Maps on the internet

The DFW Election Dot Map

Web pages: client/server architecture

• Web server hosts and serves sites and data to be consumed by web clients (e.g. your browser)

Source: Fu and Sun (2011)

Tiled mapping

• To speed browsing, web maps often display map images as “tiles”
• Tiles are defined by their zoom level and coordinates
• Common coordinate system: Web Mercator

How tiled mapping systems work

Source: Bing Maps

CARTO

• Spatial database in the cloud
• ‘Freemium’ service; free to get started, more storage costs more money
• Powerful interface for running queries, visualizing your data; dashboard capabilities
• Link: http://www.carto.com

Loading data into CARTO

What makes a good web map?

• Brian Timoney: maps should be fast, intuitive, informative, and fast!
• This can be accomplished through generalization, scalability, and minimalism

Generalization

• Important to consider purpose of your map when selecting resolution of your data

Generalization

• At small scales, lots of detail can be unnecessary and computationally burdensome
• Large feature services can be very slow in web maps

• When building applications, ask yourself: how much detail do I need?

• In ArcGIS: look for the “Generalization” toolset in the “Cartography” toolbox

Scalability

Example: NPR Census Map

Minimalism (when appropriate)

Minimalist solution

Styling data in CARTO

CARTO widgets

Wrap-up discussion