Module 1: GIS Workshop Concept and Practice

1. GIS Workshop
Concepts and Practice
Nancy Warren, MPH
With Contributions from:
Nathan Heard, DSc
Hilary Spindler, MPH
Sarah Gutin
Ryan Keating

2. Goal
• Understand important GIS concepts and
how to utilize them through Quantum
GIS (QGIS), an open source software
package

3. Objectives:
• Understand basic GIS concepts
• Navigate GIS interface
• Locate GIS data on the web and
identify reliable data sources
• Add data to GIS software and
prepare vector GIS data
• Convert text-based data to a GIS
format

4. Objectives (cont’d)
• Create thematic maps with multiple
variables
• “Clip” map sections
• Test maps with Google raster data
• Demonstrate competency with basic
QGIS

5. Session one:
• Overview
• Basic QGIS installation and navigation
• Loading shapefiles and navigating
shapefiles

6. Definition of GIS
• Geographical Information System
– A map connected to a database
• A computerized database management
system for analysis and display of spatial data
• A system of data and tools

7. Why GIS?
Isn’t this chart enough?
Province HIV prev: women
Cabo delgado 9.5
Gaza 29.9
Inhambane 10
Manica 15.6
Maputo 20
Nampula 5.5
Niassa 3.3
Sofala 17.8
Tete 8
Zambezia 15.3

8. Why GIS?
see it to understand it:
HIV prevalence in women

9. Functions of GIS
• Visualization and Mapping
• Spatial database management
• Spatial Analysis

10. What GIS Applications Do:
• Automate geographic data
– Produce maps
– Calculate areas, distances, route lengths
• Integrate data (i.e. property maps and satellite photos)
• Communicate complex spatial patterns

11. What GIS Applications Do
• Answer spatial queries
– (how many HIV+ people live further than 10 km
from the PMTCT clinic 24 de Julho in the
Zambezia province?)
• Perform complex spatial modeling
– (“what if” scenarios for resource management –
where to put new sites, transportation – how to get
resources to people in need, etc.)

12. Difficulties
• Difficulty of database creation
• Integration of data from diverse sources can
result in poor overall accuracy if not well
managed
• Representation of dynamic data – flows,
dispersion, people, time can be problematic

13. The GIS Data Model: Implementation
Geographic Integration of Information
Layers
By
Organized
Is
Data

14. Data Organization in GIS
• Each layer contains
one specific type of
information.
• Layers are
integrated using
their geographic
location on the
earth’s surface as
the organizing
principle

15. Layers can be represented as Rasters or
Vectors:
•Vector create feature layers
– Point
– Lines (direction and length)
– Polygons (area, centroids,
and perimeter)
•Raster create surface layers
– Records information about
each element on a fixed grid
as pixels (E.g.: Satellite
images, aerial photos)

16. Vector vs. Raster

17. Table or attribute data
Tables - contain data for places that can
be converted to GIS files and mapped
• If each data record contains unique ID
codes for each place, those records can
be joined to their corresponding
features in a GIS file and mapped.
• If the data contains coordinates like
latitude and longitude, the data can be
plotted and converted to a vector file.

18. Geodatabase
•A geodatabase
(short for geographic
database) is a
physical store of
geographic
information in the
form of features and
classes inside a
database
management system
(DBMS).

19. Linking data: JOIN
GIS systems maintain
• spatial and
• attribute data
separately,
• then “join” them for
display or analysis

20. JOINing our data:
Geographic data links
• Spatial data Attribute data

21. Metadata: an important
part of GIS infrastructure
• Describes information resources
• Enables data exchange, efficient use of
(existing) resources
Source: http://www.esi.utexas.edu/gk12/workshops/gis/ppts.php

22. Quantum GIS (QGIS) - freeware
• Open Source GIS software that runs on
Linux, Mac, Unix and Windows
• First released in 2002 – Mature program
– Strong Online Community
• Regular updates and releases
• Compatible with: MySQL, SQLite,
• Freestanding module that can be linked

23. QGIS
• View and explore spatial data
– Can use files from other programs: Google
maps, Open Street Maps, WMS, GRASS
• Map Data (e.g., prevalence, population)
• Create/edit spatial data (e.g., from GPS
unit)
• Perform Spatial Analysis (e.g., network
analysis)

24. QGIS: Disadvantages
• Learning curve is higher
• No raster or vector data already
included -- must import
• No raster or vector data integrated --
must ensure quality
• Importing table (attribute) data is a two
step process

25. QGIS relies on other sources
for map layers
• User needs to import mapping layers
into the system from their own sources
and
• user needs to ensure quality of layers
-DIVA GIS
-QGIS

26. Open Streets Maps and
Google Maps
– These offer layers that can be imported
and used with all the other GIS software
we will discuss today
– Can be manipulated to show a variety of
features

27. Google Maps and Google
Earth
• Disadvantages:
– No static layers that can be imported and
used, because layers are constantly being
updated
– Requires strong connection to web in order
to import layers

28. 5 minute QGIS Tour

29. When you first start up
QGIS, this is what you will
see.
This is called the QGIS
Graphical User Interface,
or GUI
It may look bare now, but
by the end of this week,
the GUI will look a little
more like….

30. This!

31. Lets take a moment before
going any further and go
through the front-end
components of QGIS.
Becoming familiar and
comfortable will make
learning the ins-and-outs
of QGIS a little easier

32. We can think about QGIS in terms
of a geodatabase.
We can see all of our
vector and raster data in
the left hand layers
window
Whenever we load or
create a new layer, it will
appear in this window

33. This is where our data will
be visually represented.
In this example we can see
two types of spatial data.
Raster and Vector.

34. In terms of vector data we
can see two types: line
and point data.
Both of these visual data
elements are also visible
in the Layers window

35. The raster data we can see
here is this large satellite
image of Vilankulos.

36. What do we need before
starting?
1. QGIS Software
2. Data (Shapefiles)
3. Plug-ins

37. QGIS: Required Software
• QGIS Desktop (Standalone Installer)
This tutorial was designed with version 1.7.3
WROCLAW. In an effort to improve quality
control, QGIS next version (LISBOA) has
made access to some of the 3rd party
plugins very difficult so we recommend
downloading this first and getting your
plugins.
http://qgis.org/downloads

38. Data = Shapefiles
• Like most GIS software, QGIS
organizes its data along raster and
vector layers.
• These layers can also be referred to as
Shapefiles.
• Shapefiles can either be created by the
user or found on Online Spatial Data
Repositories

39. Online Spatial Data
Repositories
• DIVA – Free Spatial Data (Solid source of
administrative boundaries, rails, roads &
inland water)
– http://www.diva-gis.org/gdata
• CloudMade – Downloads (Excellent open
source repository)
– http://downloads.cloudmade.com

40. Essential Plug-ins
• Open Streets Plug-in: Allows you to
directly download Open Streets Map data
(Vector and Raster) to QGIS
• Open Layers: Allows you to view Google,
Yahoo and OSM map in QGIS (Raster
only)
• Add Delimited Text Layer: Allow for easy
importing of a GIS-data-containing
spreadsheet

41. To begin we need to install
basic software:
1. QGIS
You want WROCLAW, version,
1.7.3 available here:
http://qgis.org/downloads/
2. LibreOffice
http://www.libreoffice.org/download/
This program is required to add our data to existing spatial
data

42. How to Add Plug-ins

43. In order to add plug-ins
first click on the “Plugins”
Dropdown menu

44. In order to add plug-ins
click “Fetch Python
Plugins..”, highlight in the
Installer window, and click
“Install Plugin”

46. Optional depends on your web
access/connection

47. In order to add plug-ins
click “Fetch Python
Plugins”, highlight open
streets and open layers in
the Installer window, and
click “Install Plugin”
The installed plugin will
then be available in the
same drop-down menu

48. Once installed, the plug-in
will be available either on
the dropdown menu or on
the plugin Palette below

49. Now that our plug-ins are downloaded, we
need to enable them. Click on “Manage
Plugins…” in the Plugins drop-down menu

50. Make sure that the plugins you
want to use are checked. For our
purposes, check “Add Delimited
Text Layer”, “Open Layers” and
“Open Streets Plug-in”
Click “OK”

51. Exploring the Interface
• QGIS is very simple to navigate. It's
made up of a layout area where the
map is drawn surrounded by a toolbar,
layers panel and a status bar.

52. Len De Groot, UC Berkeley School of Journalism QGIS basics for journalists
http://multimedia.journalism.berkeley.edu/tutorials/qgis-basics-journalists/

53. Toolbars
• Toolbars can be controlled and turned
off or on in the Toolbars menu.
• Can arrange them by clicking and
dragging.
• Can configure the toolbars to your liking
(suggestion: aligning them so you have
only two rows of them at the top of the
screen and all buttons are visible)

54. QGIS has many
toolbars, but they are
grouped for easy
identification

55. Now you explore!
• Plug ins
• Toolbars
• General interface

56. Loading Pre-existing
Shapefiles: Vectors

57. Download shapefiles: Diva

58. Choose administrative areas
Note the definitions of the layers are
down below the pull down menu

59. Click “ok”

60. Map pops up on next page:
bottom of page - hit download

61. Drag the files to new folder:
zambia shapefiles

62. Loading Pre-existing
Shapefiles: Vectors

63. Click add Vector Layer to
add shapefile.

64. Once the “Add Vector
Layer” dialog is open, click
browse.

65. Highlight all .shp files & “open”

66. And again click “open”
You will see the directory
and the file name of the
shapefile you chose in the
“Source” dialog box.

67. Now you see Zambia!
Notice that the layer
appears in the map
and the layer
window.
As mentioned before,
vector layers can either be
points, lines, or areas.
This is an area layer

68. Click through the diff layers
It is quite easy to change these
boundaries with one click. Note how
the previous layer 2 disappears and
now we see layer one.
Note how the boundary levels change
with the #s. 2 is “district” boundaries,
1 is province and 0 is…?

69. You can also
simply move the
layer up – the
layer at the top is
the one that
shows in the
screen

70. Notice that we have just added a
point-type vector layer. By the end
of the course you will take raw
health facility data convert it into a
shapefile and be able to place it in
into existing map layers like this!

71. End session one:
THANK YOU!