Starting the QGIS Program. Exercise 1: Exploring QGIS

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1 Exercise 1: Exploring QGIS In this exercise you will learn how to open maps, manipulate layers, add spatial data, change symbols, and navigate within QGIS. You will also learn to repair broken data links. Contents Starting the QGIS Program... 1 Adding Layers to a map... 4 Open and Close Panels... 8 Change map layer symbol properties... 9 Grouping map layers Navigating in the map window (Pan and Zoom) Save project Repair Data Sources Starting the QGIS Program If QGIS Desktop is pinned to your start menu, simply click on the icon. Otherwise, in the Start Menu, select All apps and navigate to the QGIS folder. Select any of the QGIS desktop applications. More information on the QGIS Graphical User Interface (GUI) is available at 1

2 If the QGIS Tips window opens, click on OK. You can prevent the tips window from opening in the future by checking the box next to I ve had enough.. Or, you can browse through the tips using the NEXT and PREVIOUS buttons. 2

3 How to open QGIS: Windows 7 Enterprise and earlier version of QGIS (ESSEN). The screen shots in the following workbook are from a 64 bit laptop running Windows 10 and the most recent version of QGIS. When you open an old version of QGIS you will see a message at the bottom indicating that there is an update available. After you install the new version you can uninstall the old one. 3

4 If you have never used QGIS or have never saved a project, the Recent Projects window should be empty. Click on the Project menu and select New to start a new project. The map window becomes blank. Adding Layers to a map In the Browser Panel you can navigate to where the data are stored for this class. In the example below, the data are in c:/users/ /CrimeMapping/Intro. Use the Browser Panel exactly as you would use File Explorer (or My Computer) in Windows. The data that we will add are in the gis_data folder. We will be adding vector shape files from ESRI s ArcGIS. Click on the Add Vector Layer tool on the left side of the QGIS window. 4

5 Then click on the Browse button in the Add Vector Layer window and navigate to your gis_data folder. An ESRI shapefile actually consists of several files with different file extensions. The.shp extension is the spatial data,.dbf is the tablular data (attributes of the features),.shx is the spatial index information,.prj is the projection information etc. When you add a layer using ESRI ArcGIS (ArcMap) all of the files associated with the database are added to the application. In QGIS, you add files based on their extension. 5

6 Scrolling through the list of files in the gis_data folder reveals that there are several spatial databases (apartments, atms, bus routes, bus stops..) however, there is no information about the data type (point, line polygon, etc.). Select Gotham.shp, school_points.shp, and streets.shp. Press and hold the CTRL key on your keyboard to make multiple selections. Then click the Open button twice. Make sure you check the actual extension on the.shp files. Typically there are two that appear to be.shp files but when you look at the Type column you will see that one is actually XML. The three layers are drawn in the map window. You cannot see the streets or the school points because they are covered by the Gotham city polygon. Map layers are drawn from the bottom up. In the Layers Panel the X next to a layer s name indicates that it is visible meaning it is drawn. 6

7 Click and hold the left mouse button down on a layer s name, then drag it to change the drawing order. To see the streets and school_points, drag the Gotham layer to the bottom of the list. 7

8 Open and Close Panels QGIS is comprised of a set of panels and a map window. The panels shown in the previous screen shots include the Browser Panel, the Layers Panel, and the Shortest Path panel. You can close a panel by clicking on the X in the top right corner of the panel window. You can undock a panel clicking the button to the left of the X in the panel window. Re-dock the window by dragging it back to the panels area. 8

9 Use either the View menu or right click on the button to the left of the X in a panel window to turn panels on and off. Change map layer symbol properties The three map layers added to the map window are drawn using default symbols. You can change these symbols by right clicking on a layers name in the layer panel and selecting Properties from the drop down menu. Change the streets from blue to black lines. Select Style in the Layer Properties window. Click on the arrow next to the color and pick black. 9

10 You can change the width of the lines or use a symbol library to characterize how the features are drawn. Another way to change the style of a symbol is simply to select the layer and click on the Open the layer styling dock button on the far left of the Layers Panel. 10

11 In the window below, the school_points layer is not visible (no X adjacent to the name), the Gotham layer is selected, and the layer styling dock appears on the right side of the map window. Change the color to a light gray and set the transparency to 50%. Click on the down arrow next to Color and select Choose color In the Select Color window, drag the intersecting lines around until the Current color is a light gray. Then click OK. Drag the pointer on the Transparency bar until it reads 50%. 11

12 You can close or undock the Layer Styling Panel just like any other panel. You can also change the layer to be styled by simply selecting another one from the drop down at the layer name. The map below shows the school layer symbol changed to a red triangle in the Layer Styling window. 12

13 Grouping map layers You can group layers to make them easier to manage in the map window. We will create a new map group for transportation layers in our map. First, from the gis_data folder add the bus routes.shp and bus stops.shp files to the map. 13

14 Next, click on the Add Group button in the Layers Panel. Change the name of the group from group1 to Transportation. Click on the streets layer and drag it to the paper clip symbol next to the group name. Do the same for bus routes and bus stops. These layer names now appear indented under the Transportation Group. When you click on the X next to the group name, all layers in the group become invisible. Expand or contract the layer names in the group using the + or symbol next to the group name. 14

15 Click and drag the streets layer from the Transportation group. Right click on the Transportation Group and select Remove. The group and the two layers in it will be removed from the project. Key Concepts Adding data to a map Expand and collapse layers using the +/- icons Turn layers on and off using the checkbox Work with multiple layers using the Ctrl key Using drag-and-drop to reorder layers Create and modify layer groups 15

16 Navigating in the map window (Pan and Zoom) QGIS offers a group of tools in the navigation toolbar that you can use to manipulate the map in the map window. These tools are (from left to right): Touch zoom and pan: Used for touch screen manipulations. Pan Map: Holding left mouse button down drag the map focus on area of interest. Pan Map to Selection: re-centers map on selected features Zoom in: Draw a box around the area you want to zoom in to. Left click, holding left mouse button down drag a rectangle around area of interest, release mouse button to zoom. 16

17 Zoom out: Draw a box around the area you want to zoom out from. Left click, holding left mouse button down drag a rectangle around area of interest, release mouse button to zoom out. 17

18 Zoom to Native Resolution (100%): Use for raster layers to zoom to full extent. Zoom Full: Zooms to full extent of all layers. Zoom to Selection: You must have a selection to zoom to. Click on a layer in the Layers Panel from which you want to select features. Use the Select Tool to select some of the features in that layer. The default selection method is point and click (or drag a rectangle) but you may change the method by clicking on the arrow next to the select tool. 18

19 Use Zoom to Selected tool to zoom in on these two schools. Zoom to Layer: Zooms to the extent of the layer selected in the Layers Panel. Zoom Last: Go back to previous view Zoom Next: Only active if zoom last has been used. Return to view that preceded current view. 19

20 New Bookmark: Bookmark the current view. In the following example labels for the school owner have been turned on (from the layer Properties /Labels window) and the map window is zoomed into a cluster of schools on the east side of Gotham. When you click New Bookmark, a bookmark appears in the Spatial Bookmark Panel. The bookmark is renamed eastside schools. As you move around the map (Panning, zooming in/out etc.) you can return to this exact view by selecting the bookmark in the Spatial Bookmark Panel, then clicking on the Zoom to Bookmark tool in the top left of this panel. 20

21 Show Bookmarks: Opens up the spatial bookmarks panel Refresh: redraws the map in the map window Save project To save this project, go to the Project Menu and select Save As. 21

22 Navigate to the crime_mapping_class/exercises folder and name the project exercise1.qgs and click Save. The name of the project will appear in the top left corner once it is saved. Repair Data Sources Occasionally, the name or path to features in your project might change. Open exercise1b in the crime_mapping_class/exercises folder. In the following example, the gis_data folder was renamed gisdata the underscore was removed from the folder name. If there has been a change to the data source, when you open a project a Handle bad layers window will appear. This window contains a list of the layers and the saved data source information. 22

23 Select a file from the list and click on Browse. Navigate to where the file is saved. Click Open. Once you have fixed the source for all files, click Apply in the Handle bad layers window. If all data sources are correct the Handle bad layers window will be empty. If there are still bad sources, the names will appear in red and you should fix them. When finished, click OK. Key Concepts Map navigation Zoom in Zoom out Pan Back and Forward Zoom to selected Selecting features Spatial bookmarks Repairing data sources 23