Invalid points in shapefile IBTrACS.ALL.list.v04r00.lines.shp

[Julian O'grady]

Hi,

I'm loving the BTrACS shapefile format. Unfortunately it has some invalid spatial-lines. The start and end point of the invalid geometry appear to be exactly the same point.

For example in R

TCs <- raster::shapefile(paste0(TCdir,"IBTrACS.ALL.list.v04r00.lines.shp")) #very slow!

invalidLines = which(!rgeos::gIsValid(TCs,byid=TRUE) )

TCs[invalidLines[1],]

class       : SpatialLinesDataFrame 

features    : 1 

extent      : -73.5, -73.5, 32.5, 32.5  (xmin, xmax, ymin, ymax)

crs         : +proj=longlat +datum=WGS84 +no_defs 

variables   : 168

names       :           SID, SEASON, NUMBER, BASIN, SUBBASIN,      NAME,            ISO_TIME, NATURE,  LAT,   LON, WMO_WIND, WMO_PRES, WMO_AGENCY, TRACK_TYPE, DIST2LAND, ... 

value       : 1851256N33287,   1851,     15,    NA,       NA, NOT_NAMED, 1851-09-13 00:00:00,     TS, 32.5, -73.5,       50,       NA, hurdat_atl,       main,       370, ... 

> raster::geom(TCs[invalidLines[1],])

     object part cump     x    y

[1,]      1    1    1 -73.5 32.5

[2,]      1    1    1 -73.5 32.5

 

QGIS analysis (also ueses geos) below.

What should I do with these lines? Drop them? move the geometry of the second point very slightly?

Cheers,

Julian

     

QGIS version: 3.16.4-Hannover

QGIS code revision: 654e76b3cb

Qt version: 5.11.2

GDAL version: 3.1.4

GEOS version: 3.8.1-CAPI-1.13.3

PROJ version: Rel. 6.3.2, May 1st, 2020

Processing algorithm…

Algorithm 'Check validity' starting…

Input parameters:

{ 'ERROR_OUTPUT' : 'TEMPORARY_OUTPUT', 'IGNORE_RING_SELF_INTERSECTION' : False, 'INPUT_LAYER' : 'Z:\\work\\archive\\IBTRACS\\IBTrACS.ALL.list.v04r00.lines\\IBTrACS.ALL.list.v04r00.lines.shp', 'INVALID_OUTPUT' : 'TEMPORARY_OUTPUT', 'METHOD' : 2, 'VALID_OUTPUT' : 'TEMPORARY_OUTPUT' }

Execution completed in 243.89 seconds

Results:

{'ERROR_COUNT': 1258,
'ERROR_OUTPUT': 'Error_output_1050ed76_8d36_4373_ac9b_2028ad2d89a0',
'INVALID_COUNT': 1258,
'INVALID_OUTPUT': 'Invalid_output_bc18a5e3_c239_4011_926f_d4b680bf19f1',
'VALID_COUNT': 684065,
'VALID_OUTPUT': 'Valid_output_669cbbc5_48eb_480e_ab05_315a953afd72'}

Loading resulting layers

Algorithm 'Check validity' finished