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Incorporating Charts into Map Apps. Brandon Flessner GIS Developer OKI Regional Council of Governments. Ohio GIS Conference. September 24 – 26, 2018. Hyatt Regency Columbus. Columbus, Ohio. Why Charts?. Why Charts?. July 2018 Unemployment Rate. Source: Bureau of Labor Statistics.
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Incorporating Charts into Map Apps Brandon Flessner GIS Developer OKI Regional Council of Governments Ohio GIS Conference September 24 – 26, 2018 Hyatt Regency Columbus Columbus, Ohio
Why Charts? July 2018 Unemployment Rate Source: Bureau of Labor Statistics
Why Charts? Source: Bureau of Labor Statistics
Why Charts? • Summarize data in ways maps cannot • Provide additional context • Add interactivity • Tell a better story
Use Cases • Summarize map data • Category comparisons (bar chart) • Change over time (area/line chart) • Frequency (histogram) • Correlations (scatter plot) • Popups – give more info on a specific feature • Filtering/Highlighting
Getting Started • COTS vs. Custom • Charting Libraries • Querying and Performance
COTS vs. Custom COTS • Cheaper • Very quick deployment • Support • May not be customizable • Unneeded additional features • Custom • Full control over application • Larger time and financial investment • Need for in house support/staff
Charting Libraries • D3.js • Google Charts • ChartJS • Many more https://github.com/d3/d3/wiki/Gallery
ESRI Cedar • https://esri.github.io/cedar/ • Plugs into your ArcGIS Map/Feature Service • Handles querying the service and structuring the data for chart consumption
Querying and Performance • How best to get data from server to client? • Load all data up front? • As needed? • Hybrid approach • How is you map already loading data? • Feature layer vs. map image layer • How best to structure the query? • outStatistics • groupByFieldsForStatistics • orderByFields
Do Don’t Keep it simple Use map colors (chart as legend?) Order bar charts (by frequency descending or time) 3d charts Pie chart with 10+ categories (all others category?)
Questions?See more at oki.org/mapsapps Brandon Flessner bflessner@oki.org