Welcome to Introduction to GIS Software: QGIS, Class 2

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Introduction to GIS Software: QGIS

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what is open data?

Cartographic design & conventions

think about:

scale

hierarchy

"Important things must look important, and the most important thing should look the most important."

Understanding Different Geographies

color

Think about what the colors you are using mean to the viewer.

Use contrast to your advantage.

symbology

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hierarchy

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color

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Color Brewer

positioning

the "island effect"

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what you include is significant

what you include is significant...or will be interpreted as significant

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same with what you exclude

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in-class excercise, part 1

Projections and coordinate systems

latitude and longitude are always in relation to a datum

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mapschool.io

a datum is the combination of a spheroid and how it's being used

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you will often see NAD83 and WGS84

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projections mainly distort

mercator puzzle
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every projection distorts some aspect of the geography

you have to pick the one(s) that make the most sense for what you're doing

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best for New York area, many city datasets use this

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projections are just math

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luckily GISs are pretty good at math

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in-class excercise, part 2

more about shapefiles

shapefiles are difficult to read

(without proper software) shapefiles are difficult to read

1. column names limited to ten characters

how do you pronounce "C_DIG2DESC"?

2. multiple files make up a shapefile

3. one geometry type per shapefile

despite it all, shapefiles are still by far the most common spatial data format

CSVs are handy for point data

these are simply text files

comma separated values

handling projections in QGIS

usually you will pick a projection for your project to make your data look good

to do this, change your project's projection

sometimes you need to change the projection of a layer to do calculations

to do this, you must save the layer with the new projection

don't change a layer's projection without saving as a new layer

in-class excercise, part 3

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design choices

Is it effective?

Does it follow cartographic principles?

How could it be improved?

data

Are data sources listed?

If the data was modified, is this described?

point of view

Does the map make a statement?

Could it make the statement more effectively?