An Introduction to Web Maps
University Libraries | CRDDS
Who has used a web map today?
Web maps have become ubiquitous...
Let's define "web map"
Not paper!
...Digital...
...but not static.
Interactive!
Viewed in a web browser.
A web map is not:
"GIS on the web"
A web map is:
"Slippy!"
A bit of history.
1996: MapQuest gives us a map over web service
2005: Google gives us the slippy map!
How did that map get so slippy?
Tiles:
A grid of images
20ish zoom levels
Images increase exponentially at larger scale
Anatomy of a web map
Basemap + Feature Layers
Basemap
Basemap + Point Feature
Basemap + Line Features
Basemap + Polygon Features
Data
Basemap:
- Map tiles
- Usually 3rd party, but you can create them from scratch too (but that's another workshop)
Data
Feature Layers
- GeoJSON (ideal web-format)
- Spreadsheet
- Shapefile
- Other geo-formats...
How do I make a web map?
GUI-based options:
- ArcGIS Online
- Carto
Code-based options:
- JavaScript: Leaflet, MapBox, Google
- R: tmap, Leaflet
- Python: Folium