Loading Esri ArcGrid export file (e00) in R?

Question

I am trying to load an ESRI ArcGrid export file into R. The file is located at- ftp://ftp.epa.gov/castnet/tdep/grids/n_tw/n_tw-2013.zip. The documentation for this file states, "Gridded data of the above variables are available in compressed ESRI ArcGRID export files" and not much else. Link to documentation here. My major problem is that this is an e00 file, an old output format of Arc.

The most straightforward way to load a raster normally (if this wasn't an e00 file) would be:

require(raster)
require(rgdal)    
test <- raster('/path/to/n_tw-2013.e00')

However, you will receive the error: n_tw-2013.e00 not recognised as a supported file format..

The RArcInfo package claims to be able to convert .e00 files into more useful Arc/Info binary coverage. To do this:

require(RArcInfo)
#first argument is the path to the e00 file, and the second argument is the new directory to create
e00toavc('/path/to/n_tw-2013.e00','/path/to/test1')

When I run this command it prints NULL, and creates two directories, test1, and info, however, both are empty. I'm not sure whats going wrong here.

How do I get this loaded into R as a raster so I can extract data to my specific lat/long?

Output of sessionInfo pasted here:

> sessionInfo()
R version 3.2.2 (2015-08-14)
Platform: x86_64-redhat-linux-gnu (64-bit)
Running under: CentOS release 6.7 (Final)

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8    
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
 [9] LC_ADDRESS=C               LC_TELEPHONE=C            
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods  
[7] base     

other attached packages:
[1] rgdal_1.2-5  raster_2.5-8 sp_1.2-4    

loaded via a namespace (and not attached):
[1] tools_3.2.2     Rcpp_0.12.3     grid_3.2.2      lattice_0.20-33

Answer 1

I have no problem reading in the file using rgdal 1.2-3 and raster 2.5-8:

require(raster)
require(rgdal)   
test <- raster('n_tw-2013.e00')
test
class       : RasterLayer 
dimensions  : 775, 1440, 1116000  (nrow, ncol, ncell)
resolution  : 4134.354, 4134.354  (x, y)
extent      : -2950369, 3003101, 115686.8, 3319811  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=aea +lat_1=0 +lat_2=29.5 +lat_0=45.5 +lon_0=0 +x_0=0 +y_0=-96 +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs 
data source : /Users/Martin/Desktop/n_tw-2013.e00 
names       : n_tw.2013 
values      : 0.8068619, 70.83445  (min, max)

---

R version 3.3.1 (2016-06-21)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.12.2 (Sierra)

locale:
[1] de_DE.UTF-8/de_DE.UTF-8/de_DE.UTF-8/C/de_DE.UTF-8/de_DE.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] raster_2.5-8 sp_1.2-3    

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.7       plotly_4.5.2      magrittr_1.5      munsell_0.4.3     colorspace_1.2-7 
 [6] viridisLite_0.1.3 lattice_0.20-34   R6_2.2.0          httr_1.2.1        plyr_1.8.4       
[11] dplyr_0.5.0       tools_3.3.1       rgdal_1.2-3       grid_3.3.1        gtable_0.2.0     
[16] DBI_0.5-1         htmltools_0.3.5   lazyeval_0.2.0    assertthat_0.1    digest_0.6.10    
[21] tibble_1.2        purrr_0.2.2       ggplot2_2.2.0     tidyr_0.6.0       base64enc_0.1-3  
[26] htmlwidgets_0.8   scales_0.4.1      jsonlite_1.1   

Answer 2

It appears you are dealing with an ArcInfo Exchange file - check this out How To: Import an ArcInfo interchange file (E00) in ArcGIS. Your trying to do this using R.

If you wanted to use a command-line approach to unpack e00 you could use E00compr - A Library to Read/Write Compressed E00 Files with is open source.

Using the 'e00conv' Conversion Program

'e00conv' is a command-line executable that takes a E00 file as input (compressed or not) and copies it to a new file with the requested compression level (NONE, PARTIAL or FULL).

e00conv [NONE|PARTIAL|FULL] input_file is the name of the E00 file to read from. output_file is the name of the file to create. If the file already exists then it is overwritten.

The last argument is optional and specifies the compression level to use when creating the output file (one of NONE, PARTIAL or FULL). The default is NONE (uncompressed).

If you had access to ArcGIS

The steps in ArcGIS:

ArcGIS 10.x - All ArcGIS licenses

1. Open ArcMap.
2. Click the ArcToolbox icon. ArcToolbox icon for ArcGIS 10.x
3. In ArcToolbox, expand Conversion Tools.
4. Expand 'To Coverage'.
5. Double-click 'Import from E00'.
6. In the 'Input interchange file' (E00 file) entry box, click Browse. Navigate to the desired directory and select the file. Name the output dataset.

Note: File naming restrictions outlined at the beginning of this article still apply at ArcGIS 10.x.

7. Click OK. A dialog window appears and indicates the process has completed. Click Close.
8. Click 'Add Data' [O-Image] ArcMap Add Data button for Desktop 10.x and navigate to the selected directory.

First convert the file to provide a compatible format for R, then try to reload the raster in R.

Answer 3

Use the function readGDAL from library(rgdal)

In your example should work:

n_tw_2013 <- readGDAL("path/to/the/file/n_tw-2013.e00")