Main Tools
Carto
Published
Online
Publisher
The Bristol Cable
Bristol’s Council House Auctions
I used Carto to quickly map Bristol’s council house auctions over the last 10 years. This helped to better understand where, when, and how many council houses were sold.
Methodology
A colleague obtained through FOIA a list of the addresses and dates corresponding dates of council house auctions in Bristol.
I ran this list through a batch geocoder to obtain the coordinates of the properties.
This new dataset was then uploaded to Carto, where I applied the ‘torque’ temporal mapping feature. The CartoCSS required a bit of tweaking to force the dots to remain after they appeared
/** torque visualization */
Map {
-torque-frame-count:256;
-torque-animation-duration:30;
-torque-time-attribute:"date";
-torque-aggregation-function:"count(cartodb_id)";
-torque-resolution:2;
-torque-data-aggregation:cumulative;
}
#bristol_council_housing_auctions_geocoord_address_{
comp-op: multiply;
marker-fill-opacity: 0.9;
marker-line-color: #FFFFFF;
marker-line-width: 19;
marker-line-opacity: 0.2;
marker-type: ellipse;
marker-width: 5;
marker-fill: #FFCC00;
}
#bristol_council_housing_auctions_geocoord_address_[frame-offset=1] {
marker-width:7;
marker-fill-opacity:0.45;
}
#bristol_council_housing_auctions_geocoord_address_[frame-offset=2] {
marker-width:9;
marker-fill-opacity:0.225;
}
#bristol_council_housing_auctions_geocoord_address_[frame-offset=3] {
marker-width:11;
marker-fill-opacity:0.15;
}I also created a second layer to enable constant hovering over data points, displaying a tooltip containing the date of sale and area. The CartoCSS for that is:
/** simple visualization */
#bristol_council_housing_auctions_geocoord_address_ {
marker-fill-opacity: 0.9;
marker-line-color: #FFF;
marker-line-width: 1;
marker-line-opacity: 1;
marker-placement: point;
marker-type: ellipse;
marker-fill: white;
}