Error in get(x)

[Nathan-Thompson]

Can't get the command to run. Here's what happens when I give it an SPDF:

>toTopoJSON(SPDF = USAdata)

Error in get(x) : object 'STATEFP10' not found

[joelgombin]

The first argument to toTopoJSON should be a named list, even where there is only one SPDF in the list. Does it work better that way?

[Nathan-Thompson]

Yep that fixed the get(x) issue! Thanks.

However now there's another problem---my SPDF object apparently uses spherical coordinates, which doesn't work with the --height and --width options that the package code puts into the topojson command as these require cartesian coordinates.

toTopoJSON(list(USA = USA))

topojson -o 'users/...'
bounds: -179.231086 18.86546 179.859681 71.441059 (spherical)
pre-quantization: 3.993km (0.0359°) 585m (0.00526°)
topology: 29758 arcs, 305436 points
if (options["coordinate-system"] !== "cartesian") throw new Error("--width and --height require Cartesian coordinates");
Error: --width and --height require Cartesian coordinates
at output ...
at notify ...
at ....

[joelgombin]

That's an issue with the underlying topojson utility,I suggest you reproject your SPDF to a map projection (for example a Mercator) before passing it to toTopoJSON (for example by using spTransform from the rgdal package). See for example https://www.nceas.ucsb.edu/~frazier/RSpatialGuides/OverviewCoordinateReferenceSystems.pdf.

[joelgombin]

Can I consider this issue closed, @Nathan-Thompson?

[Nathan-Thompson]

Do you have a way to check the command results?

Reprojecting with

USAdata2<-spTransform(USAdata, CRS("+init=epsg:3857"))

lets the command run but I can't seem to get the resulting .json back into R with either readLines() or the geojsonio topojson_read . I've tried a few different projection codes, can't seem to get it to work. Thanks!