Workshop . . .

finding questions in and through the data

outline

Intro to spatial methods (10)
- asking questions with John Snow
a look at the data (10)
- from historical document to spreadsheet
- documentation best practices
Palladio (30)
- data exploration and step-by-step tutorial
QGIS (60)
- building a research environment
- managing layers and basic functionality
- georeferencing maps
Other platforms, questions, time to work (10)

WHY

SPATIAL?

the infamous john snow cholera map

no not this jon snow . . .

What was causing the outbreak?

map with just cholera deaths

map with water pumps

gif with deaths and pumps

interviews that helped support the evidence

What can we learn from looking at Louverture's letters?

where

who

when

Is is possible to rethink the Haitian revolution? How it happened? When it happened? Where it happened? Who was involved?

the data

Hand coding letters into a spreadsheet with relevant data: dates, places, people, text, archival location, etc.

So it looks like this:

what are the important fields for working with this spatially

latitude and longitude

but also date, descriptions, people

files we will be using

original
Palladio
QGIS
deletedrows

README:

Important to develop a strategy for documenting and keeping track of changes. Also important to consider how to structure data in order to visualize it.

Palladio

data exploration

data visualization

web based

CSV file or Palladio file format

make maps

make networks

create interactive filters

metadata viewer

http://hdlab.stanford.edu/palladio-app/#/upload

1. making a map

2. filtering with facets and timeline

3. saving a Palladio project

4. showing a personal network

5. showing a map network

6. creating a gallery
7. pulling in a historical map

lets create this

drag your louverture_palladio.csv file into here and then click "Load."

Once your data is loaded in you can provide a name for your project.

You can now preview your data quickly and also make sure it was imported correctly.

Most importantly make sure Machine_date is identified as Date and latlong is identified as Latlong

Click on "Map"

Then click "New layer"

Then click on "Places" and select "latlong"

Then name your map and click on "Add layer"

Go back and click the pencil icon to edit the Map layer.

Then select the Tooltip label and choose a dimension to display. Choose "Recipient."

Click "Apply"

Now your tooltip will display the recipient field.

You can click on the hamburger icon to display or hide layer information

FACETS:

select and unselect recipient to filter points

TIMELINE:

Choose "Machine_date" for date

You can click and drag to create a small bar to signify a date range which can then be dragged across the data to visualize it.

SAVE A PALLADIO PROJECT

downloaded file will be named

"Data export.palladio.1.2.9.json"

rename it to something meaningful.

If yo load this as an existing project you should return to the settings, timeline, facet, etc. when you saved the project

Networks

Load in the CSV file called:

2019-05-02_LouvertureCSV_PalladioNetworks.csv

This file has fields called latlong origin and latlong destination from which we can create a spatial network. In this example we have defaulted all of Louverture's letters to have been sent from Port au Prince.

Create a map and this time select Point to point as the map type. Then select according the source places, target places, and tooltip. Scroll down and then add the layer.

You should have a map showing the origin for all the letters as Port au Prince.

Now click on Graph

It shows the entire network of Louverture and his recipients. To make this more readable and usable we can create a facet using the "machine_date" field.

Gallery

One nice feature of Palladio is that you can browse through every record in a Gallery mode. This feature is especially nice if you have unique image urls. The PalladioNetworks.csv file has an extra field called image_link that has a url to an image of Louverture from New York Public Library. This is just an example for displaying the Gallery.

HISTORICAL MAP

Palladio lets you add a historical map as long as it is already hosted elsewhere, for example, at NYPL or through the David Rumsey Map Libray at Stanford.

Return to the Map Layers and add a new layer. Select "Tiles." And then just Custom Tiles.

Copy and past the URL from the box below into the "Tileset URL" field. Click "Add layer."

https://maps.georeferencer.com/georeferences/988586362611/2018-11-19T00:08:34.285788Z/map/{z}/{x}/{y}.png?key=JxtmprkSqEOUFYPdH9Ga

initial observations with Palladio

One of the first things you will notice is that some of the points have incorrect latitude and longitude.

Palladio quickly reveals these type of errors and you can go back to your CSV and fix them.

Here is another example.

What is wrong with this picture?

Create a facet using Recipient to easily see who received the most letters.

Notice 243 records have no recipient!

what did we do with our observations?

limitations and transition to QGIS

Palladio Resources:

Bullet One
Bullet Two
Bullet Three

manage multiple layers

georeference and use historical maps

show routes

create custom polygons

create a research environment for analysis and exploration

QGIS

1. basic set-up

2. add a CSV

3. style your points

4. add historical maps

5. add another CSV

6. add administrative boundaries
6. save and manage a project

Points color coded by recipient and labeled with a historical map overlay.

Before we begin. Make sure to have the Louverture Spatial Workshop folder on your desktop.

You will be working within this folder so it is helpful to have it in easy to locate place. Once a project is saved QGIS refers back to that folder location.