{"revision":"Study 06","units":"feet","accepted_for_2001_geometry":false,"source":"PANYNJ-18324 PDF 314–315 / SKA54 and SKA55/84","source_registration":"main-plaza-registration.json","banks":[{"id":"G01","name":"Northwest stairs","upper_edge":[[-326.6581073743434,212.3163150677462],[-326.6847966451018,228.2126632893099]],"lower_edge":[[-399.32777141005243,212.70516276647055],[-399.35446068081086,228.60151098803425]],"polygon":[[-326.6581073743434,212.3163150677462],[-326.6847966451018,228.2126632893099],[-399.35446068081086,228.60151098803425],[-399.32777141005243,212.70516276647055]],"source_pixels":[[1246,675],[1246,692],[1170,692],[1170,675]],"source":"PANYNJ-18324 PDF 315, SKA55/84; corroborating site plan PDF 314","upper_route":[[-190.92767591546402,239.64216305570636],[-190.89392183774015,219.53795795196407],[-326.6714520097227,220.2644891785281]],"lower_route":[[-399.34111604543176,220.65333687725246],[-447.1501055426085,220.90915773167643]],"location":"Between WTC 1 and WTC 6","destination":"West Street approach","evidence":"Stair-bank position and approximate envelope manually traced from the older plaza plan. Four repeated flight zones are visible; modeled subdivision is illustrative.","assumption":"16 ft starting drop, generated riser count, equal flight subdivisions, 8 ft intermediate landings, slab section and rails are display assumptions. Lower street levels and 2001 alterations are unverified.","default_drop_ft":16,"flights":4,"landing_ft":8,"accepted_for_2001_geometry":false},{"id":"G02","name":"Southwest stairs","upper_edge":[[-326.0771473321217,435.79515305970034],[-326.1038366028801,451.69150128126404]],"lower_edge":[[-399.7029911577742,436.1891171755131],[-399.7296804285326,452.0854653970768]],"polygon":[[-326.0771473321217,435.79515305970034],[-326.1038366028801,451.69150128126404],[-399.7296804285326,452.0854653970768],[-399.7029911577742,436.1891171755131]],"source_pixels":[[1247,914],[1247,931],[1170,931],[1170,914]],"source":"PANYNJ-18324 PDF 315, SKA55/84; corroborating site plan PDF 314","upper_route":[[-189.4392047535054,492.10334315224696],[-189.35678200557498,443.0116795268297],[-326.090491967501,443.74332717048213]],"lower_route":[[-399.7163357931535,444.137291286295],[-420.7522911719113,444.24985246224156]],"location":"Between WTC 1 and the hotel","destination":"West Street approach","evidence":"Stair-bank position and approximate envelope manually traced from the older plaza plan. Four repeated flight zones are visible; modeled subdivision is illustrative.","assumption":"16 ft starting drop, generated riser count, equal flight subdivisions, 8 ft intermediate landings, slab section and rails are display assumptions. Lower street levels and 2001 alterations are unverified.","default_drop_ft":16,"flights":4,"landing_ft":8,"accepted_for_2001_geometry":false},{"id":"G03","name":"Liberty west stairs","upper_edge":[[-212.7062210041483,682.047236513984],[-197.40734436505153,681.9653738405684]],"lower_edge":[[-212.82553774400952,753.1132638574452],[-197.52666110491276,753.0314011840296]],"polygon":[[-212.7062210041483,682.047236513984],[-197.40734436505153,681.9653738405684],[-197.52666110491276,753.0314011840296],[-212.82553774400952,753.1132638574452]],"source_pixels":[[1366,1178],[1382,1178],[1382,1254],[1366,1254]],"source":"PANYNJ-18324 PDF 315, SKA55/84; corroborating site plan PDF 314","upper_route":[[-179.94020513820732,529.4553512673945],[-202.88852009685223,529.5781452775179],[-202.96701795202415,576.3321106350581],[-204.8793775319113,576.3423434692352],[-205.0567826845999,682.0063051772763]],"lower_route":[[-205.17609942446114,753.0723325207375],[-205.25616723673642,800.7613771854285]],"location":"Between WTC 2 and the hotel","destination":"Liberty Street approach","evidence":"Stair-bank position and approximate envelope manually traced from the older plaza plan. Four repeated flight zones are visible; modeled subdivision is illustrative.","assumption":"16 ft starting drop, generated riser count, equal flight subdivisions, 8 ft intermediate landings, slab section and rails are display assumptions. Lower street levels and 2001 alterations are unverified.","default_drop_ft":16,"flights":4,"landing_ft":8,"accepted_for_2001_geometry":false},{"id":"G04","name":"Liberty east stairs","upper_edge":[[14.86456900241393,680.8295292469261],[31.119625431454153,680.7425501564219]],"lower_edge":[[14.745252262552697,751.8955565903873],[31.00030869159292,751.8085774998833]],"polygon":[[14.86456900241393,680.8295292469261],[31.119625431454153,680.7425501564219],[31.00030869159292,751.8085774998833],[14.745252262552697,751.8955565903873]],"source_pixels":[[1604,1178],[1621,1178],[1621,1254],[1604,1254]],"source":"PANYNJ-18324 PDF 315, SKA55/84; corroborating site plan PDF 314","upper_route":[[38.06878696891937,528.2888081712213],[23.19619164038096,559.2257297720694],[22.992097216933928,680.7860397016741]],"lower_route":[[22.872780477072695,751.8520670451353],[22.784862879280183,804.2165082455804]],"location":"Between WTC 2 and WTC 4","destination":"Liberty Street approach","evidence":"Stair-bank position and approximate envelope manually traced from the older plaza plan. Four repeated flight zones are visible; modeled subdivision is illustrative.","assumption":"16 ft starting drop, generated riser count, equal flight subdivisions, 8 ft intermediate landings, slab section and rails are display assumptions. Lower street levels and 2001 alterations are unverified.","default_drop_ft":16,"flights":4,"landing_ft":8,"accepted_for_2001_geometry":false}],"surfaces":[{"id":"g02-upper","name":"Walk south of the North Tower","source_pixels":[[1247,914],[1375,914],[1375,931],[1247,931]],"polygon":[[-326.0771473321217,435.79515305970034],[-203.68613421934873,435.140251672375],[-203.71282349010716,451.03659989393867],[-326.1038366028801,451.69150128126404]],"level":"upper","evidence":"Bounded exterior strip joining G02 to the west edge of the main plaza on SKA55."},{"id":"g03-upper","name":"West approach beside the South Tower","source_pixels":[[1366,1048],[1382,1048],[1382,1178],[1366,1178]],"polygon":[[-212.50212658070126,560.4869265843793],[-197.2032499416045,560.4050639109637],[-197.40734436505153,681.9653738405684],[-212.7062210041483,682.047236513984]],"level":"upper","evidence":"Narrow exterior approach along the west side of the South Tower; the northeast corner joins the main plaza."},{"id":"g04-upper","name":"East approach beside the South Tower","source_pixels":[[1604,1048],[1621,1048],[1621,1178],[1604,1178]],"polygon":[[15.068663425860962,559.2692193173214],[31.323719854901185,559.1822402268172],[31.119625431454153,680.7425501564219],[14.86456900241393,680.8295292469261]],"level":"upper","evidence":"Exterior strip between the South Tower and WTC 4, avoiding the unclassified rectangular feature to its east."},{"id":"west-court","name":"West Street approach court","source_pixels":[[1170,675],[1170,692],[1156,710],[1156,895],[1170,914],[1170,931],[1136,931],[1109,938],[1094,895],[1114,860],[1114,752],[1097,723],[1068,704],[1042,684],[1035,675]],"polygon":[[-399.32777141005243,212.70516276647055],[-399.35446068081086,228.60151098803425],[-412.76923696788225,245.5045683559875],[-413.0596790320182,418.4942401788865],[-399.7029911577742,436.1891171755131],[-399.7296804285326,452.0854653970768],[-432.23979328661284,452.2594235780851],[-458.06763731481254,458.94312198952974],[-472.34282600851765,418.8114580383722],[-453.1642817110266,385.9813539463244],[-452.99472634385523,284.9927887740375],[-469.2042540168956,257.96246795716826],[-496.90363874029293,240.34433721686884],[-521.7329141367563,221.7757779181531],[-528.4120430524301,213.3958790734152]],"level":"west","evidence":"Approximate lower walking area around the western tower frontage. Curved edge is a coarse polygon trace; grade interpolates between the two independently adjustable stair feet."},{"id":"liberty-court","name":"Liberty Street approach court","source_pixels":[[1366,1254],[1382,1254],[1382,1259],[1395,1270],[1590,1270],[1604,1254],[1621,1254],[1621,1324],[1411,1324],[1366,1310]],"polygon":[[-212.82553774400952,753.1132638574452],[-197.52666110491276,753.0314011840296],[-197.53451089043,757.7067977197837],[-185.1214431493019,767.9261566762923],[1.3336158896880193,766.9284553440389],[14.745252262552697,751.8955565903873],[31.00030869159292,751.8085774998833],[30.89041169435228,817.2641290004397],[-169.90734419379095,818.3385765890202],[-212.91345534180203,805.4777050578905]],"level":"south","evidence":"Lower exterior approach south of WTC 2, connecting the two stair feet. Display grade interpolates across the court; it is not a measured Liberty Street profile."},{"id":"church-walk","name":"Church Street approach","source_pixels":[[1902,635],[1968,635],[1977,934],[1902,934]],"polygon":[[300.65863311275535,171.55677317167186],[363.76649924902887,171.21908964383232],[371.9027001845928,450.76175472812696],[300.18921593882743,451.1454860097628]],"level":"church","evidence":"Bounded street-side strip from the separate Church concourse entrance to the east court. Curb annotations in A-E-24 indicate a lower street; the selected uniform level is only a comparison surface."}],"transition":{"id":"church-transition","name":"Church court grade transition","source_pixels":[[1878,813],[1902,813],[1902,934],[1878,934]],"polygon":[[277.43086578969843,338.12368385463884],[300.37918074834334,338.00088984451537],[300.18921593882743,451.1454860097628],[277.2409009801825,451.2682800198863]],"level":"transition","evidence":"Position of the transition within this band is unverified. The amber wire envelope connects two comparison levels; it is not a modeled historical stair, ramp or accessible route."},"interfaces":[{"id":"C1","name":"Church concourse entrance","point":[300.5989747428246,207.08978684340258],"level":"church","source":"A-E-24 PDF 213 and A-E-62 PDF 243; 1993 Port Authority visitor map","description":"A separate entrance through WTC 5 to escalators E-1 / E-2 and the concourse. Marker at the exterior approach only; entrance interior and escalator geometry are outside this grounds model."},{"id":"P1","name":"North Tower plaza interface","point":[-203.5102990237637,330.4113692714847],"level":"upper","source":"SKA55/84 PDF 315","description":"Approximate plaza-facing entrance zone on the older plan. Ground marker only; individual door positions, thresholds and the tower interior are not modeled."},{"id":"P2","name":"South Tower plaza interface","point":[-90.1111134679283,559.832025197054],"level":"upper","source":"SKA55/84 PDF 315","description":"Approximate north-side plaza entrance zone. Ground marker only; the Liberty Street concourse entrance is a separate lower-level connection."}],"defaults":{"G01":16,"G02":16,"G03":16,"G04":16,"church":6},"assumptions":{"bank_drop_ft":"Independent starting scenarios, not inferred from the plaza-to-concourse difference.","church_drop_ft":"Six feet is a rounded comparison scenario. A-E-24 shows curb annotations around EL325–326, but these have not been registered to the court threshold.","stair_section":"Four illustrative flights, three 8 ft landings; count generated near a 7 in riser. No code or historical compliance claim.","street_surfaces":"Lower courts terminate at bounded approaches; no full roadway, utility or drainage system is modeled."},"directory":[{"name":"Vesey exterior stair and escalator pair","state":"Modeled","connection":"Vesey sidewalk → raised northern walk → main plaza"},{"name":"Four west / south stair banks","state":"Provisional geometry","connection":"Main plaza → upper approaches → G01–G04 → lower West / Liberty courts"},{"name":"Church Street court","state":"Transition unresolved","connection":"Main plaza → east court → amber transition envelope → Church approach"},{"name":"Church E-1 / E-2","state":"Exterior marker C1","connection":"Church Street → WTC 5 entrance → concourse; distinct from the outdoor plaza stair pair"},{"name":"Vesey IRT access","state":"Reserved opening","connection":"Separate lower subway access at the Vesey assembly; full descent remains unmeasured"},{"name":"Other concourse exits","state":"Directory only","connection":"The 1993 visitor map identifies Vesey, Church / Liberty and West Street destinations. Precise exterior door locations are not registered."},{"name":"Tower plaza entrances","state":"Ground markers P1 / P2","connection":"Plaza-facing interfaces; building interiors and street-level lobby routes remain outside this model"},{"name":"Fountain terrace","state":"Modeled, adjustable","connection":"Eight illustrative short stair openings around the lower circular terrace"}],"exclusions":["Building and bridge geometry","Interior stairs / elevators and concourse passages","Unverified accessible routes or formal egress capacity","Unlabelled court objects, later memorial, furniture and planting species"],"research_update":"NIST NCSTAR 1-8 volume 3 was retrieved. The reviewed Appendix B divider is followed by other material rather than the promised local area maps, so no new geometry is attributed to those maps."}