QGIS training class 1

Copyright (C) 2013 microbase.LLC All Rights Reserved.
Geographic
Information System
QGIS Introduction(1)
microbase.LLC
http://microgeodata.com/

Agenda
1st
2nd
3rd
What’s QGIS?
Basic usage
Basic data management
Spatial data handling
Spatial Analysis
Geocording
Create Vector data
About coordi nate system
Create KML data
Utilize OSM data

Contents Today
1st session
1 What’s QGIS?
2 Basic usage
3 Basic data management
4 Map design
Homework

What’s Quantum GIS (QGIS)?
• One of open source GIS software named FOSS4G
(Free and Open Source Software for Geospatial)
• a user friendly GUI
• Multi-platform（Win, Mac OS X, Linux）
• Multi-language
• Rich functions for a function enhancement

What QGIS can do?
Create and edit
GIS data
Display GIS
data
(overlay, thematic
map...)
Select / Join data GIS data analysis

Basic usage

2.1 Launch QGIS
• Double click the QGIS shortcut
icon on desktop
• The window will open.

QGIS window will open like below.

toolbar
menu
map viewLayer
map info / settings
topmenu

Install Plugin
• Choose “Fetch Python Plugins...” from “Plugins” on the top menu and
search “Table Manager” from Filter form in “Plugins” tab.
• “Table Manager” is a database management tool.
• Choose and install “Table Manager”.
• When installing plugin, internet environment is necessary.

• Choose “Manage Plugins...” from “Plugins” on the top menu and
click the “Add DelimitedText Layer”.
• “Add DelimitedText Layer” function is used for importing CSV format data.
• Checked function will be visible on the main menu and able to be used.
“Add Delimited Text
Layer” will be visible.
Plugin Management

2.2 Add data
GIS data can be devided into 2 types..
• Raster type ex) JPEG, PNG,TIFF
• Vector type ex) Shape ﬁle(.shp)
For instance, imagine a river and bridge,
Raster type
aggregate of colored
dots
Vector type
line data connecting
starting points and
end points

Exercise data
lecture1_data
tokyo23
homework1

About Shape file
• Vector type data mostly used in the world.
• Available in most GIS softwares.
• “Shape file” format is composed of more than 3 files as follows.
*.shp (geometry type and geographical coordinates)
*.dbf (attributes of features such as name and figure)
*.shx (relationship between shp and dbf)
*.prj (the coordinate system and projection info)
Shape file
same file name
These files must be
put in same folder.

NAME AREA PERIMETER
0
1
2
3
4
5
AAA 18352 644
BBB 22496 756
CCC 22050 602
DDD 7548 352
EEE NA NA
FFF NA NA
*.shp *.dbf*.shx
CCC
AAA
DDD
BBB
Point Data ex) amedas data, shop data
Line Data ex) road data, railway data, river data
Polygon Data ex) city shape, building data
<Feature type>

1) Click “Add vector layer”
2) Browse ﬁle
3) Open
Add “ku.shp” in “tokyo23” folder.

※ Caution ※
• Japanese GIS data by Government such as National Land
Numerical Information and census data tend to be recorded in
Shift-JIS. If you use Mac OS or Unix, Check that the encoding is
Shift-JIS before adding the data.
• Shift-JIS can be converted to UTF-8 later.

Tokyo special districts are displayed.

Display a feature
1) Click “Identify Feature”
2) Click a feature

Shibuya info can be shown in a new window.

1) Click “Save Project”
(Ctrl + S or Command + S）
2)You can save it any name in any folder.
3) save a project as “.qgs” type
2.3 Save a project

Exercise1
Add following data in the folder “tokyo23”.
subway.shp (Line data: a subway in Tokyo Special district)
station.shp (Point data: a station in Tokyo Special district)
convenience.shp (Point data: a convenience store in Tokyo
Special district)
elevation.shp (Polygon data: an terrain data in Tokyo special
district)

Hint
You can select plural ﬁles while pushing
Ctrl key ( or Command key).

Answer

The order of layer on TOC can be
altered by drag and drop.
Front
Back
2.4 Change an order of each layer

A layer can be hidden without checking a check
box of layer.
Only subway and station layer
can be seen on map view.

Delete a layer
Delete other than “ku” layer.
#This function doesn’t delete a ﬁle
itself in the ﬁle directories.

Basic data management

What’s an “attribute”?
NAME AREA PERIMETER
0
1
2
3
4
5
A棟 18352 644
B棟 22496 756
中庭 22050 602
生協購買 7548 352
ポスト NA NA
道路 NA NA
中庭
A棟
生協購買
B棟
・ポスト
attribute table
“Attribute” means an property of each feature such as a name and an
area. In case a shape ﬁle is used, the attribute is saved into a dbf ﬁle and
can be edited.
The feature “0” has a name of “A building” and an area of
18,352 square meters, perimeter of 644 meters.

Open Attribute table
See an attribute table of “ku” layer.
• Add “ku.shp” on layer and open its attribute table.
ﬁeld
Each line
links to
vecoter on
map.
Click “ku” layer on the right
mouse and choose “Open
Attribute Table”.

If you choose a line from attributes, the
linked map feature also be chosen.
If you choose a map feature on map view,
the linked line also be chosen in the similar
way.
click a line number which
you’d like to choose.
Choose “Select Single
Feature” and click a map
feature on map view.

Select layer by attribute
Select a city which has more than 20 km2 in area from attribute table.
About ﬁelds
• KU : city id
• NAME : city name
• PERIMETER [ m]
• AREA [m2]
1) Click “Advanced Search”.

Input a condition expression on “SQL where clause”.
If you click, item will be
added to “SQL where
clause”.
“Test” show you whether the condition expression is
correct or not, and the number of matched features
Input “AREA >= 20,000,000”
( m2 -> km2 )

12 cities are selected.
Deselect

Select features under plural conditions
AND and OR enable to select features under plural conditions.
case1: ku which has more than 10 km2 and less than 20km2 in area
AREA >= 10000000 AND AREA < 20000000
AREA < 10000000 OR AREA >= 20000000
Also, NOT is useful when you’d like to select features under
opposite conditions.
case3: ku which doesn’t have not less than 20km2
NOT AREA < 20000000
case2: ku which has less than 10 km2 or more than 20 km2

Exercise 2
1) Select city features which has more than 50km in “PERIMETER” and
doesn’t have less than 50km2 in “AREA”
2) Save the selected features as “large_wards.shp” in “tokyo23” folder.
3) Open “large_wards.shp” in QGIS

Answer
PERIMETER >= 50000 AND NOT AREA < 50000000

Join table
“Join table” is to combine different table based on a key ﬁeld in
common.
This function is very useful when you combine GIS data with others or
external data such as csv and dbf data.
NAME AREA
0
1
2
Hokkaido 83456.38
Aomori 8918.45
Iwate 15278.85
PREF POP
0
1
2
Hokkaido 5506419
Aomori 1373339
Iwate 1330147
NAME AREA PREF POP
0
1
2
Hokkaido 83456.38 Hokkaido 5506419
Aomori 8918.45 Aomori 1373339
Iwate 15278.85 Iwate 1330147
name, area name,population
add pop ﬁeld into the target
table based on the
prefecture name.

The column “pop” has population data inTokyo in 2010.
Load “ku_pop.csv” in “tokyo23” into QGIS.
“Layer” > “add vector” > import csv

CSV data has been added.

Join population data inTokyo special districts into “ku” layer.
Choose a “join” tab above menu of the layer property “ku” layer
csv layer
Use city name as a key ﬁeld
shp csv

You can join / unjoin other data more.
“ku_pop” layer is joined to “ku” layer.

“ku_pop” attributes has been joined.
Attributes of “ku” Attributes of “ku_pop”

Decide where one
wants to save the ﬁles.
Save the joined layer as “ku_pop.shp” in “tokyo23”.

Open “ku_pop.shp” and check that the attribute table is joined one or not.

Calculate field
“Calculate field” enable to handle field values at once.
Calculate a population density in each area using “pop” and “AREA” fields
in the attribute of “ku”.
Population density = Population / Area [pop / km2]

Toggle edit mode
Toggle edit mode before
calculate ﬁeld.

Click “calculate field”.
Calculate field
“pop” field is loaded
as string. the field in
CSV are all regarded
as string.
Caution:
“calculate field can’t
be conducted
when string and
figure data coexist
together.

to int ( ) = ( ) 内のフィールド値を整数に変換
Fill as above

Joined!!

Map Design

Exercise1
Add following data in the folder “tokyo23”.
subway.shp (Line data: a subway in Tokyo Special district)
station.shp (Point data: a station in Tokyo Special district)
convenience.shp (Point data: a convenience store in Tokyo
Special district)
elevation.shp (Polygon data: an terrain data in Tokyo special
district)
Again

Change point styles
Click “Property” on the right mouse
button station(or double click the layer).

Open the window “layer proper ty” and
choose “style” tab.

“Symbol proper ties” window will open.
1) Change symbol layer type to “SVG marker”
2) Choose a mark of “train” from the image list.

The station symbol has changed.

Uncheck the check box other than
“elevation” layer and open its
properties(or double click the layer).
Change polygon styles

Change a color of “elevation layer”
according to elevation value.
Low High
Generally, higher area colors
warm color(ex.red,yellow).
Lower area colors cold
color(ex. blue,green).

1) Choose “Graduated”. 2) Choose a column “ELEV” which has elevation value.
3) Choose any color ramp.An
original color ramp can be made.
4) Choose a number
of classed and a
classiﬁcation mode.
5) Finally, click “Classify”.Then the classiﬁcation
result will be displayed above.
If you’d like to arrange your way, just click
“Symbol color”,“Range” and “Label”.

Result

Change par tial symbol styles
show different markers depending on attributes.

1) Choose “Graduated”.
2) Choose and double click a rule row
which you’d like to change.Then the rule
property will open.
(Default setting has no rule)

4) Input “CNAME LIKE ‘Circle%’ on
“Expression” form.
(or “CNAME = “circleK”)
‘LIKE’ : partial matching
‘=‘ : perfect matching
3)Input any name in “Label” form.
Click “...” next to “Filter” form.
5) Marker type can be chosen
as mentioned before.
A ﬁlter rule can be input from
“Expression string builder”.

Existing rule has been edited.
If you’d like to add an another rule or delete

Only “CircleK” has been displayed.

Display a label
1) Choose “Label” tab from tab menu in Properties “ku”
2) check the checkbox
of “Display labels”.
3) Choose “NAME” in “Field
containing label” form.

The name of “ku” has been displayed as a
label on the polygon data.

Exercise 2
1) Delete the label “ku”.
2) Add pop.shp(population on street scale).
3) Classify poplation in 1995(“P1995”) into 4 categories as follows.
class 1 : 0 ∼ 1000 (blue)
class 2 : 1001 ∼ 2500 (green)
class 3 : 2501 ∼ 5000 (yellow)
class 4 : 5001 ∼ (red)

Hint

Map Expor t
Export your map an imagery ﬁle for printing. QGIS has an additional
function such as adding a direction symbol and a scale bar for printing.
Click “New print composer” icon from toolbars.
Add a map, symbols and others to
Initial screen from the menu.

1) Click “Add new map” icon
Add a map into composer screen
2) Drag at any place on the composer
screen while choosing “Add new map” icon
map size and other settings
can be adjusted freely.

Those elements can be
modiﬁed from “Item
Properties” at the right side
Add icon and
pictures.
Add Label
Add legend
Export as an
imagery, PDF, SVG.

Contents Today
1st session
1 What’s QGIS?
2 Basic usage
3 Basic data management
4 Map Design

HOMEWORK

DATA
homework1
pref_pop.csv
Japan_pref.shp

(1) Add Japan_pref.shp and pref_pop.csv on layer.
(2) Join Japan_pref layer with pref_pop and save it as
Japan_pref_new.shp .
(3) Calculate population density in all prefecture using both
pop2010 and pop2035 ﬁeld.
(4) Classify the poplation density in 2010 and 2035 into 5
categories.

QGIS training class 1

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