Welcome to Introduction to GIS Software: QGIS, Class 12
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Introduction to GIS Software: QGIS
what is georeferencing ?
what is nice about Landsat ?
2007: all Landsat imagery becomes free
what does it mean to say aerial imagery has 30m resolution ?
(2010, Deepwater Horizon)
source
FAA and Coast Guard enforced a media blackout
So aerial imagery could not be collected with airplanes
"We're going to make our own aerial pictures of this oil sheen as it's approaching our island. We're going to get images of what our wetlands look like before they got covered in oil."
source
"While mapping the oil spill, we were not trying to duplicate the satellite or flyover imagery..."
"...we were helping Gulf Coast residents to use balloons, kites, and other simple and inexpensive tools to produce their own documentation of the disaster."
source
"Gowanus sewage scum is typically made up of ground up styrofoam particles, ...
source
... to which sewage bacterias, restaurant grease and algae then attach themselves"
source
open data
open data
data that is:
accessible (online, in a widely-used format)
open data
data that is:
accessible (online, in a widely-used format)
licensed freely
open data
data that is:
accessible (online, in a widely-used format)
licensed freely
usually created by a large entity
collaborative data
what is OpenStreetMap (OSM)?
a website?
a map?
data on a server somewhere?
a community?
"the free wiki map of the world"
VIDEO
started in 2004 in the UK
started in 2004 in the UK
first State of the Map conference in 2007
started in 2004 in the UK
first State of the Map conference in 2007
over 1 million registered users in 2013
license
license
Open Database License (ODbL)
essentially an open source license, but for data
source
what does the data look like?
shapes
nodes (points)
ways (lines)
closed ways (polygons)
nodes, ways, closed ways
are just shapes with no meaning until you give them attributes, as in any GIS
so you have to add attributes
an attribute table wouldn't work because:
there would be thousands of columns
an attribute table wouldn't work because:
there would be thousands of columns
and most of those columns would be empty (eg 'electrified')
an attribute table wouldn't work because:
there would be thousands of columns
and most of those columns would be empty (eg 'electrified')
what you could map would be predetermined
tags
name=Union Square West
tags
we make them up as we go.
tags
we make them up as we go. really.
folksonomy
folksonomy
a collaborative system of categorization
you can tag things any way you want
how do you use the data?
export
export
we'll use a QGIS plugin for this