Examples of OGRSQL

Basic examples

library(geovctrs)
library(vapour)
file <- "list_locality_postcode_meander_valley.tab"
f <- system.file(file.path("extdata/tab", file), 
                 package = "vapour", mustWork = TRUE)

(wkb <- geo_wkb(vapour_read_geometry(f)))[6:15]

## limit/skip
geo_wkb(vapour_read_geometry(f, skip_n = 5, limit_n = 10))

## read as wkt
geo_wkt(vapour_read_geometry_text(f, textformat = "wkt", 
        sql = "SELECT * FROM list_locality_postcode_meander_valley WHERE FID > 5 AND FID < 16"))

Using CAST to convert and WHERE to filter geometry type.

library(geovctrs)
library(vapour)
file <- "list_locality_postcode_meander_valley.tab"
f <- system.file(file.path("extdata/tab", file), 
                 package = "vapour", mustWork = TRUE)

## find all multi-geoms and cast to multilinestring
wkb <- geo_wkb(vapour_read_geometry(f, 
                     sql = "SELECT CAST(OGR_GEOM_WKT AS geometry(MULTILINESTRING)) from 
                     list_locality_postcode_meander_valley 
                WHERE OGR_GEOM_WKT LIKE 'MULTI%'"))