Ferramentas gerais¶

Renderização Dependente da Escala¶

Scale-dependent rendering allows you to specify the minimum and maximum scales at which a layer will be visible. To set scale-dependent rendering, open the Properties dialog by double-clicking on the layer in the legend. On the General tab, click on the Scale dependent visibility checkbox to activate the feature, then set the minimum and maximum scale values.

Pode determinar os valores da escala em primeiro lugar aumentando a um nível que quer usar e não ter valores de escala na barra de estado do QGIS.

Controlando a Renderização do Mapa¶

A renderização do mapa pode ser controlada de várias maneiras, como é descrito em baixo.

Medir comprimentos, áreas e ângulos¶

^{Measure Line}: QGIS is able to measure real distances between given points according to a defined ellipsoid. To configure this, choose menu option Settings ‣ Options, click on the Map tools tab and select the appropriate ellipsoid. There, you can also define a rubberband color and your preferred measurement units (meters or feet) and angle units (degrees, radians and gon). The tool then allows you to click points on the map. Each segment length, as well as the total, shows up in the measure window. To stop measuring, click your right mouse button.

Figure Measure 1:

Measure Distance (Gnome)

^{Measure Area}: Areas can also be measured. In the measure window, the accumulated area size appears. In addition, the measuring tool will snap to the currently selected layer, provided that layer has its snapping tolerance set (see section Configurando a Tolerância de Atracção e Raio de Pesquisa). So, if you want to measure exactly along a line feature, or around a polygon feature, first set its snapping tolerance, then select the layer. Now, when using the measuring tools, each mouse click (within the tolerance setting) will snap to that layer.

Figure Measure 2:

Measure Area (Gnome)

^{Measure Angle}: You can also measure angles. The cursor becomes cross-shaped. Click to draw the first segment of the angle you wish to measure, then move the cursor to draw the desired angle. The measure is displayed in a pop-up dialog.

Figure Measure 3:

Measure Angle (Gnome)

Selecionar e desselecionar elementos¶

A caixa de ferramentas QGIS fornece várias ferramentas para seleccionar elementos no enquadramento do mapa. Para seleccionar um ou mais elementos, simplesmente clique em e seleccione a sua ferramenta:

• ^{Seleccionar Elemento Único}

• ^{Seleccionar Elementos por Rectângulo}

• ^{Seleccionar Elementos por Polígono}

• ^{Seleccionar Elementos por Delimitação Livre}

• ^{Seleccionar Elementos pelo Raio}

To deselect all selected features click on ^{Deselect features from all layers}.

Grelha¶

^Grid allows you to add a coordinate grid and coordinate annotations to the map canvas.

Figure Decorations 1:

Janela da Grelha

1. Seleccione a partir do menu Ver ‣ Decorações ‣ Grelha. A janela de diálogo inicia. (veja figure_decorations_1).

2. Activate the Enable grid checkbox and set grid definitions according to the layers loaded in the map canvas.
3. Activate the Draw annotations checkbox and set annotation definitions according to the layers loaded in the map canvas.

4. Clique [Aplicar] para verificar se tudo está como o esperado.

5. Clique [OK] para fechar a janela de diálogo.

Etiqueta de Direitos de autor¶

^{Copyright label} adds a copyright label using the text you prefer to the map.

Figure Decorations 2:

The Copyright Dialog

1. Seleccione a partir do menu Ver ‣ Decorações ‣ Etiqueta Copyright. O diálogo iniciará (veja figure_decorations_2).

2. Enter the text you want to place on the map. You can use HTML as shown in the example.
3. Choose the placement of the label from the Placement combo box.
4. Make sure the Enable Copyright Label checkbox is checked.

5. Clique [OK].

In the example above, which is the default, QGIS places a copyright symbol followed by the date in the lower right-hand corner of the map canvas.

Seta do Norte¶

^{North Arrow} places a simple north arrow on the map canvas. At present, there is only one style available. You can adjust the angle of the arrow or let QGIS set the direction automatically. If you choose to let QGIS determine the direction, it makes its best guess as to how the arrow should be oriented. For placement of the arrow, you have four options, corresponding to the four corners of the map canvas.

Figure Decorations 3:

Diálogo da Seta do Norte

Barra de Escala¶

^{Scale Bar} adds a simple scale bar to the map canvas. You can control the style and placement, as well as the labeling of the bar.

Figure Decorations 4:

Diálogo da Barra de Escala

QGIS only supports displaying the scale in the same units as your map frame. So if the units of your layers are in meters, you can’t create a scale bar in feet. Likewise, if you are using decimal degrees, you can’t create a scale bar to display distance in meters.

Para adicionar a barra de escala:

1. Select from menu View ‣ Decorations ‣ Scale Bar. The dialog starts (see figure_decorations_4).
2. Choose the placement from the Placement combo box.
3. Choose the style from the Scale bar style combo box.
4. Select the color for the bar Color of bar or use the default black color.
5. Set the size of the bar and its label Size of bar .
6. Make sure the Enable scale bar checkbox is checked.
7. Optionally, check Automatically snap to round number on resize.

8. Clique [OK].

Anotações Html¶

The ^{Html Annotation} tools in the attribute toolbar provides the possibility to place the content of an html file in a balloon on the QGIS map canvas. Using the Html Annotation tool, click into the map canvas and add the path to the html file into the dialog.

Anotações SVG¶

The ^{SVG Annotation} tool in the attribute toolbar provides the possibility to place an SVG symbol in a balloon on the QGIS map canvas. Using the SVG Annotation tool, click into the map canvas and add the path to the SVG file into the dialog.

Formulários de anotações¶

Additionally, you can also create your own annotation forms. The ^{Form Annotation} tool is useful to display attributes of a vector layer in a customized Qt Designer form (see figure_custom_annotation). This is similar to the designer forms for the Identify features tool, but displayed in an annotation item. Also see this video https://www.youtube.com/watch?v=0pDBuSbQ02o from Tim Sutton for more information.

Figure annotation 2:

Formulário de anotação personalizado no Qt Designer

Criando um Marcador¶

Para criar um marcador:

1. Aproximar ou mover para uma área de interesse.

2. Seleccione a opção do menu Ver ‣ Novo Marcador ou carregue Ctrl-B.

3. Introduza um nome descritivo para o marcador (até 255 caracteres).

4. Pressione Enter para adicionar o marcador ou [Apagar] para remover o marcador.

Repare que tem múltiplos marcadores com o mesmo nome.

Trabalhando com Marcadores¶

To use or manage bookmarks, select the menu option View ‣ Show Bookmarks. The Geospatial Bookmarks dialog allows you to zoom to or delete a bookmark. You cannot edit the bookmark name or coordinates.

Aproximando a um Marcador¶

From the Geospatial Bookmarks dialog, select the desired bookmark by clicking on it, then click [Zoom To]. You can also zoom to a bookmark by double-clicking on it.

Apagando um Marcador¶

To delete a bookmark from the Geospatial Bookmarks dialog, click on it, then click [Delete]. Confirm your choice by clicking [Yes], or cancel the delete by clicking [No].

Embebendo camadas¶

A seguinte janela permite que possa embeber camadas de outros projectos. Aqui está um pequeno exemplo:

1. Pressione para ver outro projeto a partir do conjunto de dados Alaska.

2. Select the project file grassland. You can see the content of the project (see figure_embed_dialog).
3. Press Ctrl and click on the layers grassland and regions. Press [OK]. The selected layers are embedded in the map legend and the map view now.

Figure Nesting 1:

Selecione as camadas e grupos para incorporar

While the embedded layers are editable, you can’t change their properties like style and labeling.

Removendo camadas embebidas¶

Right-click on the embedded layer and choose ^Remove.