Option to create a vector field map from saved maps (OperatoR)

[arunge]

• [ ] add option to create a vector field map from saved maps using: https://r-graphics.org/recipe-miscgraph-vectorfield. Standard display options for generated map then apply.

[arunge]

@isomemo I have a question regarding the logic that should be used to define the vector field.

In the example from the link there is data that contains speed components in each direction:

library(gcookbook) # For the isabel data set
isabel
#>                x        y      z        vx        vy          vz         t
#> 1      -83.00000 41.70000  0.035        NA        NA          NA        NA
#> 2      -83.00000 41.55571  0.035        NA        NA          NA        NA
#> 3      -83.00000 41.41142  0.035        NA        NA          NA        NA
#> 156248 -62.12625 24.09679 18.035 -11.39709 -5.315139 0.009657148 -66.99567
#> 156249 -62.12625 23.95251 18.035 -11.37965 -5.275015 0.040921956 -67.00032
#> 156250 -62.12625 23.80822 18.035 -12.16637 -5.435891 0.030216325 -66.98057
#>           speed
#> 1            NA
#> 2            NA
#> 3            NA
#>  ...<156,244 more rows>...
#> 156248 12.57555
#> 156249 12.54281
#> 156250 13.32552

The function geom_segment requires values for xend and yend:

islice <- filter(isabel, z == min(z))

ggplot(islice, aes(x = x, y = y)) +
       geom_segment(aes(xend = x + vx/50, yend = y + vy/50),
                    size = 0.25)   # Make the line segments 0.25 mm thick

• To create a map we currently do plot latitude, longitude, estimates .
• If we have two maps and an operation, e.g. +,
  • we first create the resulting matrix for the selected operation that contains latitude, longitude, estimateAfterApplyingOperation
  • and than we do plot the data to the map.

What values should be used for xend and yend here if we want to apply geom_segment? We can also discuss this in our next meeting.

[isomemo]

@arunge we should discuss to better understand the problem!

[arunge]

@isomemo As discussed, you want to check if there is a different package that already contains the calculation to determine the length of the arrows (they should describe e.g. spread over time). So we will return to this issue later.