From a spacetime object, activate either the data or geometry contexts. The active object will then become available for manipulation.
Arguments
- .data
a spacetime object
- what
default NULL. Determines which context to activate. Valid argument values are
"geometry"and"data". If left null, returns.data.
Value
For activate() an object of class spacetime with the specified context activated. active() returns a scalar character with the active context can be either "goemetry" or "data".
Details
A spacetime object contains both a data frame and an sf object. The
data frame represents geographies over one or more time periods and the sf
object contains the geographic information for those locations.
Examples
df_fp <- system.file("extdata", "bos-ecometric.csv", package = "sfdep")
geo_fp <- system.file("extdata", "bos-ecometric.geojson", package = "sfdep")
# read in data
df <- read.csv(
df_fp, colClasses = c("character", "character", "integer", "double", "Date")
)
geo <- sf::st_read(geo_fp)
#> Reading layer `bos-ecometric' from data source
#> `/private/var/folders/zc/tg2xwck53dg9sls8x4ndzdc00000gn/T/Rtmp2RGXTr/temp_libpath2b6f5ea0db20/sfdep/extdata/bos-ecometric.geojson'
#> using driver `GeoJSON'
#> Simple feature collection with 168 features and 1 field
#> Geometry type: POLYGON
#> Dimension: XY
#> Bounding box: xmin: -71.19115 ymin: 42.22788 xmax: -70.99445 ymax: 42.3974
#> Geodetic CRS: NAD83
# Create spacetime object called `bos`
bos <- spacetime(df, geo,
.loc_col = ".region_id",
.time_col = "time_period")
active(bos)
#> [1] "data"
activate(bos, "geometry")
#> spacetime ────
#> Context:`geometry`
#> 168 locations `.region_id`
#> 10 time periods `time_period`
#> ── geometry context ────────────────────────────────────────────────────────────
#> Simple feature collection with 168 features and 1 field
#> Geometry type: POLYGON
#> Dimension: XY
#> Bounding box: xmin: -71.19115 ymin: 42.22788 xmax: -70.99445 ymax: 42.3974
#> Geodetic CRS: NAD83
#> First 10 features:
#> .region_id geometry
#> 1 25025010405 POLYGON ((-71.09009 42.3466...
#> 2 25025010404 POLYGON ((-71.09066 42.3397...
#> 3 25025010801 POLYGON ((-71.08159 42.3537...
#> 4 25025010702 POLYGON ((-71.07066 42.3518...
#> 5 25025010204 POLYGON ((-71.10683 42.3487...
#> 6 25025010802 POLYGON ((-71.08159 42.3537...
#> 7 25025010104 POLYGON ((-71.08784 42.3474...
#> 8 25025000703 POLYGON ((-71.12622 42.3504...
#> 9 25025000504 POLYGON ((-71.14175 42.3404...
#> 10 25025000704 POLYGON ((-71.13551 42.3487...