What is geo data and how to get the most from it

james.milner@geovation.uk

@JamesLMilner

loxodrome.io

James Milner

Enough about me

Positioning & location sharing has become an indispensable part of modern life

What do we mean by location?

That bar behind the coffee shop on Westferry Road?

An address?

A postcode?

A latitude and longitude?

Easting and Northing?

x and y?

Lets call this 'geo data'

Many providers build up lots of geo data into products or assets

460+ million geographic features in the database
- 29,105,155 residential addresses
- 2681 Roads named High Street
10,000 changes a day to the master map of Great Britain
16 full coverage UK level, maintained, open data sets

Data at the Ordnance Survey

How do we locate things precisely?

Coordinate Systems

Textual data may be useful in context, but it is not directly plottable on a map

How do we model geographical data?

Points: a house, a shop, a postbox, etc

Lines : Roads, Rivers, Paths etc

Polygons: fields, parks, lakes etc

Raster to Vector

Storing and Retrieving Data

Flat Files

Shapefile

Tabfile

CSV

KML

GML

etc

Databases also play a key role

 SELECT ST_Area(the_geog)/POWER(0.3048,2) 
        As sqft, ST_Area(the_geog) As sqm FROM somegeogtable;

Spatial Querying

What about serving out data?

OGC Standard Services

Also increasingly we serve and query this data via de facto APIs

Andreesen Horowitz (2014)

Alongside this ~30% have access to GPS. This ignores cellphone triangulation, WiFi etc

Pew Research (2012)

We can conservatively estimate 20% of the world will be able to consume and produce geo data by 2020

That's ignoring machine produced data

Cell phone networks can produce ~100'000 geo events per second

To put that into perspective, there are around ~6000 Tweets per second globally

Source: Open Signal 2015

OK, so you've got all this data, now what?

Processing

Actually processing data to a useful state can take up a lot of time

Mobile and Web Viewing

What are your mapping framework options?

Hello Map

// ArcGIS JavaScript API
require(["esri/map", "dojo/domReady!"], function(Map) {
  var map = new Map("map", {
    center: [-118, 34.5],
    zoom: 8,
    basemap: "topo"
  });
});

// Google Maps JavaScript API
var map;
function initMap() {
    map = new google.maps.Map(document.getElementById('map'), {
      center: {lat: -34.397, lng: 150.644},
      zoom: 8
    });
}

// Leaflet JS
var map = L.map('map').setView([51.505, -0.09], 13);
var attr = '© <a href="http://osm.org/copyright">OpenStreetMap</a> contributors';

L.tileLayer('http://{s}.tile.osm.org/{z}/{x}/{y}.png', {
    attribution: attr
}).addTo(map);