Pekka Sarkola (Gispo Oy): Understanding and processing geo data with QGIS

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