1. Understanding
and
processing
geodata
with
Quantum
GIS
Pekka
Sarkola
Gispo
Oy

2. Gispo
Oy
We
help
customers
to
take
advantage
of
the
FOSS4G
(Free
and
Open
Source
So;ware
for
Geospa=al)
so;ware
and
open
data.
We
support
the
development
and
u=lisa=on
of
open
source
so;ware
and
open
data.

3. GIS
in
5
minutes
GIS
=
Geographic
Informa?on
System

4. Data
representa?on
• Representa?on
of
real
objects
• Abstrac?on
to
– Discrete
objects,
like
house
– Con?nuous
fields,
like
rainfall
amount
or
eleva?on
• ”60-­‐80%
of
all
informa=on
has
loca=on”
• Can
only
physical,
real
objects
has
loca?on?
– Email
– Money
in
bank
account

5. Geographic
informa?on
data
• Raster
– Image
• Vector
– Point
+
ANributes:
– Polyline
name,
id,
type…
– Polygon

6. Collect
Share
Model
Visualise
Analyse

7. What’s
not
GIS?
• CAD
– Computer-­‐aided
Drawning
– Be
aware
about:
DXF,
DWG,
…
• Google
Maps
– Points-­‐on-­‐the-­‐map

11. Map
projec?ons
• Always
distor?on
of
– Area
– Shape
– Direc?on
– Bearing
– Distance
– Scale

12. Coordinate
systems
• You
use
already
defined
coordinate
systems
– …or
do
your
own
coordinate
system
• Roughly
2000
–
3000
different
coordinate
systems
• Web
Nerd
Shortcut
(WNS):
– ”I
just
use
GPS
coordinates”
• GIS
Expert
Answer
(GEA):
– ”So,
you
will
use
WGS84.
Like
La?tude
/
Longitude.
How
do
you
calculate
distance
between
two
points?”

13. Map
Projec?on
• WNS:
”I
will
use
Google
Web
Mercator
on
my
data
visualisa?on”
• GEA:
”Right:”

14. Geodata
File
formats

15. Geodata
File
Formats
• WMS:
”I
will
use
SVG/XML/KML
in
my
app…”
• GEA:
”As
you
want,
but…”
– Size
of
files:
XML
is
preNy
big
– Features:
KML
includes
presenta?on
– Data
inside
SVG?

16. Using
Quantum
GIS

17. Why
Quantum
GIS?
• Some?mes
you
have
to:
– View,
analyze,
convert,
manipulate
or
do
something
else
with
your
geodata
• Quantum
GIS
is
easy
to
use,
free
open
source
sojware
for
Linux,
Mac
and
Windows
plakorms
• More
info
and
download:
– hNp://www.qgis.org/

18. Live-­‐demo

19. Where
I
can
learn
more?
• Open
Knowledge
Fes?val,
17.-­‐22.9.2012
– Open
Geodata
Hackathon
and
all
other
Open
*
things
– www.okfes?val.org
• Paikka?etomarkkinat,
6.-­‐7.11.2012
– Annual
GIS
event
in
Finland
– www.paikka?etomarkkinat.fi

20. Or
just
contact
me!
Ques%ons?
Thank
you!
posiki
Presenta?on
includes
maps
from:
©
Na?onal
Land
Survey
of
Finland,
data
extract
05/2012