Building a Real-Time GIS Services Workflow

Brent Porter

Center for Space Research

bporter@csr.utexas.edu

Experience

• Web-based GIS

• Desktop/os-level Applications/Scripts

• GIS Infrastructure & Architecture

So, I am always torn in these kinds of meetings!

Do I talk about the programming and the lessons learned creating that code?

Let me apologize now if you were looking for the coding option - I think in this venue going through the process is useful.

Today's Outline

• Design of application data

• Example application - MOVES

• Workflow development

Let's discuss real time data...

or really any 'living' GIS mapping application or data flow

Living?

• One that may be different from access point to access point
• In other words, not static
• That is really what we mean we say 'Near Real Time' or 'Real Time' data/application

Which isn't to say...

Much of our discussion will work with static data too....

So.

Back to Design Characteristics. In particular Data design.

• One to a FEW operational layers (data streams)
  • Temporal component that is intrinsic to the value of the data that is being visualized
  • Not too many attributes! (Users don't need to see 50 fields - think 10 as a rule of thumb)
  • Not too many features. This is the web - and now more often than not it is also mobile. Too many features will make your app slow/unstable
  • Not too complex - ask yourself if you need data with large numbers of vertices.

Data Design Continued

• Also you want some common geographic features - something familiar to the users
  • Think of the common mapping patterns online
    • Aerials/Streets
  • Remember who your users are - if they are the public they will not be as familiar as you with your application. Using a common set of features sets them up to succeed.

Operational Layers - examples

• Precipitation accumulation
• Precipitation forecast
• Geotagged photos
• Radar
• River gauges

Base Layer - examples

• Seamless or Patchwork Aerials or Satellite Imagery
• Streets based vector layer(s) - like open streetmap, bing maps, google maps or map quest maps
• Other thematic vector layer(s) - topographic, oceanographic, etc.
• Vector tiles - think Streets map like but YOU get to decide how it looks (colors/weights/etc)

Other Design considerations

• UI/UX
  • mobile first, responsive, native app, etc
  • Bootstrap, SASS/Less
• Application Design
  • collection of pages, single page app, thick client app
• Architecture Design
  • MVC, MVVC, etc

Unfortunately
 each of those could be a separate presentation

Today's Outline

• Design of application data

• Example application - MOVES

• Workflow development

Working Example

• MOVES stands for Modeling, Observations and Visualization for Emergency Support (MOVES) Network
• http://magic.csr.utexas.edu/public/views/

Today's Outline

• Design of application data

• Example application - MOVES

• Workflow development

Putting it all together

Workflow Considerations

• Data - incoming
• Data - storage
• Data - access
• Data - visualization

Data - incoming

• Need to use some tool to gather/process data into formats that can be used to store data
• Java/Python are my two favorite candidates
  • We have expertise with each
  • GIS api availability to allow you to focus on collection rather than creation of functionality
• GDAL/ogr2ogr - http://www.gdal.org/ We use this primarily for the ogr2ogr functionality that dovetails nicely with our data storage solution.

Data - storage

• PostgreSQL
• with PostGIS  installed
• using built in functions to create javascript object notation (JSON) snippets
• https://www.postgresql.org/
• http://postgis.net/
• But... we still do have some data stored on file as well! - for uses such as image tiles in rest endpoint access

Data - access

• Rest endpoints! YMMV on how to implement these but I am currently using Nodejs for most of my rest endpoints - https://nodejs.org/en/
• Also both the pg/pg-connect libraries and restlet library for Nodejs from the npm js repository - https://www.npmjs.com/
• Make sure to emit JSON from the rest end point queries - http://json.org/

Data - visualization

• LeafletJS - http://leafletjs.com/
  • very intuitive, open source javascript library that is easy to begin creating mapping applications with
  • also has many third party plug-ins like ESRI (see next bullet)
• ESRI leaflet plugin - https://github.com/Esri/esri-leaflet
  • allows you to access ArcGIS server tiled maps, feature layers and other ESRI Rest-based technology
• JQuery - http://jquery.com/ - used to integrate your spatial functionality with the common behaviors users need from a web 2.0 application.

URL

https://slides.com/organizedchaos/building-a-gis-services-workflow/

Questions?

email - bporter@csr.utexas.edu

twitter - brentaporter