Understanding the patterns and trends for real estate valuations is important for: city planning, identifying demographic imbalances and in revealing investment opportunities. Visualizing this data in maps provides accessible insights that are otherwise difficult to gain.

The following map animation shows the changes over 4 year periods (2001-2016):

valchg

 

This interactive map let’s you explore the most current values in detail:

 

Data Processing

The data behind the above visualizations is derived from the County of Los Angeles Data Portal – Assessor Parcels Data. This dataset contains a set of attribute fields for each of the 1.1 million parcels and year.

In order to make the most accurate estimate, the “Improvement Value” along with the “Improvement Base Year” fields were used for the selected time period. This is because changes are triggered only by re-appraisable change-of-ownership as established by Proposition 13.

By overlaying a grid (1*1km) and identifying every parcel inside each grid cell by the recorded year (Improvement Base Year), a valuation can be calculated for each area and year. The median value was used so as to exclude outliers.