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Urban Start-up Agglomeration and Venture Capital Investment (view source)
Revision as of 18:59, 18 September 2019
, 18:59, 18 September 2019→Other
Note that The Sears Building Area wasn't in the Midtown TIF when they did the last bond issue in 2015 (see map on A-1 [https://midtownhouston.com/wp-content/uploads/2015/04/Midtown-Redevelopment-Authority-TX-Tax-Increment-Contract-Rev-Ref-Bonds....pdf]). They raised $13.5m in 2015 to pay off existing debt, and then raised $39.31m in 2017 [https://midtownhouston.com/wp-content/uploads/2017/04/Midtown-Redevelopment-Authority-TX-Tax-Increment-Contract-Rev-Ref-Bonds-Srs-2017-OS.pdf] to conduct the Plan, pay off debt, etc. The area was in the map in the 2017 issue. The area around the Sears building "contains virtually no taxable property and therefore will produce no significant Captured Appraised Value".
==Density Maps==
It's useful to lay each year's chosen hulls on top of each other over time (from say 1995 to present, or using the layer with the max number of hulls if the year never achieves the chosen hull count). However, to do this we should expand the hulls, because all hulls have points at their corners and most hulls have points only at their corners. I propose using ST_Expand to increase X and Y distances separately. The method would be to take ((Centroid's X-ST_XMin)+(ST_Xmax-Centroid's X)/2) as the X expansion distance and likewise for Y.
Visually, it is easy to layer the years, using opacity to build up an effect over time. In the data, it is more difficult. Each year could have thickness one and then we could count the number using ST_intersects while creating the new hulls using ST_Intersection (returns null when no interection). If there are more than one intersections with the highest intersects count, then we could take the largest one as the ultimate one. The centroid of the ultimate intersection would be the heart of a city's startup scene.
One problem with this method is that there are partial intersections. We could use ST_Difference to return the part that doesn't intersect... a bigger problem is that we are restricted to pairs of geometries. Using a cross product we could test all rows against all other rows. But then we'd need to aggregate the intersections... One method is to use a recursive CTE [https://gis.stackexchange.com/questions/269875/aggregate-version-of-st-intersection]. ST_Union is truly an aggregate function but not what we want in this context.
Another thing that might be an issue is that when hulls are expanded, they may intersect within a year too. Counting across year and within year intersections the same would simplify this, but it might be important to track them separately?
==Other==
