On Fri, 6 Jan 2017, helekua wrote:
Hi All,
I am a new GRASS user and would like to pull horizon data for multiple
points off of a DEM. I have been able to use the grass console to
accomplish this but I will need to run thousands of points from a gridded
dataset. I was hoping to apply a function or loop in R to accomplish this
however I am getting the following error in R while listing parameters.
Using Windows 10, R x64 3.3.2, rstudio 1.0.136 in a Grass GIS session
*Section of code:*
library(rgrass7)
doGRASS("r.horizon", flags = c("d"), parameters = list(elevation =
"w001001",
direction = 0.0, step = 180.0,
coordinates = -155.447804131,19.3115222633,
Use a numeric vector: coordinates = c(-155.447804131,19.3115222633), as
now the comma in -155.447804131,19.3115222633 is seen as starting a new
parameter:
list(elevation = "w001001", direction = 0.0, step = 180.0, coordinates =
-155.447804131,19.3115222633, file = "test_horizon1.csv")
$elevation
[1] "w001001"
$direction
[1] 0
$step
[1] 180
$coordinates
[1] -155.4478
[[5]]
[1] 19.31152
$file
[1] "test_horizon1.csv"
with the fifth list component having no name - hence the non-informative
error message.
A more modern approach is to say:
doGRASS("r.horizon", flags = c("d"), elevation = "w001001", direction =
0.0, step = 180.0, coordinates = c(-155.447804131,19.3115222633), file =
"test_horizon1.csv")
[1] "r.horizon -d elevation=w001001 direction=0 step=180
coordinates=-155.447804131,19.3115222633 file=test_horizon1.csv"
attr(,"cmd")
[1] "r.horizon"
treating the unnamed R function arguments as GRASS parameters.
Looping over coordinates= vectors should be feasible.
Hope this helps,
Roger
file = "test_horizon1.csv"))
*Error:*
Error in doGRASS("r.horizon", flags = flags, parameters = parameters) :
Invalid parameter name:
Any suggestions would be most appreciated.
Thanks,
Heidi
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Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: roger.biv...@nhh.no
http://orcid.org/0000-0003-2392-6140
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http://depsy.org/person/434412
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