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3.1. ESRI Shapefiles
Figure 3.1.: Add Vector Layer Dialog
Selecting a shapefile from the list and clicking Open loads it into QGIS. Figure 3.3 shows QGIS after loading
the alaska.shp file.
QGIS Tip 8 L AYER C OLORS
When you add a layer to the map, it is assigned a random color. When adding more than one layer at a time,
different colors are assigned to each layer.
Once loaded, you can zoom around the shapefile using the map navigation tools. To change the symbology
of a layer, open the Layer Properties dialog by double clicking on the layer name or by right-clicking on
the name in the legend and choosing Properties
information on setting symbology of vector layers.
I from the popup menu. See Section 3.4.1 for more
QGIS Tip 9 L OAD LAYER AND PROJECT FROM MOUNTED EXTERNAL DRIVES ON OS X
On OS X, portable drives that are mounted besides the primary hard drive do not show up under File
Open
Project as expected. We are working on a more OSX-native open/save dialog to fix this. As a workaround
you can type ’/Volumes’ in the File name box and press return. Then you can navigate to external drives and
network mounts.
3.1.2. Improving Performance
To improve the performance of drawing a shapefile, you can create a spatial index. A spatial index will improve
the speed of both zooming and panning. Spatial indexes used by QGIS have a .qix extension.
Use these steps to create the index:
– Load a shapefile.
– Open the
Layer Properties
dialog by double-clicking on the shapefile name in the legend or by
right-clicking and choosing Properties
I from the popup menu.
– In the tab General click the Create Spatial Index button.
3.1.3. Loading a MapInfo Layer
To load a MapInfo layer, click on the
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Add Vector Layer toolbar bar button or type Ctrl-Shift-V
QGIS 1.6.0 User Guide