View source: R/interpolate_spatial.R
interpolate_spatial | R Documentation |
Interpolates a x-y surface from a data frame of spatial observations for plotting. Currently uses the idw
function.
interpolate_spatial( df, value, Subset = NULL, coords = c("lon.utm", "lat.utm"), station.col = "Station", strata.col = "From", name.col = NULL, id.cols = NULL, bin.method = "average", int.method = "idw", unit = NULL, shear = NULL, n.tile = 100, accuracy = 100 )
df |
data frame containing required information |
value |
Character referring to the name of the value column to be used for interpolation. |
Subset |
A subset argument as a character (i.e. with " ". See Examples). |
coords |
A vector of column names for x (longitude) and y (latitude) coordinates, respectively. It is recommended to use UTM coordinates instead of decimal degrees. See |
station.col |
Character. Name of the column that specifies unique stations (i.e. spatial points). Required. |
strata.col |
Character. Column that specify the sampling depth. |
name.col |
Character. Column giving sample names. Not required. |
id.cols |
Character vector. Identification columns that should be preserved together with value, From, To and UTM coordinate columns |
bin.method |
Character giving the method for binning data, if there are several observations for each spatial point. Alternatives:
|
int.method |
Character giving the method for interpolation. Currently only one option is implemented: "idw", inverse distance weighted interpolation using the |
unit |
The unit for |
shear |
Map tilting. Either NULL for non-tilted maps or a shear matrix, f.ex (matrix(c(2,1.2,0,1),2,2)) to shear the interpolation. This feature works poorly. |
n.tile |
Number of horizontal and vertical tiles. Default is 100 resulting to 10000 tiles. |
accuracy |
Number to which the extent of the interpolation area should be rounded. Given in meters. |
The function removes missing values (NAs) from value
column.
A word of warning about bin.method = "integrate"
: this functionality works only if samples have been taken consistently at same depths. In other cases, it is recommended to use bin.method = "average"
, although the user should be careful in comparing samples taken from different depths in general. The unit for integrated value is [amount]/m2, if the original value was [amount]/m3.
Returns a spatInt
object which is a list
Mikko Vihtakari
plot.spatInt
for plotting; interpolate_section
for
data(chlorophyll) ## load an example dataset x <- interpolate_spatial(chlorophyll, Subset = "From <= 10", value = "Chla") ## Interpolate plot(x) ## Plot
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