% vim:autoindent:set textwidth=78:

\section{Features at a Glance}\label{feature_glance}

% when the revision of a section has been finalized, 
% comment out the following line:
%\updatedisclaimer

After a first and simple sample session in Section \ref{label_getstarted} we now 
want to give you a more detailed overview of the features of QGIS. 
Most features presented in the following chapters will be explained and described in 
own sections later in the manual.

\subsection{Starting and Stopping QGIS}\label{label_startinqgis}

In Section \ref{samplesession} you already learned how to start QGIS. We will 
repeat this here and you will see that QGIS also provides further command line options. 

\begin{itemize}
\item \nix{Assuming that QGIS is installed in the PATH, you can start QGIS 
by typing: \usertext{qgis}  at a command prompt or by double clicking on the QGIS
application link (or shortcut) on the desktop or in the application menu.} 
\item \win{Start QGIS using the Start menu or desktop shortcut, 
or double click on a QGIS project file.}
\item \osx{Double click the icon in your Applications folder. If you need to start QGIS 
in a shell, run /path-to-installation-executable/Contents/MacOS/Qgis.}
\end{itemize} 

To stop QGIS, click the menu options \{\nix{}\win{File} \osx{QGIS}\} > Quit,
or use the shortcut \keystroke{Ctrl+Q}.

\subsubsection{Command Line Options}\index{command line options}
\label{label_commandline}

\nix QGIS supports a number of options when started from the command line. To
get a list of the options, enter \usertext{qgis ---help} on the command line.
The usage statement for QGIS is:

\small
\begin{verbatim}
qgis --help
Quantum GIS - 1.3.0-Mimas 'Mimas' (exported)
Quantum GIS (QGIS) is a viewer for spatial data sets, including
raster and vector data.
Usage: qgis [options] [FILES]
  options:
        [--snapshot filename]           emit snapshot of loaded datasets to given file
        [--width width]                 width of snapshot to emit
        [--height height]               height of snapshot to emit
        [--lang language]               use language for interface text
        [--project projectfile]         load the given QGIS project
        [--extent xmin,ymin,xmax,ymax]  set initial map extent
        [--nologo]                      hide splash screen
        [--help]                        this text

  FILES:
    Files specified on the command line can include rasters,
    vectors, and QGIS project files (.qgs):
     1. Rasters - Supported formats include GeoTiff, DEM
        and others supported by GDAL
     2. Vectors - Supported formats include ESRI Shapefiles
        and others supported by OGR and PostgreSQL layers using
        the PostGIS extension
\end{verbatim}
\normalsize

\begin{Tip} \caption{\textsc{Example Using command line arguments}}
\qgistip{You can start QGIS by specifying one or more data files
on the command line. For example, assuming you are in the 
qgis\_sample\_data directory, you could start QGIS with a vector layer 
and a raster file set to load on startup using the following command: 
\usertext{qgis ./raster/landcover.img ./gml/lakes.gml}
}
\end{Tip}

\minisec{Command line option \usertext{---snapshot}}
This option allows you to create a snapshot in PNG format from the current view.
This comes in handy when you have a lot of projects and want to 
generate snapshots from your data.

Currently it generates a PNG-file with 800x600 pixels. This can be adapted
using the \usertext{---width} and \usertext{---height} command line
arguments. A filename can be added after \usertext{---snapshot}.

\minisec{Command line option \usertext{---lang}}
Based on your locale QGIS, selects the correct localization. If you would like 
to change your language, you can specify a language code. For example: 
\usertext{---lang=it}
starts QGIS in italian localization. A list of currently supported
languages with language code is provided at
\url{http://wiki.qgis.org/qgiswiki/TranslatorsCorner} 

\minisec{Command line option \usertext{---project}}
Starting QGIS with an existing project file is also possible. Just
add the command line option \usertext{---project} followed by your project
name and QGIS will open with all layers loaded described in the given file.

\minisec{Command line option \usertext{---extent}}
To start with a specific map extent use this option. You need to add the bounding box of your extent in the following order separated by a comma:
\begin{verbatim}
--extent xmin,ymin,xmax,ymax
\end{verbatim}

\minisec{Command line option \usertext{---nologo}}
This command line argument hides the splash screen when you start QGIS.

\subsection{QGIS GUI}\index{main window}
\label{label_qgismainwindow}

When QGIS starts, you are presented with the GUI as shown below
(the numbers 1 through 6 in yellow ovals refer to the six major areas of the
interface as discussed below):

\begin{figure}[ht]
   \begin{center}
   \caption{QGIS GUI with Alaska sample data \nixcaption (KDE)}
	 \label{fig:startup}
   \includegraphics[clip=true, width=17cm]{startup}
\end{center} 
\end{figure}

\textbf{Note:} Your window decorations (title bar, etc.) may appear
different depending on your operating system and window manager.\\

The QGIS GUI is divided into six areas:

\begin{tabbing}
1. Menu Bar \hspace{3cm}\= 4. Map View \\
2. Tool Bar \hspace{3cm}\> 5. Map Overview  \\
3. Map Legend \hspace{3cm}\> 6. Status Bar   
\end{tabbing}

These six components of the QGIS interface are described in more detail in
the following sections.

\subsubsection{Menu Bar}\label{label_menubar}
\index{menus}

The menu bar provides access to various QGIS features using a standard 
hierarchical menu. The top-level menus and a summary of some of the
menu options are listed below, together with the icons of the corresponding 
tools as they appear on the toolbar, as well as keyboard shortcuts.\footnote{Keyboard shortcuts can 
now be configured manually (shortcuts presented in this section are the defaults), using the Configure 
Shortcuts tool under Settings Menu.}
Although most menu options have a corresponding tool and vice-versa,
the menus are not organized quite like the toolbars. 
The toolbar containing the tool is listed after each menu option as a checkbox
entry. For more information about tools and toolbars, see Section \ref{label_toolbars}.

\begin{tabbing}
\hspace{5.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\hspace{1cm} Menu Option \> Shortcut \> Reference \> Toolbar\\
\end{tabbing}

\begin{itemize}
\item \mainmenuopt{File}
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionFileNew}{New Project}
	\> \keystroke{Ctrl+N}
	\> see Section \ref{sec:projects}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionFileOpen}{Open Project}
	\> \keystroke{Ctrl+O}
	\> see Section \ref{sec:projects}
	\> \dropmenucheck{File} \\
\dropmenuopt{Open Recent Projects}
	\>
	\> see Section \ref{sec:projects} \\
\dropmenuopttwo{mActionFileSave}{Save Project}
	\> \keystroke{Ctrl+S}
	\> see Section \ref{sec:projects}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionFileSaveAs}{Save Project As}
	\> \keystroke{Ctrl+Shift+S}
  \> see Section \ref{sec:projects}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionSaveMapAsImage}{Save as Image}
	\>
	\> see Section \ref{sec:output} \\
\dropmenuopttwo{mActionFilePrint}{Print Composer}
	\> \keystroke{Ctrl+P}
	\> see Section \ref{label_printcomposer}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionFileExit}{Exit} 
	\> \keystroke{Ctrl+Q} \\
\end{tabbing}

\item \mainmenuopt{Edit}
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionUndo}{Undo}
        \> \keystroke{Ctrl+Z}
        \> see Section \ref{sec:edit_existing_layer}
        \> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionRedo}{Redo}
        \> \keystroke{Ctrl+Shift+Z}
        \> see Section \ref{sec:edit_existing_layer}
        \> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionEditCut}{Cut Features} 
	\> \keystroke{Ctrl+X}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionEditCopy}{Copy Features}
	\> \keystroke{Ctrl+C}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionEditPaste}{Paste Features} 
	\> \keystroke{Ctrl+V}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionCapturePoint}{Capture Point}
	\> \keystroke{.}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionCaptureLine}{Capture Line}
	\> \keystroke{/}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
\dropmenuopttwo{mActionCapturePolygon}{Capture Polygon}
	\> \keystroke{Ctrl+/}
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
And Other Edit Menu Items
	\>
	\> see Section \ref{sec:edit_existing_layer} 
	\> \dropmenucheck{Digitizing} \\
%\dropmenuopt{Move Feature}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Split Features}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Delete Selected}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Add Vertex}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Move Vertex}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Delete Vertex}
%	\> \> \dropmenucheck{Edit} \\
%\dropmenuopt{Add Ring}\footnote{New since v0.9} 
%	\>
%	\> \dropmenucheck{Edit} \\
%\dropmenuopt{Add Island} \footnotemark[\value{footnote}] 
%	\>
%	\> \dropmenucheck{Edit} \\
\end{tabbing}


\item \mainmenuopt{View}
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionPan}{Pan Map}
	\>
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomIn}{Zoom In}
	\> \keystroke{Ctrl++}
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomOut}{Zoom Out}
	\> \keystroke{Ctrl+-}
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionSelect}{Select Features}
	\>
	\> \> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionIdentify}{Identify Features}
	\> \keystroke{I}
	\> \> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionMeasure}{Measure Line}
	\> \keystroke{M}
	\> \> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionMeasureArea}{Measure Area}
	\> \keystroke{J}
	\> \> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionOpenTable}{Zoom Full}
	\> \keystroke{F}
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomToLayer}{Zoom To Layer}
	\>
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomToSelected}{Zoom To Selection}
	\> \keystroke{Ctrl+J}
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomLast}{Zoom Last}
	\>
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopttwo{mActionZoomNext}{Zoom Next}
	\>
	\> \> \dropmenucheck{Map Navigation} \\
\dropmenuopt{Zoom Actual Size}
	\>
	\> \>  \\
\dropmenuopttwo{mActionMapTips}{Map Tips}
	\>
	\> \> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionNewBookmark}{New Bookmark}
	\> \keystroke{Ctrl+B}
	\> see Section \ref{sec:bookmarks} 
\> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionShowBookmarks}{Show Bookmarks}
	\> \keystroke{B}
	\> see Section \ref{sec:bookmarks} 
	\> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionDraw}{Refresh}
	\> \keystroke{Ctrl+R}
	\> \> \dropmenucheck{Map Navigation} \\
\end{tabbing}

\item \mainmenuopt{Layer}
\begin{tabbing}
\hspace{5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionNewVectorLayer}{New Vector Layer}
	\> \keystroke{N}
	\>          	
	see Section \ref{sec:create shape}
	\> \dropmenucheck{Manage Layers} \\
\dropmenuopttwo{mActionAddNonDbLayer}{Add a Vector Layer}       
	\> \keystroke{V}
	\>          	
	see Section \ref{label_workingvector}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionAddRasterLayer}{Add a Raster Layer}       
	\> \keystroke{R}
	\>          	
	see Section \ref{label_raster}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionAddLayer}{Add a PostGIS Layer}      
	\> \keystroke{D}
	\>          	
	see Section \ref{label_postgis}
        \> \dropmenucheck{File} \\
\dropmenuopttwo{mActionAddSpatiaLiteLayer}{Add a SpatiaLite Layer}
        \> \keystroke{L}
        \>
        see Section \ref{label_spatialite}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionAddWmsLayer}{Add a WMS Layer}          
	\> \keystroke{W}
	\>          	
	see Section \ref{sec:ogc-wms}
	\> \dropmenucheck{File} \\
\dropmenuopttwo{mActionOpenTable}{Open Attribute Table}
	\> \>
	\> \dropmenucheck{Attributes} \\
\dropmenuopttwo{mActionToggleEditing}{Toggle editing}
	\> \>
	\> \dropmenucheck{Digitizing} \\
\dropmenuopt{Save As Shapefile}
	\\
\dropmenuopt{Save Selection As Shapefile}
	\\
\dropmenuopttwo{mActionRemoveLayer}{Remove Layer}
	\> \keystroke{Ctrl+D}
	\>          	
	\> \dropmenucheck{Manage Layers} \\
\dropmenuopt{Properties}
	\\
\dropmenuopttwo{mActionInOverview}{Add to Overview}
	\> \keystroke{O}
	\>          	
	\> \dropmenucheck{Manage Layers} \\
\dropmenuopttwo{mActionAddAllToOverview}{Add All To Overview}
	\> \keystroke{+}
	\>          	
	\\
\dropmenuopttwo{mActionRemoveAllFromOverview}{Remove All From Overview}
	\> \hspace{1cm}\keystroke{-}
	\>          	
	\\
\dropmenuopttwo{mActionHideAllLayers}{Hide All Layers}
	\> \keystroke{H}
	\>          	
	\> \dropmenucheck{Manage Layers} \\
\dropmenuopttwo{mActionShowAllLayers}{Show All Layers}
	\> \keystroke{S}
	\>          	
	\> \dropmenucheck{Manage Layers} \\
\end{tabbing}

\item \mainmenuopt{Settings}
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopt{Panels}  
	\>           
	\>          	
	\\
\dropmenuopt{Toolbars}  
	\>           
	\>          	
	\\
\dropmenuopt{Toggle Fullscreen Mode}  
	\>
	\>          	
	\\
\dropmenuopttwo{mActionProjectProperties}{Project Properties}  
	\> \keystroke{P}
	\> see Section \ref{sec:projects}
	\\
\dropmenuopttwo{mActionCustomProjection}{Custom CRS}   
	\> \> see Section \ref{sec:customprojections}
	\\
\dropmenuopttwo{mActionOptions}{Configure shortcuts}
        \>
        \>
        \\
\dropmenuopttwo{mActionOptions}{Options}             
\> \>          	
see Section \ref{subsec:gui_options}
	\\
\end{tabbing}

\item \mainmenuopt{Plugins} - (Futher menu items are added by plugins as they are loaded.)
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionShowPluginManager}{Manage Plugins}          	   
	\> \> see Section \ref{sec:managing_plugins} \dropmenucheck{Plugins}
	\\
	\dropmenuopt{Python Console}
        \> \>
        \\
\end{tabbing}          	

\item \mainmenuopt{Help}
\begin{tabbing}
\hspace{4.5cm}\=\hspace{3cm}\=\hspace{3.5cm}\= \kill
\dropmenuopttwo{mActionHelpContents}{Help Contents}
	\> \keystroke{F1}
	\>           	
	\> \dropmenucheck{Help}\\
\dropmenuopttwo{mActionQgisHomePage}{QGIS Home Page}
	\> \keystroke{Ctrl+H}
	\>          	
	\\
\dropmenuopttwo{mActionCheckQgisVersion}{Check QGIS Version}
	\\
\dropmenuopttwo{mActionHelpAbout}{About}
	\\
\end{tabbing}

\end{itemize}

\textbf{Note:} \nix The Menu Bar items listed above are the default ones in KDE window
manager. In GNOME, Settings menu is missing and its items are to be found
there:
\begin{tabbing}
\dropmenuopttwo{mActionProjectProperties}{Project Properties} \hspace{3cm}\=
\dropmenucheck{File menu} \\
\dropmenuopttwo{mActionOptions}{Options} \hspace{3cm}\>
\dropmenucheck{Edit}\\
\dropmenuopttwo{mActionCustomProjection}{Custom CRS}\hspace{3cm}\>
\dropmenucheck{Edit} \\
\dropmenuopt{Panels} \hspace{3cm}\>
\dropmenucheck{View} \\
\dropmenuopt{Toolbars}   \hspace{3cm}\>
\dropmenucheck{View} \\
\dropmenuopt{Toggle Fullscreen Mode} \hspace{3cm}\>
\dropmenucheck{View}
\end{tabbing}

%See Appendix \ref{app_menu} for complete descriptions of the menu items.

\subsubsection{Toolbars}\label{label_toolbars}
\index{toolbars}

The toolbars provide access to most of the same functions as the menus,
plus additional tools for interacting with the map. Each toolbar item has
popup help available. Hold your mouse over the item and a short description of
the tool's purpose will be displayed. 

Every menubar can be moved around according to your needs. Additionally every
menubar can be switched off using your right mouse button context menu holding
the mouse over the toolbars.

\begin{Tip}
\caption{\textsc{Restoring toolbars}} \index{layout!toolbars}
\qgistip{If you have accidentally hidden all your toolbars, you can get them
back by choosing menu option \mainmenuopt{Settings} > \dropmenuopt{Toolbars}.}
\end{Tip}

\subsubsection{Map Legend}\label{label_legend}
\index{legend}

The map legend area is used to set the visibility and z-ordering of layers.
Z-ordering means that layers listed nearer the top of the legend are drawn
over layers listed lower down in the legend. The checkbox in each legend
entry can be used to show or hide the layer.\index{layer!visibility}

Layers can be grouped in the legend window by adding a layer group and dragging layers 
into the group. To do so, move the mouse pointer to the legend window, right click, choose \dropmenuopt{Add group}. 
A new folder appears. Now drag the layers onto to the folder symbol. It is then possible to toggle the 
visibility of all the layers in the group with one click. To bring layers out of a group, move 
the mouse pointer to the layer symbol, right click, and choose \dropmenuopt{Make to toplevel item}. To give the folder a 
new name, choose \dropmenuopt{Rename} in the right click menu of the group.

The content of the right mouse button context menu depends on whether the loaded legend item you hold your 
mouse over is a raster or a vector layer. For GRASS vector layers the \dropmenuopt{toggle editing} is not 
available. See section \ref{grass_digitising} for information on editing GRASS vector layers. 

\begin{itemize}

\item \textbf{Right mouse button menu for raster layers}
\begin{itemize}
\item \dropmenuopt{Zoom to layer extent}
\item \dropmenuopt{Zoom to best scale (100\%)}
\item \dropmenuopt{Show in overview}
\item \dropmenuopt{Remove}
\item \dropmenuopt{Properties}
\item \dropmenuopt{Rename}
\item \dropmenuopt{Add Group}
\item \dropmenuopt{Expand all}
\item \dropmenuopt{Collapse all}
\item \dropmenuopt{Show file groups}
\end{itemize}

\item \textbf{Right mouse button menu for vector layers}
\begin{itemize}
\item \dropmenuopt{Zoom to layer extent}
\item \dropmenuopt{Show in overview}
\item \dropmenuopt{Remove}
\item \dropmenuopt{Open attribute table}
\item \dropmenuopt{Toggle editing (not available for GRASS layers)}
\item \dropmenuopt{Save as shapefile}
\item \dropmenuopt{Save selection as shapefile}
\item \dropmenuopt{Properties}
%% \item \dropmenuopt{Make to toplevel item}
\item \dropmenuopt{Rename}
\item \dropmenuopt{Add Group}
\item \dropmenuopt{Expand all}
\item \dropmenuopt{Collapse all}
\item \dropmenuopt{Show file groups}
\end{itemize}

\item \textbf{Right mouse button menu for layer groups} 
\begin{itemize}
\item \dropmenuopt{Remove}
\item \dropmenuopt{Rename}
\item \dropmenuopt{Add Group}
\item \dropmenuopt{Expand all}
\item \dropmenuopt{Collapse all}
\item \dropmenuopt{Show file groups}
\end{itemize}

\end{itemize}

If several vector data sources have the same vector type and the same attributes, their 
symbolisations may be grouped. This means that if the symbolisation of one data source is 
changed, the others automatically have the new symbolisation as well. To group symbologies, open 
the right click menu in the legend window and choose \dropmenuopt{Show file groups}. The file groups of the 
layers appear. It is now possible to drag a file from one file group into another one. If this is done, 
the symbologies are grouped. Note that QGIS only permits the drag if the two layers are able to share 
symbology (same vector geometry type and same attributes).  

%% isn't included in Titan anymore, except for an "toggle overview"
%Each legend entry can show the following mini icons:
%
%\includegraphics[width=0.7cm]{pyramid} This is a raster
%that has pyramids built for it to improve rendering efficiency (see
%Section \ref{raster_pyramids}).\\
%\includegraphics[width=0.7cm]{no_pyramid} This is a
%raster that has no pyramid layers (see Section \ref{raster_pyramids}).\\
%\includegraphics[width=0.7cm]{inoverview} This layer is
%shown in the overview map area as well as in the main map window.\\
%\includegraphics[width=0.7cm]{editable} This is a vector
%layer that is currently enabled for editing.\\

\subsubsection{Map View}\label{label_mapview}
\index{map!view}

This is the 'business end' of QGIS - maps are displayed in this area! The
map displayed in this window will depend on the vector and raster layers you
have chosen to load (see sections that follow for more information on how to
load layers). The map view can be panned (shifting the focus of the map display
to another region) and zoomed in and out. Various other operations can be
performed on the map as described in the toolbar description above.  The map
view and the legend are tightly bound to each other - the maps in view reflect
changes you make in the legend area.  

\begin{Tip}\caption{\textsc{Zooming the Map with the Mouse
Wheel}}\index{zoom!mouse wheel}
\qgistip{You can use the mouse wheel to zoom in and out on the map. Place
the mouse cursor inside the map area and roll the wheel forward (away from you) to
zoom in and backwards (towards you) to zoom out. The mouse cursor position is the 
center where the zoom occurs. You can customize the behavior of the mouse
wheel zoom using the \tab{Map tools} tab under the \mainmenuopt{Settings} >\dropmenuopt{Options} menu.  }
\end{Tip}

\begin{Tip}\caption{\textsc{Panning the Map with the Arrow Keys and Space Bar}}\index{pan!arrow keys}
\qgistip{You can use the arrow keys to pan in the map. Place the mouse cursor 
inside the map area and click on the right arrow key to pan East, left arrow 
key to pan West, up arrow key to pan North and down arrow key to pan South. 
You can also pan the map using the space bar: just move the mouse while
holding down space bar.
}
\end{Tip}

\subsubsection{Map Overview}\label{label_mapoverview}
\index{map!overview}

The map overview panel provides a full extent view of layers added to it. It
can be selected under the menu \mainmenuopt{Settings} >\dropmenuopt{Panels}.
Within the view is a rectangle showing the current map extent. This allows
you to quickly determine which area of the map you are currently viewing. Note
that labels are not rendered to the map overview even if the layers in the
map overview have been set up for labeling. 

You can add a single layer to the overview by right-clicking on it in the
legend and select \checkbox{Show in overview}. You can also add layers to,
or remove all layers from the overview using the Overview tools on the toolbar.

If you click and drag the red rectangle in the overview that shows your 
current extent, the main map view will update accordingly.

\subsubsection{Status Bar}\label{label_statusbar}

The status bar shows you your current position in map coordinates (e.g.
meters or decimal degrees) as the mouse pointer is moved across the map view.
To the left of the coordinate display in the status bar is a small button that 
will toggle between showing coordinate position or the view extents of the 
map view as you pan and zoom in and out. 

A progress bar in the status bar shows progress of rendering
as each layer is drawn to the map view. In some cases, such as the gathering
of statistics in raster layers, the progress bar will be used to show the
status of lengthy operations. 

If a new plugin or a plugin update is available, you will see a message in the 
status bar. On the right side of the status bar is a small
checkbox which can be used to temporarily prevent layers being rendered to the
map view (see Section \ref{subsec:redraw_events} below). At the far right of
the status bar is a projector icon. Clicking on this opens the projection
properties for the current project.

\begin{Tip}\caption{\textsc{Calculating the correct Scale of your Map Canvas}}\index{scale!calculate}
\qgistip{When you start QGIS, degrees is the default unit, and it tells QGIS 
that any coordinate in your layer is in degrees. To get correct scale values, 
you can either change this to meter manually in the \tab{General} tab under 
\mainmenuopt{Settings} >\dropmenuopt{Project Properties} or you can select a project 
Coordinate Reference System (CRS) clicking on the
\toolbtntwo{mIconProjectionDisabled}{projector} 
icon in the lower right-hand corner of the statusbar. In the last case, the 
units are set to what the project projection specifies, e.g. '+units=m'.
}
\end{Tip}

\subsection{Rendering}\label{subsec:redraw_events}\index{rendering}

By default, QGIS renders all visible layers whenever the map canvas must be
refreshed. The events that trigger a refresh of the map canvas include:

\begin{itemize}
\item Adding a layer
\item Panning or zooming
\item Resizing the QGIS window
\item Changing the visibility of a layer or layers
\end{itemize}

QGIS allows you to control the rendering process in a number of ways.

\subsubsection{Scale Dependent Rendering}\index{rendering!scale dependent}
\label{label_scaledepend}

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

You can determine the scale values by first zooming to the level you want
to use and noting the scale value in the QGIS status bar.\index{scale}

\subsubsection{Controlling Map Rendering}\label{label_controlmap}

Map rendering can be controlled in the following ways:

\minisec{a) Suspending Rendering}\index{rendering!suspending}
\label{label_suspendrender}

To suspend rendering, click the \checkbox{Render} checkbox in the lower right
corner of the statusbar. When the \checkbox{Render} box is not checked, QGIS
does not redraw the canvas in response to any of the events described in
Section \ref{subsec:redraw_events}. Examples of when you might want to suspend
rendering include:

\begin{itemize}
\item Add many layers and symbolize them prior to drawing
\item Add one or more large layers and set scale dependency before drawing
\item Add one or more large layers and zoom to a specific view before drawing
\item Any combination of the above
\end{itemize}

Checking the \checkbox{Render} box enables rendering and causes and immediate
refresh of the map canvas.

\minisec{b) Setting Layer Add Option}\label{label_settinglayer}
\index{rendering!options}\index{layers!initial visibility}

You can set an option to always load new layers without drawing them. This
means the layer will be added to the map, but its visibility checkbox in the
legend will be unchecked by default. To set this option, choose
menu option \mainmenuopt{Settings} > \dropmenuopt{Options} and click on the
\tab{Rendering} tab. Uncheck the \checkbox{By default new layers added to the map 
should be
displayed} checkbox. Any layer added to the map will be off (invisible) by
default.

%\minisec{Stopping Rendering}\index{rendering!halting}
%\label{label_stoprender}
%
%To stop the map drawing, press the ESC key. This will halt the refresh of
%the map canvas and leave the map partially drawn. It may take a bit of time
%between pressing ESC and the time the map drawing is halted.
%
%\textbf{NOTE}: It is currently not possible to stop rendering - this was disabled 
%in qt4 port because of User Interface (UI) problems and crashes.

\minisec{c) Updating the Map Display During Rendering}
\label{label_updatemap}\index{rendering!update during drawing}

You can set an option to update the map display as features are drawn. By
default, QGIS does not display any features for a layer until the entire
layer has been rendered. To update the display as features are read from the
datastore, choose menu option \mainmenuopt{Settings} > \dropmenuopt{Options}
click on the \tab{Rendering} tab. Set the feature count to an
appropriate value to update the display during rendering. Setting a value of 0
disables update during drawing (this is the default). Setting a value too low
will result in poor performance as the map canvas is continually updated
during the reading of the features. A suggested value to start with is 500. 

\minisec{d) Influence Rendering Quality}
\label{label_renderquality}\index{rendering!quality}

To influence the rendering quality of the map you have 3 options. Choose menu 
option \mainmenuopt{Settings} > \dropmenuopt{Options} click on the 
\tab{Rendering} tab and select or deselect following checkboxes.

\begin{itemize}
\item \checkbox{Make lines appear less jagged at the expense of some drawing performance}
\item \checkbox{Fix problems with incorrectly filled polygons}
%%\item \checkbox{Continuously redraw the map when dragging the legend/map divider}
\end{itemize}


\subsection{Measuring}\label{sec:measure}\index{measure}

Measuring works within projected coordinate systems only (e.g., UTM). If 
the loaded map is defined with a geographic coordinate system
(latitude/longitude), the results from line or area measurements will be 
incorrect. To fix this you need to set an appropriate map coordinate system 
(See Section~\ref{label_projections}). 

\subsubsection{Measure length and areas}\index{measure:line length}\index{measure:areas}
\includegraphics[width=0.7cm]{mActionMeasure} 
QGIS is also able to measure real distances between given 
points according to a defined ellipsoid. To configure this, choose menu option 
\mainmenuopt{Settings} > \dropmenuopt{Options}, 
click on the \tab{Map tools} tab and choose the appropriate ellipsoid. There
you can also define a rubberband color and your preferred measurement units
(meters or feet). 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. \\
\includegraphics[width=0.7cm]{mActionMeasureArea} 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~\ref{snapping_tolerance}). 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. 

\begin{figure}[h]
\caption{Measure tools in action \nixcaption} \label{fig:measure}
\centering
   \subfigure[Measure lines] {\label{subfig:measure_line}\includegraphics[clip=true, width=0.3\textwidth]{measure_line}}\goodgap
   \subfigure[Measure areas]{\label{subfig:measure_area}\includegraphics[clip=true, width=0.3\textwidth]{measure_area}}
\end{figure}

\subsection{Projects}\label{sec:projects}\index{projects}

The state of your QGIS session is considered a Project.  QGIS
works on one project at a time.  Settings are either considered
as being per-project, or as a default for new projects (see
Section \ref{subsec:gui_options}). QGIS can save the state of your 
workspace into a project file using the menu options 
\mainmenuopt{File} > \dropmenuopttwo{mActionFileSave}{Save Project}
or \mainmenuopt{File} > \dropmenuopttwo{mActionFileSaveAs}{Save Project As}.

Load saved projects into a QGIS session using 
\mainmenuopt{File} > \dropmenuopttwo{mActionFileOpen}{Open Project}
or \mainmenuopt{File} > \dropmenuopt{Open Recent Project}.
If you wish to clear your session and start fresh, choose
\mainmenuopt{File} > \dropmenuopttwo{mActionFileNew}{New Project}.
Either of these menu options will prompt you to save the existing project
if changes have been made since it was opened or last saved.

The kinds of information saved in a project file include:

\begin{itemize}
\item Layers added
\item Layer properties, including symbolization
\item Projection for the map view
\item Last viewed extent
\end{itemize}

The project file is saved in XML format, so it is possible to edit
the file outside QGIS if you know what you are doing. The file format 
was updated several times compared to earlier QGIS versions. Project files 
from older QGIS versions may not work properly anymore. To be made aware of this, 
in the \tab{General} tab under \mainmenuopt{Settings} > \dropmenuopt{Options} 
you can select \checkbox{Warn when opening a project file saved with an older 
version of QGIS}.


\minisec{Project Properties}
In the properties window for the project (under \nix{\mainmenuopt{File} > \dropmenuopt{Project Properties}} or  \win{\mainmenuopt{Settings} > \dropmenuopt{Project Properties} } you set project specific options. These include:
\begin{itemize}
 \item In the \tab{General} tab the Project title, units, and the option to save relative paths to layers. In addition the topological editing, and snapping options are set here.
\item The \tab{CRS} Coordinate Reference System tab enables you to choose the CRS for this project, and to enable on-the-fly reprojection of vector layers when displaying layers from a different CRS.
\item With the third \tab{Identifiable layers} tab you set (or disable) which layers will respond to the identify tool. (See the Map tools paragraph from the  \ref{subsec:gui_options} section to enable identifying of multiple layers.)
\end{itemize}
 
\subsection{Output}\label{sec:output}\index{output!save as image!print composer!quick print}
There are several ways to generate output from your QGIS session.
We have discussed one already in Section \ref{sec:projects}: saving as a project file. 
Here is a sampling of other ways to produce output files:
\begin{itemize}
\item Menu option \dropmenuopttwo{mActionSaveMapAsImage}{Save as Image} opens a
file dialog where you select the name, path and type of image (PNG or JPG format). From 1.1.0
release, a world file with extension PNGW or JPGW saved in the same folder georeferences the image.
\item Menu option \dropmenuopttwo{mActionFilePrint}{Print Composer} opens a dialog 
where you can layout and print the current map canvas (see Section~\ref{label_printcomposer}).
\end{itemize}


\subsection{GUI Options}\label{subsec:gui_options}
\includegraphics[width=0.7cm,clip=true]{mActionOptions} 
Some basic options for QGIS
can be selected using the \dialog{Options} dialog. Select the 
menu option \mainmenuopt{Settings} >
 \dropmenuopttwo{mActionOptions}{Options}. The tabs where you can 
optmize your options are:

\minisec{General Tab}

\begin{itemize}
\item \checkbox{Promt to save project changes when required}
\item \checkbox{Warn when opening a project file saved with an older version of QGIS}
\item Change Selection and backgroud Color
\item Change the icon theme (choose between default, classic, gis and nkids)
\item \checkbox{Capitalise layer names in legend}
\item \checkbox{Display classification attribute names in legend}
\item \checkbox{Hide splash screen at startup}
\item \checkbox{Open identify results in a dock window (QGIS restart
required)}
\item \checkbox{Open attribute table in a dock window}
\item \checkbox{Add PostGIS layers with double click and select in extended mode}
% \item Define attribute table behavior (choose between show all features, show
% selected features and show features in current canvas)
\end{itemize}

\minisec{Rendering Tab}

\begin{itemize}
\item \checkbox{By deafult new layers added to the map should be displayed}
\item Define number of features to draw before updating the display.
\item \checkbox{Make lines appear less jagged at the expense of some drawing performance}
\item \checkbox{Fix problems with incorrectly filled polygons}
% \item \checkbox{Continously redraw when dragging the legend/map divider} 
\end{itemize}

\minisec{Map tools Tab}

\begin{itemize}
\item The Mode setting determines which layers will be shown by the Identify tool. By switching to \usertext{Top down} instead of \usertext{Current layer} then attributes for all identifiable layers (See the Project properties section under: \ref{sec:projects} to set which layers are identifiable) will be show with the Identify tool.
\item Define Search Radius as a percentage of the map width
\item Define Ellipsoid for distance calculations
\item Define Rubberband Color for Measure Tools
\item Define preferred measurement units (meter or feet)
\item Define Mouse wheel action (Zoom, Zoom and recenter, Zoom to mouse cursor, Nothing)
\item Define Zoom factor for wheel mouse
\end{itemize}

\minisec{Overlay}

\begin{itemize}
\item Define placement algorithm for labels (choose between central point
(standard), chain, popmusic tabu chain, popmusic tabu and popmusic chain)
\end{itemize}

\minisec{Digitizing Tab}

\begin{itemize}
\item Define Rubberband Color and line width for Digitizing
\item Define default snap mode (to vertex, to segment, to vertex and segment)
\item Define default snapping tolerance in layer units
\item Define search radius for vertex edits in layer units
\item \checkbox{Show markers only for selected features}
\item Define vertex marker style (Cross, semi transparent circle or none) and
size
\item \checkbox{Suppress attributes pop-up windows after each created feature}
\end{itemize}

\minisec{CRS Tab}

\begin{itemize}
\item \checkbox{Prompt for Coordinate Reference System (CRS)}
\item \checkbox{Project wide default Coordinate Reference System (CRS) will be used}
\item \checkbox{Global default Coordinate Reference System (CRS) displayed below will be used}
\item Select global default Coordinate Reference System (CRS)
\end{itemize}

\minisec{Locale Tab}

\begin{itemize}
\item \checkbox{Overwrite system locale and use defined locale instead}
\item Information about active system locale
\end{itemize}

\minisec{Proxy Tab}

\begin{itemize}
\item \checkbox{Use proxy for web access} and define host, port, user, and password.
\item Set the \dropmenuopt{Proxy type} according to your needs
 \begin{itemize}
  \item \dropmenuopt{Default Proxy}: Proxy is determined based on the application proxy set using
  \item \dropmenuopt{Socks5Proxy}: Generic proxy for any kind of connection. Supports TCP, UDP, binding to a port (incoming connections) and authentication.
  \item \dropmenuopt{HttpProxy}: Implemented using the "CONNECT" command, supports only outgoing TCP connections; supports authentication.
  \item \dropmenuopt{HttpCachingProxy}: Implemented using normal HTTP commands, it is useful only in the context of HTTP requests
  \item \dropmenuopt{FtpCachingProxy}: Implemented using an FTP proxy, it is useful only in the context of FTP requests
 \end{itemize}
\end{itemize}

Excluding some URLs can be added to the textbox below the proxy-settings (see
fig. \ref{fig:proxy-settings}) by pressing the \button{Add}-button. After that
double-click into the just created URL-field and enter the URL you would like
to exclude from using the proxy. Obviously the button \button{Remove} removes the selected
entry.

If you need more detailed information about the different proxy-settings,
please refer to the manual of the unterlaying QT-library-documentation at
\url{http://doc.trolltech.com/4.5/qnetworkproxy.html#ProxyType-enum}.

\begin{figure}[ht]
   \begin{center}
   \caption{Proxy-settings in QGIS \nixcaption}
   \includegraphics[clip=true, width=10cm]{proxy-settings}
   \label{fig:proxy-settings}
\end{center} 
\end{figure}

\begin{Tip} \caption{\textsc{Using Proxies}}
\qgistip{Using proxies can sometimes be tricky. It is useful to 'trial and
error' the above proxy types and check if they succeed in your case.
}
\end{Tip}

You can modify the options according to your needs. Some of the changes may 
require a restart of QGIS before they will be effective.

\begin{itemize}
\item \nix{settings are saved in a texfile: \$HOME/.config/QuantumGIS/qgis.conf}
\item \osx{you can find your settings in: \$HOME/Library/Preferences/org.qgis.qgis.plist}
\item \win{settings are stored in the registry under:}
\begin{verbatim}
\\HKEY\CURRENT\USER\Software\QuantumGIS\qgis
\end{verbatim}
\end{itemize}


\subsection{Spatial Bookmarks}\label{sec:bookmarks}
\index{bookmarks}
\index{spatial bookmarks|\see{bookmarks}}

Spatial Bookmarks allow you to ``bookmark'' a geographic location and return to it later.

\subsubsection{Creating a Bookmark}
To create a bookmark:
\begin{enumerate}
\item Zoom or pan to the area of interest.
\item Select the menu option \mainmenuopt{View} > \dropmenuopt{New Bookmark} or press \keystroke{Ctrl-B}.
\item Enter a descriptive name for the bookmark (up to 255 characters).
\item Click \button{OK} to add the bookmark or \button{Cancel} to exit without adding the bookmark.
\end{enumerate}

Note that you can have multiple bookmarks with the same name.

\subsubsection{Working with Bookmarks}
To use or manage bookmarks, select the menu 
option \mainmenuopt{View} > \dropmenuopt{Show Bookmarks}.
The \dialog{Geospatial Bookmarks} dialog allows you to zoom to or delete a bookmark.
You can not edit the bookmark name or coordinates.

\subsubsection{Zooming to a Bookmark}
From the \dialog{Geospatial Bookmarks} dialog, select the desired bookmark by clicking on it, 
then click \button{Zoom To}.
You can also zoom to a bookmark by double-clicking on it.

\subsubsection{Deleting a Bookmark}
To delete a bookmark from the \dialog{Geospatial Bookmarks} dialog, click on it then click
 \button{Delete}.
Confirm your choice by clicking \button{Yes} or cancel the delete by clicking \button{No}.


