Mapping
GDES-396 spring 2020 (David Ramos, American University Design)
ramos@american.edu · office hours
This project continues the work that you started in Neighborhoods. Design a map to accompany your text and visualizations.
Work in QGIS, though you should probably move to Illustrator for typography and labels. Create a base map, using data from DC Open Data, OpenStreetMap, or USGS, then add more data or information. For this project, I suggest that you create a reference map that describes a place in broad terms, or a thematic map that depicts key locations.
I would discourage you from trying to show quantitative data using QGIS—that adds another layer of complexity that you don’t need at this early stage. Create visualizations and set them alongside your map, or even overlay them.
Consider scale, choice of projection, what features to show, labeling, and the use of color and line. Ideally, your map will work without a key.
Data sources for the base map
OpenStreetMap
OpenStreetMap is a collaboratively-edited map of the world, with good accuracy and detail. The most usable data format, if you’re starting out, is probably the Geofabrik OSM data extracts. Features are coded; see the list of map Features on the OSM Wiki.
Natural Earth
Natural Earth makes a good source if you’re designing maps of countries or continents.
DC Open Data
DC Open Data is a good source for DC projects. Highlights:
- Street Centerlines
- Wooded Areas 2013
- Waterbodies
- Railroads
- Building footprints
- DC DPR Parks and Recreation Areas
- National Park Service land
- University and College Campuses
- Bicycle Lanes
USGS
If you’re ambitious, you could incorporate data from the USGS via the National Map interface.
Other USGS products:
- National Boundary Dataset — borders of states, counties, and cities (see shapefiles)
Aside about filter syntax
QGIS lets you filter features using SQL syntax. You don’t need to know SQL, though. Here are two examples of simple filters; the text would go into the “Specific filter expression” field of the Query Builder.
Let’s assume you’re working with OSM data via Geofabrik’s extracts. This code would select the roadways that are coded as “cycleway”:
"fclass" = 'cycleway'
And this would select the roadways that are coded as highways or main roads.
"fclass" IN ('motorway','primary','secondary')