We’ve had surmountable technical challenges during the development of the National Broadband Map, we’ve dealt with the challenges, solved technical problems and hope that others can take advantage of what we have created. The problems we have solved will help others, we’ve done some heavy lifting work so others don’t have to and we’ve made those solutions available via our open source licensing of the application.
The open source licensing of all of our development means that others whether inside or outside of government can take advantage of what we have developed for whatever use they see fit.
In summary, some of the functionality that we have made available on an open source basis:
Taking Standard File Formats
The inputs to the application are standard Shapefiles a common GIS format, that often requires specialist software to read. By taking the Shapefile format we can take outputs from standard GIS packages and display them over the Google Maps base. This means we can display legacy data in new and interesting ways.
Generation of transparent map tiles to display complex geometries using Google Maps
We have had to deal with very complex files to display on the map, most notably for wireless network coverage, trying to visualise the coverage completely within the browser is impractical. We generate transparent image files which are then overlaid across of Google Maps. Using XML based technologies to do this would be impractical.
Pre-Rendering and Caching of Map Tiles
It takes a long time to draw a map tile, so to improve the user experience we have a render queue, this means the tiles are rendered on our server and cached on our hard disk. The rendering takes advantage of any idle processor time, meaning we are improving the user experience without degrading it. Prior to this functionality the map tiles were rendered on demand which was degrading the user experience.
Server Side Clustering
Displaying a few points of data on a map is trivial but to represent tens of thousands of points gets tricky. We use server side clustering techniques to give a visual representation of the density of those points. The markers size represents the density of the cluster.
Bulk Geocoding
We have the ability to upload address data to the application and have it geocoded with a latitude and longitude. This means we can turn thousands if addresses into properly geocoded points at once, and programatically.
RESTful and SOAP Interfaces
These interfaces let us expose data held within our database via different interfaces and in different formats, it also allows others to write directly to the database. The interfaces have a security model so we can give different users, different levels of access and assign ownership of different demand points to different users.
Accessible Access to Map Data
Maps by their nature are visual, yet we have functionality for geographic data, specifically our demand points to be accessed and browsed in a text based fashion.
If you want more information on how to browse the code base or install the entire application then it’s on our website.
http://broadbandmap.govt.nz/source-code/
One Comment
This is all good helpful stuff.
Can you also provide the resultant map (not just the data points)in say a WMS form so that Councils can load it into their GIS and compare / overlay against their data to help expidite decision making?
(Yes, I know they always want something else!)
Jim McLeod