rgee (version 0.2.0)

ee_map: Adds a given Earth Engine (EE) spatial object to mapview as a layer.

Description

Create interactive visualizations of spatial EE objects (Geometry, Image, Feature, FeatureCollection or ImageCollection) through mapview.

Usage

ee_map(eeobject, ...)
# S3 method for default
ee_map(eeobject, ...)
# S3 method for ee.geometry.Geometry
ee_map(eeobject, vizparams, center,
  zoom_start = 8, objname = "map", quiet = FALSE, ...)
# S3 method for ee.feature.Feature
ee_map(eeobject, vizparams, center,
  zoom_start = 8, objname = "map", quiet = FALSE, ...)
# S3 method for ee.featurecollection.FeatureCollection
ee_map(eeobject,
  vizparams, center, zoom_start = 8, objname = "map", quiet = FALSE,
  ...)
# S3 method for ee.image.Image
ee_map(eeobject, vizparams, center,
  zoom_start = 8, objname = "map", quiet = FALSE, ...)
# S3 method for ee.imagecollection.ImageCollection
ee_map(eeobject, vizparams,
  center, zoom_start = 8, objname = "map", max_nimage = 10,
  quiet = FALSE, ...)

Arguments

eeobject

An EE spatial object.

...

Ignored.

vizparams

List of parameters for visualization. See details.

center

The longitude and latitude of the map center. If it is not defined, ee_map will try to determine the centroid of the spatial EE object.

zoom_start

zoom level.

objname

character vector. Name of the map, or maps in case that the EE object be an ImageCollection.

quiet

logical; suppress info messages.

max_nimage

Max number of Image to display.

Details

ee_map takes advantage of the ee$Image()$getMapId python function for fetch and return a mapid and token that is suitable for use in a mapview. To achieve desirable visualization effects, it will depend on the type of spatial EE object . For either Image or ImageCollection, you can provide visualization parameters to ee_map by using vizparams. The parameters available are:

Parameter	Description	Type
bands	Comma-delimited list of three band names to be mapped to RGB	list
min	Value(s) to map to 0	number or list of three numbers, one for each band
max	Value(s) to map to 1	number or list of three numbers, one for each band
gain	Value(s) by which to multiply each pixel value	number or list of three numbers, one for each band
bias	Value(s) to add to each Digital Number (DN) value	number or list of three numbers, one for each band
gamma	Gamma correction factor(s)	number or list of three numbers, one for each band
palette	List of CSS-style color strings (single-band images only)	comma-separated list of hex strings
opacity	The opacity of the layer (0.0 is fully transparent and 1.0 is fully opaque)	number

If you add an Image or ImageCollection to the map without any additional parameters, by default ee_map assigns the first three bands to red, green and blue bands, respectively. The default stretch is based on the min-max range. For Geometry, Feature or FeatureCollection. The available vizparams are:

• color: A hex string in the format RRGGBB specifying the color to use for drawing the features. By default 000000.

• pointRadius: The radius of the point markers. By default 3.

• strokeWidth: The width of lines and polygon borders. By default 3.

Examples

# NOT RUN {
library(rgee)
ee_reattach() # reattach ee as a reserved word
ee_Initialize()

# Case: Geometry*
geom <- ee$Geometry$Point(list(-73.53522, -15.75453))
m1 <- ee_map(
  eeobject = geom,
  vizparams = list(pointRadius = 10, color = "FF0000"),
  objname = "Geometry-Arequipa"
)
m1

# Case: Feature
eeobject_fc <- ee$FeatureCollection("users/csaybar/DLdemos/train_set")$
  first()
m2 <- ee_map(eeobject = ee$Feature(eeobject_fc),
             objname = "Feature-Arequipa")
m2 + m1

# Case: FeatureCollection
eeobject_fc <- ee$FeatureCollection("users/csaybar/DLdemos/train_set")
m3 <- ee_map(eeobject = eeobject_fc, objname = "FeatureCollection")
m3 + m2 + m1

# Case: Image
image <- ee$Image("LANDSAT/LC08/C01/T1/LC08_044034_20140318")
m4 <- ee_map(
  eeobject = image,
  vizparams = list(
    bands = c("B4", "B3", "B2"),
    max = 10000
  ),
  objname = "SF",
  zoom_start = "8"
)
m4

# Case: ImageCollection
collection <- ee$ImageCollection("LANDSAT/LC08/C01/T1_TOA")$
  filter(ee$Filter()$eq("WRS_PATH", 44))$
  filter(ee$Filter()$eq("WRS_ROW", 34))$
  filterDate("2014-01-01", "2015-01-01")$
  sort("CLOUD_COVER")

m5 <- ee_map(
  eeobject = collection,
  vizparams = list(bands = c("B4", "B3", "B2"), max = 1),
  objname = c("Scene_2019", "Scene_2016", "Scene_2011"),
  max_nimage = 3,
  zoom_start = 10
)
m5
# }