readVECT.Rdread_VECT moves one GRASS vector object file with attribute data through a temporary GeoPackage file to a terra "SpatVector" object; write_VECT moves a terra "SpatVector" object through a temporary GeoPackage file to a GRASS vector object file. vect2neigh returns neighbour pairs with shared boundary length as described by Markus Neteler, in https://stat.ethz.ch/pipermail/r-sig-geo/2005-October/000616.html. cygwin_clean_temp can be called to try to clean the GRASS mapset-specific temporary directory under cygwin.
read_VECT(vname, layer, type=NULL, flags="overwrite",
ignore.stderr = NULL)
write_VECT(x, vname, flags="overwrite", ignore.stderr = NULL)
vInfo(vname, layer, ignore.stderr = NULL)
vColumns(vname, layer, ignore.stderr = NULL)
vDataCount(vname, layer, ignore.stderr = NULL)
vect2neigh(vname, ID=NULL, ignore.stderr = NULL, remove=TRUE, vname2=NULL,
units="k")A GRASS vector file name
a layer name (string); if missing set to default of “1”
override type detection when multiple types are non-zero, passed to v.out.ogr
default the value set by set.ignore.stderrOption; NULL, taking the value set by set.ignore.stderrOption, can be set to TRUE to silence system() output to standard error; does not apply on Windows platforms
A "SpatVector" object moved to GRASS
Character vector containing additional optional flags and/or options for v.in.ogr, particularly "o" and "overwrite"
A valid DB column name for unique identifiers (optional)
default TRUE, remove copied vectors created in vect2neigh
If on a previous run, remove was FALSE, the name of the temporary vector may be given to circumvent its generation
default "k"; see GRASS 'v.to.db' manual page for alternatives
read_VECT imports a GRASS vector object into a "SpatVector" object.
vect2neigh returns a data frame object with left and right neighbours and boundary lengths, also given class GRASSneigh and spatial.neighbour (as used in spdep). The incantation to retrieve the neighbours list is sn2listw(vect2neigh())$neighbours, and to retrieve the boundary lengths: sn2listw(vect2neigh())$weights. The GRASSneigh object has two other useful attributes: external is a vector giving the length of shared boundary between each polygon and the external area, and total giving each polygon's total boundary length.
run <- FALSE
if (nchar(Sys.getenv("GISRC")) > 0 &&
read.dcf(Sys.getenv("GISRC"))[1,"LOCATION_NAME"] == "nc_basic_spm_grass7") run <- TRUE
GV <- Sys.getenv("GRASS_VERBOSE")
Sys.setenv("GRASS_VERBOSE"=0)
ois <- get.ignore.stderrOption()
set.ignore.stderrOption(TRUE)
#> [1] FALSE
if (run) {
execGRASS("v.info", map="schools", layer="1")
}
#> +----------------------------------------------------------------------------+
#> | Name: schools |
#> | Mapset: PERMANENT |
#> | Location: nc_basic_spm_grass7 |
#> | Database: /home/rsb/topics/grassdata |
#> | Title: Wake County schools (points map) |
#> | Map scale: 1:1 |
#> | Name of creator: helena |
#> | Organization: NC OneMap |
#> | Source date: Tue Nov 7 19:34:09 2006 |
#> | Timestamp (first layer): none |
#> |----------------------------------------------------------------------------|
#> | Map format: native |
#> |----------------------------------------------------------------------------|
#> | Type of map: vector (level: 2) |
#> | |
#> | Number of points: 167 Number of centroids: 0 |
#> | Number of lines: 0 Number of boundaries: 0 |
#> | Number of areas: 0 Number of islands: 0 |
#> | |
#> | Map is 3D: No |
#> | Number of dblinks: 1 |
#> | |
#> | Projection: Lambert Conformal Conic |
#> | |
#> | N: 248159.84441077 S: 203559.01136227 |
#> | E: 671714.55110786 W: 619215.13388253 |
#> | |
#> | Digitization threshold: 0 |
#> | Comment: |
#> | |
#> +----------------------------------------------------------------------------+
#>
if (run) {
print(vInfo("schools"))
schs <- read_VECT("schools")
print(summary(schs))
}
#> nodes points lines boundaries centroids areas islands
#> 0 167 0 0 0 0 0
#> primitives map3d
#> 167 0
#> cat TAG NAMESHORT NAMELONG
#> Min. : 1.0 Length:167 Length:167 Length:167
#> 1st Qu.: 42.5 Class :character Class :character Class :character
#> Median : 84.0 Mode :character Mode :character Mode :character
#> Mean : 84.0
#> 3rd Qu.:125.5
#> Max. :167.0
#>
#> CORECAPACI MOBILEUNIT MOBILECAPA GLEVEL
#> Min. : 0.0 Min. : 0.000 Min. :0.00 Length:167
#> 1st Qu.: 498.5 1st Qu.: 0.000 1st Qu.:0.75 Class :character
#> Median : 586.0 Median : 6.000 Median :1.50 Mode :character
#> Mean : 763.7 Mean : 7.318 Mean :1.75
#> 3rd Qu.: 903.0 3rd Qu.:11.000 3rd Qu.:2.50
#> Max. :2294.0 Max. :49.000 Max. :4.00
#> NA's :23 NA's :19 NA's :163
#> LOGRADE HIGRADE CALENDAR HASBASE
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> ISMAGNET PHONE ADDRNUMBER ADDRPREFIX
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> ADDRROOT ADDRTYPE ADDRSUFFIX ADDRCITY
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> ADDRZIPCOD SPED STATUS NODEID
#> Length:167 Min. : NA Length:167 Length:167
#> Class :character 1st Qu.: NA Class :character Class :character
#> Mode :character Median : NA Mode :character Mode :character
#> Mean :NaN
#> 3rd Qu.: NA
#> Max. : NA
#> NA's :167
#> CAPACITYTO ESL BOARDDIS2 PROJ_CAP
#> Min. : 0.0 Length:167 Length:167 Min. : 0.0
#> 1st Qu.: 543.0 Class :character Class :character 1st Qu.: 497.0
#> Median : 761.0 Mode :character Mode :character Median : 722.0
#> Mean : 867.0 Mean : 793.1
#> 3rd Qu.: 992.5 3rd Qu.: 975.0
#> Max. :2294.0 Max. :2390.0
#> NA's :20 NA's :2
#> NOTES
#> Length:167
#> Class :character
#> Mode :character
#>
#>
#>
#>
if (run) {
write_VECT(schs, "newsch", flags=c("o", "overwrite"))
execGRASS("v.info", map="newsch", layer="1")
}
#> Warning: GDAL Message 6: dataset /tmp/grass8-rsb-156212/RtmplaphF9/file270e65678b65c.gpkg does not support layer creation option ENCODING
#> +----------------------------------------------------------------------------+
#> | Name: newsch |
#> | Mapset: rsb |
#> | Location: nc_basic_spm_grass7 |
#> | Database: /home/rsb/topics/grassdata |
#> | Title: |
#> | Map scale: 1:1 |
#> | Name of creator: rsb |
#> | Organization: |
#> | Source date: Fri Mar 17 16:19:53 2023 |
#> | Timestamp (first layer): none |
#> |----------------------------------------------------------------------------|
#> | Map format: native |
#> |----------------------------------------------------------------------------|
#> | Type of map: vector (level: 2) |
#> | |
#> | Number of points: 167 Number of centroids: 0 |
#> | Number of lines: 0 Number of boundaries: 0 |
#> | Number of areas: 0 Number of islands: 0 |
#> | |
#> | Map is 3D: No |
#> | Number of dblinks: 1 |
#> | |
#> | Projection: Lambert Conformal Conic |
#> | |
#> | N: 248159.84441077 S: 203559.01136227 |
#> | E: 671714.55110786 W: 619215.13388253 |
#> | |
#> | Digitization threshold: 0 |
#> | Comment: |
#> | |
#> +----------------------------------------------------------------------------+
#>
if (run) {
nschs <- read_VECT("newsch")
print(summary(nschs))
}
#> cat cat_ TAG NAMESHORT
#> Min. : 1.0 Min. : 1.0 Length:167 Length:167
#> 1st Qu.: 42.5 1st Qu.: 42.5 Class :character Class :character
#> Median : 84.0 Median : 84.0 Mode :character Mode :character
#> Mean : 84.0 Mean : 84.0
#> 3rd Qu.:125.5 3rd Qu.:125.5
#> Max. :167.0 Max. :167.0
#>
#> NAMELONG CORECAPACI MOBILEUNIT MOBILECAPA
#> Length:167 Min. : 0.0 Min. : 0.000 Min. :0.00
#> Class :character 1st Qu.: 498.5 1st Qu.: 0.000 1st Qu.:0.75
#> Mode :character Median : 586.0 Median : 6.000 Median :1.50
#> Mean : 763.7 Mean : 7.318 Mean :1.75
#> 3rd Qu.: 903.0 3rd Qu.:11.000 3rd Qu.:2.50
#> Max. :2294.0 Max. :49.000 Max. :4.00
#> NA's :23 NA's :19 NA's :163
#> GLEVEL LOGRADE HIGRADE CALENDAR
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> HASBASE ISMAGNET PHONE ADDRNUMBER
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> ADDRPREFIX ADDRROOT ADDRTYPE ADDRSUFFIX
#> Length:167 Length:167 Length:167 Length:167
#> Class :character Class :character Class :character Class :character
#> Mode :character Mode :character Mode :character Mode :character
#>
#>
#>
#>
#> ADDRCITY ADDRZIPCOD SPED STATUS
#> Length:167 Length:167 Min. : NA Length:167
#> Class :character Class :character 1st Qu.: NA Class :character
#> Mode :character Mode :character Median : NA Mode :character
#> Mean :NaN
#> 3rd Qu.: NA
#> Max. : NA
#> NA's :167
#> NODEID CAPACITYTO ESL BOARDDIS2
#> Length:167 Min. : 0.0 Length:167 Length:167
#> Class :character 1st Qu.: 543.0 Class :character Class :character
#> Mode :character Median : 761.0 Mode :character Mode :character
#> Mean : 867.0
#> 3rd Qu.: 992.5
#> Max. :2294.0
#> NA's :20
#> PROJ_CAP NOTES
#> Min. : 0.0 Length:167
#> 1st Qu.: 497.0 Class :character
#> Median : 722.0 Mode :character
#> Mean : 793.1
#> 3rd Qu.: 975.0
#> Max. :2390.0
#> NA's :2
if (run) {
print(all.equal(names(nschs), as.character(vColumns("newsch")[,2])))
}
#> [1] TRUE
if (run) {
print(vInfo("roadsmajor"))
}
#> nodes points lines boundaries centroids areas islands
#> 266 0 355 0 0 0 0
#> primitives map3d
#> 355 0
if (run) {
roads <- read_VECT("roadsmajor")
print(summary(roads))
}
#> cat MAJORRDS_ ROAD_NAME MULTILANE
#> Min. : 1.0 Min. : 1.0 Length:355 Length:355
#> 1st Qu.: 89.5 1st Qu.: 91.5 Class :character Class :character
#> Median :178.0 Median :180.0 Mode :character Mode :character
#> Mean :178.0 Mean :179.8
#> 3rd Qu.:266.5 3rd Qu.:268.5
#> Max. :355.0 Max. :357.0
#> PROPYEAR OBJECTID SHAPE_LEN
#> Min. : 0.0 Min. : 1.0 Min. : 20.36
#> 1st Qu.: 0.0 1st Qu.: 89.5 1st Qu.: 763.32
#> Median : 0.0 Median :178.0 Median : 1601.23
#> Mean : 192.7 Mean :178.0 Mean : 4934.15
#> 3rd Qu.: 0.0 3rd Qu.:266.5 3rd Qu.: 9555.59
#> Max. :2025.0 Max. :355.0 Max. :64177.26
if (run) {
cen_neig <- vect2neigh("census")
str(cen_neig)
}
#> WARNING: Values in column <cat> will be overwritten
#> WARNING: Values in column <left> will be overwritten
#> WARNING: Values in column <right> will be overwritten
#> WARNING: Values in column <length> will be overwritten
#> Classes ‘GRASSneigh’, ‘spatial.neighbour’ and 'data.frame': 12128 obs. of 3 variables:
#> $ left : int 1 1 1 1 2 2 2 2 2 3 ...
#> $ right : int 2 18 176 177 1 3 20 176 182 2 ...
#> $ length: num 0.2814 0.1166 0.0849 0.2747 0.2814 ...
#> - attr(*, "external")= num [1:2537] 0 0 0 0 0.239 ...
#> - attr(*, "total")= Named num [1:2537] 0.7577 0.9377 0.753 0.0995 1.7322 ...
#> ..- attr(*, "names")= chr [1:2537] "1" "2" "3" "4" ...
#> - attr(*, "n")= int 2537
if (run) {
execGRASS("g.remove", flags="f", name=c("newsch", "newsch1"), type="vector")
}
Sys.setenv("GRASS_VERBOSE"=GV)
set.ignore.stderrOption(ois)
#> [1] TRUE