Footprint Review Analysis - Footprint Ratio analysis (SOW Task 2.2)

[danrademacher]

Splitting this out from #100

The ratio of gross square footage to footprint area task:

1. From footprints, we'd need to calculate the area in Square Feet.
2. Then join in the reported_gross_floor_area from the data at https://cityenergy-seattle.carto.com/dataset/seattle_buildings_2022_update.
3. Then calculate the ratio reported_gross_floor_area/footprint_area

Us the same data as in this comment https://github.com/GreenInfo-Network/seattle-building-dashboard/issues/100#issuecomment-2153395022

┆Issue is synchronized with this Asana task

[joseph-stout]

on our call in a bit can you point me to the correct dataset to get _reported_gross_floorarea? I am not seeing it in the linked file or anywhere else on carto

[danrademacher]

To get the data we need out of CARTO, we used this query:

SELECT outlines.buildingid, tabular.reported_gross_floor_area
FROM public.data_2022_update as tabular
JOIN public.seattle_building_outlines_2022 as outlines
on outlines.buildingid = tabular.id

Joseph to export that and do the rest in GIS and Excel

That's here https://cityenergy-seattle.carto.com/dataset/seattle_building_outlines_2022 (at least until the query above gets cleared in CARTO)

[joseph-stout]

P:\proj_p_s\Seattle Building Dashboard\2024_update\Reported_Gross_vs_Footprint_Analysis

Pulled down the table with buildingid and reported_gross_area from carto using the query above. Joined to seattle_buildings_2022_update_mr_20240425_v21 file with calculated footprint_area field in square feet. Then created a new field called gross_ratio and calculated as reported_gross_floor_area/footprint_area. Results are in the link to P drive above. Note there are some Null values, but these were present in the source reporte_gross_floor area table as well.

[danrademacher]

Some issues after client review of this table: https://docs.google.com/spreadsheets/d/1-Cer1CH33_t7-SA150D-8x8fVPPalBlY/edit?gid=1863230#gid=1863230

Looks like most of the issues arise out of buildings that are multipolygons with small extra shapes. We need to add up the area of all the polygons in a building and use that as the basis for the ratio

[danrademacher]

Looking at the data, it appears these are polygons and not multipolygons, so we need dissolve based on buildingid

[danrademacher]

Just replace the table in this folder: https://drive.google.com/drive/folders/1WTkAe5bo9G2efz6XXZcFzUVGvXUyP4Om