I'm relatively new to using Shapefiles in R. I want to create visualizations of country and district level data for India for which I'm using maptools in R. For the shapefiles, I got the data from gadm.org which includes state/district/subdistrict level data for India.
However, I'm trying to load the file in R and it's just not happening.This is my code :
library(maptools)
dist <- readShapePoly("IND_adm2.shp")
Here IND_adm2.shp is the district level shape file for India.
R is unable to read the file, giving me this error:
"Error in getinfo.shape(filen) : Error opening SHP file"
I'm not really sure what the problem is.I have R 3.0.1, have the files in the appropriate directory but something's just not right. I'm also new to making maps in R so it's been a bit annoying. Any ideas on how to fix this?
You could use the package rgdal
library(rgdal)
library(sp)
shp <- readOGR("path/to/shpfiles", "IND_adm2")
plot(shp)
Related
I am trying to read a shapefile
library(sf)
wards <- read_sf("Shape_files/benguluru_ward_boundaries_reprojected.shp")
and I am getting this error
Error in CPL_get_z_range(obj, 3) : z error - expecting three columns;
I googled it and it seems it has to do with z-dimension but I couldn't find a solution. How to solve this? Thanks in advance.
Edit:
This is what I am getting when I load the sf package
> library(sf)
Linking to GEOS 3.9.3, GDAL 3.5.2, PROJ 8.2.1; sf_use_s2() is TRUE
you can get the files here
Edit2: I was able to solve this by running extract z values as mentioned here and there dropping it while exporting the layer. I am able to read that new layer without any issues.
I'm trying to replicate the maps shown in this short example (Choroplethr v3.6.0 is now on CRAN) for California, but I'm having trouble with the tract_choropleth function for areas that are not in NY. I get the error message below. I'm able to import the underlying tract data for all areas, but I'm having trouble mapping the non-NY ones. Thanks in advance.
# Load all packages (DONE)
# Install api key (DONE)
# Get Tract-Level Demographics
ca_stats = get_tract_demographics("california")
# Create choropleth map with the function tract_choropleth
ca_stats$value = ca_stats$per_capita_income
tract_choropleth(ca_stats, "california", title = "2013 Per Capita Income\nCensus Tracts", legend="Dollars")
Error message returned:
Error in ogrInfo(dsn = dsn, layer = layer, encoding = encoding,
use_iconv = use_iconv, : Cannot open layer In addition: Warning
message: In unzip(file_loc, exdir = cache_dir, overwrite = TRUE) :
error 1 in extracting from zip file
I'm the author of the tigris package that choroplethr uses to get Census tract boundaries. That error shows up in the event of a corrupted download from the Census Bureau website. Ari's solution will work; you can also try:
library(tigris)
options(tigris_refresh = TRUE)
This will direct tigris to re-download the shapefile from the Census Bureau website, and allow you to still use caching. Once it is fixed, set options(tigris_refresh = FALSE) to control future re-downloads.
Thank you for using choroplethr.
I have never gotten this error myself, but it's possible that it relates to a caching issue with the tigris package. I say that because it looks very similar to this issue.
Here is the code which solved that user's problem:
library(tigris)
options(tigris_use_cache = FALSE)
That code causes tigris to not use its cache.
Please type that code into your R session and try the choroplethr code again.
I want to shift some of my most commonly used shapefiles to github. I have a new package in development. It worked when built in RStudio, but when I pull the package from github and run it I get the error "Error in getinfo.shape(filen) : Error opening SHP file". When I look inside the package the shapefiles are in place in the data folder. They're being called by individual functions, e.g.
load_lon = function(){
require(maptools)
lon <<- readShapePoly('data/london_outline_simple.shp', proj4string=CRS('+init=epsg:27700'))
}
Presumably this method means R is wrongly looking for subfolder 'data' in the working directory. But I can't think how else to call them, as data() doesn't support shp. Grateful for advice how to load them in.
In line with #josh-obrien's comment, the answer is to put data files in a subfolder of inst, whereupon they'll be compiled with the code when the package is built. I've put the shapefiles in:
$SOURCEDIR/inst/external/
These are installed via functions such as:
load_lon = function(){
require(maptools)
path = system.file("external/london_outline_simple.shp", package="londonShapefiles")
lon <<- readShapePoly(path, proj4string=CRS('+init=epsg:27700'))
}
Check out the working github package for full working example.
I'm trying to import a SRTM dataset into R. I've downloaded the data in a tif file however am having trouble reading it in "R".
Ive tried using the following code:
t = readTIFF("srtm_56_06/srtm_56_06.tif", as.is=TRUE)
load('srtm_56_06/srtm_56_06.tif')
read_file<-as.matrix(raster("srtm_56_06/srtm_56_06.tif")
However I am still getting error messages:
load('srtm_56_06/srtm_56_06.tif')
# Error: bad restore file magic number (file may be corrupted) -- no data loaded
# In addition: Warning message:
# file ‘srtm_56_06.tif’ has magic number 'II*'
# Use of save versions prior to 2 is deprecated
library(raster)
t = readTIFF("srtm_56_06/srtm_56_06.tif", as.is=TRUE)
# Error: could not find function "readTIFF"
read_file<-as.matrix(raster("srtm_56_06/srtm_56_06.tif") + min(read_file)
# Error: unexpected symbol in:
# "read_file<-as.matrix(raster("srtm_56_06/srtm_56_06.tif")
# min"
Can anyone help me with the commands to import this data. I'm a novice at "R" and a little lost.
Just read it with raster, but note you depend on rgdal being installed as well to read a .tif.
library(raster)
library(rgdal)
r <- raster("srtm_56_06/srtm_56_06.tif")
If that works, try
plot(r)
r
If it's really a "TIFF" then that should be fine, if it's really a GeoTIFF then you'll have a sensible map as well. (If it's something else that GDAL can read you might get a good result anyway, remember the extension of a file is not a reliable indicator of its contents).
The SRTM clue suggests that this is a single band DEM file from the tiled global SRTM data set. If it's somehow a "multi-band image" then you could read that with brick and plot with plotRGB (but I really doubt that is the case here). Note that there is a native binary format for SRTM that raster/rgdal could read as well but either they distributed .tif as well or someone else converted it.
There are a number of misconceptions in your code:
load is for a particular file type created from R (not these .tifs)
readTIFF is not in package raster
read_file would be a sensible matrix, if you have rgdal installed (which raster must use to load a .tif), but why throw away the spatial metadata?
I'm trying to learn how to plot shapefiles with ggplot2 and I found a wiki at:
https://github.com/hadley/ggplot2/wiki/plotting-polygon-shapefiles
I downloaded and extracted the zip file provided into new directory on my desktop ( http://www.epa.gov/nheerl/arm/documents/design_doc/ecoregion_design.zip ).
I started reading through the article, going line by line but I'm running into a problem with fortify.
require("rgdal")
require("maptools")
require("ggplot2")
require("plyr")
> my_dsn <- "directory here"
>
> utah = readOGR(dsn=my_dsn, layer="eco_l3_ut")
OGR data source with driver: ESRI Shapefile
Source: "directory here", layer: "eco_l3_ut"
with 10 features and 7 fields
Feature type: wkbPolygon with 2 dimensions
> utah#data$id = rownames(utah#data)
> utah.points = fortify(utah, region="id")
Error: isTRUE(gpclibPermitStatus()) is not TRUE
I looked at the ?fortify help page and get the jist of how it should be used. I think its being used correctly. I also found another question with the same error on SO,
Getting error while using fortify function in R (ggplot)
but I can't figure out how to apply what is being said for my solution. I might help if I had access to dropbox right now but I don't.
The short answer is to install the rgeos package and include it at the top.
A longer answer can be found here (and elsewhere): https://stat.ethz.ch/pipermail/r-sig-geo/2012-July/015685.html