familiar with SQL commands. Click on the Predefined Queries tab to display the predefined query interface.

To load a set of predefined queries, click on the ^{Open File} icon. This opens the Open File window, which is used to locate the file containing the SQL queries. When the queries are loaded, their titles as defined in the XML file will appear in the drop-down menu located just below the ^{Open File} icon. The full description of the query is displayed in the text window under the drop-down menu.

Select the query you want to run from the drop-down menu and then click on the SQL Query tab to see that the query has been loaded into the query window. If it is the first time you are running a predefined query or are switching databases, you need to be sure to connect to the database.

Click on the [Run Query] button in the SQL Query tab to execute the command. If the query is successful, a Database File Selection window will be displayed. If the query is not successful, an error message will appear in the Output Console window.

Figure eVis 6:

The eVis Predefined Queries tab

1. Open File: Launches the “Open File” file browser to search for the XML file holding the predefined queries.
2. Predefined Queries: A drop-down list with all of the queries defined by the predefined queries XML file.
3. Query description: A short description of the query. This description is from the predefined queries XML file.

4. Janela da Consola: A janela da consola onde as mensagens relacionadas com o processamento são exibidas.

5. Help: Displays the online help.

6. OK: Fecha a janela principal da “Ligação à Base de Dados”.

XML format for eVis predefined queries¶

The XML tags read by eVis

A complete sample XML file with three queries is displayed below:

<?xml version="1.0"?>
<doc>
 <query>
   <shortdescription>Import all photograph points</shortdescription>
   <description>This command will import all of the data in the SQLite database to QGIS
      </description>
   <databasetype>SQLITE</databasetype>
   <databasehost />
   <databaseport />
   <databasename>C:\textbackslash Workshop/textbackslash
eVis\_Data\textbackslash PhotoPoints.db</databasename>
   <databaseusername />
   <databasepassword />
   <sqlstatement>SELECT Attributes.*, Points.x, Points.y FROM Attributes LEFT JOIN
      Points ON Points.rec_id=Attributes.point_ID</sqlstatement>
   <autoconnect>false</autoconnect>
 </query>
  <query>
   <shortdescription>Import photograph points "looking across Valley"</shortdescription>
   <description>This command will import only points that have photographs "looking across
      a valley" to QGIS</description>
   <databasetype>SQLITE</databasetype>
   <databasehost />
   <databaseport />
   <databasename>C:\Workshop\eVis_Data\PhotoPoints.db</databasename>
   <databaseusername />
   <databasepassword />
   <sqlstatement>SELECT Attributes.*, Points.x, Points.y FROM Attributes LEFT JOIN
      Points ON Points.rec_id=Attributes.point_ID where COMMENTS='Looking across
      valley'</sqlstatement>
   <autoconnect>false</autoconnect>
 </query>
 <query>
   <shortdescription>Import photograph points that mention "limestone"</shortdescription>
   <description>This command will import only points that have photographs that mention
      "limestone" to QGIS</description>
   <databasetype>SQLITE</databasetype>
   <databasehost />
   <databaseport />
   <databasename>C:\Workshop\eVis_Data\PhotoPoints.db</databasename>
   <databaseusername />
   <databasepassword />
   <sqlstatement>SELECT Attributes.*, Points.x, Points.y FROM Attributes LEFT JOIN
      Points ON Points.rec_id=Attributes.point_ID where COMMENTS like '%limestone%'
      </sqlstatement>
   <autoconnect>false</autoconnect>
 </query>
</doc>