Lembo A., Flint E., O'Brien J., Nohe A. ©Eastern Shore Regional GIS Cooperative 2013
Introduction to Quantum GIS An Overview: Workbook 1
Dr. Arthur J Lembo Jr., Eric Flint, John O'Brien, Alex Nohe
3/19/2013
Quantum GIS is a fully functional and modern Open Source desktop GIS package. This introduction to Quantum GIS will illustrate some of its basic capabilities through application of a practical tutorial.
Introduction to Quantum GIS
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Setup: To complete the following workbook, Quantum GIS must be installed on your computer. It can
be downloaded at: http://hub.qgis.org/projects/quantum-gis/wiki/Download
Additionally you must download a local copy of the data files from github at: https://github.com/esrgc/qgistraining
Task One: 1) Open Quantum
2) Enable on the fly transformations
Settings Project Properties
Check Box for “Enable ‘on the fly’ CRS transformations”
Enable on the fly transformations to ensure that all data added to the map will be re-projected to UTM Zone 17
OK
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3) Add Data ** For this exercise we will be loading both .shp and .dbf files Layer
Add Vector Layer
Select appropriate Source type * For this workshop we will select file
Select Browse Select data to import from appropriate file path
** File type will default to .shp – When loading text files (.dbf) with .shp files make sure that you select the ‘All Files Types’ when browsing for data.
* For this workshop the file path will be: ___________________________________________ * For this workshop the data needed is: bk79.shp; firestat.shp; istates.shp; richland.shp; rr.shp; schools.shp; tri92.shp; ushwys.shp; databk79.dbf
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Open * Features will render to map * Adjust the precedence of the features as needed for readability i.e. points on top of polygons
* Adjust symbology as needed/desired R Feature Properties
*This window will open
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* Select changes…changes may be previewed by selecting apply OK
Task Two: Locational and Demographics Analysis Lindau Chemical experienced an explosion at its Columbia plant in September 1997. Five workers were injured but no chemicals were released and no one in the community was affected. It did raise concerns among city leaders that, given Lindau’s relative proximity to downtown Columbia, the plant may pose a risk to citizens. Indeed, the plant uses large amounts of ammonia in its processes and ammonia has a general impact area of five miles when released. So, how many Richland County schools could be impacted by an ammonia release from Lindau Chemical? Using the bk79 shapefile, calculate the number of people that would have to be evacuated if an ammonia spill occurred.
1) Isolate Lindau Chemical from other TRI facilities using a query R on tri92.shp Query…
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* When Query Builder GUI opens: Name under ‘Fields’ = under ‘Operators’ Sample Button under ‘Values’ (This will generate a values list for ‘Name”) Lindau Chemical * SQL where clause should now read: “NAME” = ‘LINDAU CHEMICAL’
OK
2) Create Buffer Zone Vector Geoprocessing Tools Buffers Input vector layer tri92 Use only selected features Buffer Distance = 8046.72 * Map distance is meters: 1 mile = 1609.34 meters Dissolve buffer results Output shapefile Browse appropriate path
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OK * This message will appear
Yes * New map display
Introduction to Quantum GIS
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* Adjust properties as desired R richland_buff properties Style Transparency / Color as desired
* New map display
Introduction to Quantum GIS
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3) Select Schools in Buffer Vector Spatial Query Spatial Query
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Select source features from = schools Where the feature =Within Reference features of = richland_buff And use the results to = Create new Selection Apply
* * Number of schools contained in ‘Selected Features’ = 24 Close
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* New map display
* New Feature Class = schools selected * This New Feature Class is created in Virtual Memory Only! Tables cannot be edited, must be saved as a shapefile if editing capabilities are needed. See task 3 for instructions on converting virtual feature classes to shapefiles* * Attribute Table can be used for Amount/Addresses…
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4) Calculate number of people within Buffer zone for evacuation
Vector Spatial Query Spatial Query
Select source features from = bk79 Where the feature = Within Reference features of = richland_buff And use the results to = Create new Selection Apply
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Close * New map display
Vector Analysis Tools Basic Statistics
Input Vector Layer = bk79 selected Target field = POP OK
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* Number of People to evacuate in case of Lindau Chemical Ammonia Spill = 94024
