Methods & Analysis
Map 1 - Properties/Current and Future Floodplain
  1. Retrieved property data from Hope (not geo-located and with not practical BBL numbers) and from Ascendant (already geo-located but with projection issues)
  2. Re-coded BBL numbers for both properties from scratch through padding numbers and concatenation
  3. Conversion Tool - Convert Exl into Table
  4. Table join between properties BBL and Mapluto BBLs for Manhattan but 6/100 properties did not join. I figured out that some addresses that I had initially split into two (e.g. 242-244 East 106 Street) should be kept as one because splitting them generates a new BBL code that of course does not exist. After I joined the address back I solved 5 of 6 missing BBL which were not joining.
  5. Selected all null (not joint attributes) and selected inverse to obtain only BBLs in CD 10 and 11, where properties are located. Exported data selection as shapefile.
  6. Created 1 field per floodplain (2015, 2020, 2050) set with a short integer and all values at 0 (NOT IN FLOODLAIN). From the FEMA 2015 I selected by attribute only the 100 year floodplain
  7. Selected by location - from the BBL with condition of intersecting with floodplain 2015, 2020, 2050, 2080. Each time I selected with field calculator BBLs that intersected with each floodplain and I assigned the intersection at 1 (IN FLOODPLAIN)
  8. Created another column where I aggregated all numbers to understand the BBLs that fall in the floodplain at none, one, two or all projections.
  9. I decided to represent the different floodplains in three colors and code the properties (1 Ascendant; 0 Hope) and assign different colors to both. Another way I could have done this was to color code the chronology of flooding from green to red depending on 3 (floods in 2020), 2 (floods in 2050), 3 (floods in 2080) but I realized I also needed to distinguish the properties. I tried do choose "Many values" under Symbology and assign both coding for floodplain and coding for type of property (distinguishing them through a specific pattern applied to a solid color). The result was not satisfying because, especially in the overall map the zoom levels are not appropriate to show the details of the patterning.
  10. Exported Attribute table to Excel and performed a yearly rate of change analysis on the total number of buildings exposed to different floodplains as well as yearly rate of change for each property type. I used the following formula:
=(new_value-original_value)/(original_value)
where original_value represents the value that the percentage of change is based on, and new_value represents the value that has changed.
I then divided what I obtained by the number of years (2080-2015) that is 65
Maps 2, 3, 4, 5  - Small Multiple maps of single floodplains
Map 6 - Comparison with yearly rate of flooding of all buildings in Central and East Manhattan
Compare the rate of change All properties  in the CDs run the same analysis
Map 7 - Average H&A properties elevation in relation to floodplain hazard
For this maps I wanted to show how elevation may affect H&A BBLs being flooded under different floodplains. I used Zonal Statistics via Table, where under "Input raster or feature zone data" I selected the H&A BBLs properties, in Zone field I selected 'BBL' under "Input value raster" the DEM clipped and mask to Central and East Harlem.  Under statistics type I choose MEAN and I repeated the operation to obtain the MEDIAN elevation of the properties. I made a Table join on "BBL" between the table produced by zonal statistics and the table with H&A properties. I then opened the table and on MEAN I chose ' Summarize SUM Floodplain' to the average MEAN elevation and saved it outside the geodatabase as text file so I could work it on Excel.  The result is a table that expresses the average elevation at which BBLs flooded under different flood scenarios.