Welcome to Introduction to GIS Software: QGIS, Class 3
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Introduction to GIS Software: QGIS
(review)
what is a datum?
what is a projection?
name the projection
Lexi
James
Ori
Karen
when does the projection matter?
display
when calculating distance
when calculating area
when you need features to overlap
Finding data
data is often imperfect
hopefully its creator at least documents it
metadata
metadata
"data about data"
metadata can help you understand what a dataset contains
metadata might include:
- data quality
- data organization
- projection / coordinate reference system
cont'd:
- details about attributes
- how recent the data is
- contact organization / person
thematic maps
thematic maps focus on a theme or subject
vs reference maps
Qualitative vs Quantitative
qualitative thematic maps use features' qualities
quantitative thematic maps use features' numeric qualities
this is a quantitative thematic map
source
making a thematic map requires selecting data relevant to your theme
...and layering this data on other, base data
you usually want to select certain features from your layer
there are a few ways to do this
first, we're going to talk about layer filters
column filtering
select by expression
expressions
selecting data and saving as a new layer is another way to isolate data
advanced styling
hiding data with expressions