Statistical computing language and software environment.

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2
votes
1answer
62 views

R generated files getting scrambled on import in ArcGIS

I want to put this out there just in case someone somewhere has experienced similar issues. I have a .csv file that I have generated in R 3.0 using this code: ...
2
votes
1answer
240 views

Null values coerced to zero (0) when exporting to csv or txt

I extracted values from several rasters, and in some cases, the value is null. However, when I export the attribute table to a csv or a txt file (from ArcMap), the null values are converted to 0. Is ...
0
votes
0answers
82 views

Dates are off when opening netcdf file in R

I have a netcdf file with the time dimension that goes from 12/2007 until 12/2010 with monthly time steps. I can see the correct dates in both arcgis and panoply. Panoply tells me this file is a ...
0
votes
1answer
464 views

How to load Georeferenced Scanned Maps in R

I have a geo-referenced scanned Map in GeoTiff format, which I would like to load into R. My intention is to plot some vector data (points and polygons) over this map using maptools package. Is ...
2
votes
1answer
568 views

how to extract a variable at specific time and depth from netcdf in r

I have the following netcdf file containing 7 variables and 4 dimensions. [1] "file data.nc has 4 dimensions:" [1] "depth Size: 12" [1] "time Size: 37" [1] "x Size: 305" [1] "y Size: 432" ...
2
votes
1answer
104 views

shape file for linked micromap not working

I am trying to replicate the example provided in the micromap R package of a linked map with the poverty rate for the 50 US states. I am trying to achieve the same results with a Shapefile from ...
3
votes
2answers
307 views

Exporting Maps as PDFs in R

In R, trying to export choropleth maps with density and frequency histograms as legends; have had success exporting as an image but not as a pdf. Exporting as an image (.png) works well; the map, ...
2
votes
2answers
82 views

How to extract values of one point dataset to second point dataset based on proximity using R?

I have to point shapefiles and would like to extract values from one point shapefile to another one based on some measure of proximity, i.e. for any given point in dataset x, extract the mean value ...
0
votes
1answer
435 views

Units of gBuffer from rgeos package

I have this polygon: library(maptools); library(sp) setwd(system.file("shapes", package="maptools")) columbus <- readShapeSpatial("columbus.shp") proj4string(columbus) <- CRS("+proj=longlat ...
3
votes
1answer
169 views

plotting a SpatialPolygons object using lines() without lines connecting separate polygons

This is almost an extension of a question asked on stackoverflow (http://stackoverflow.com/questions/12196440/extract-feature-coordinates-from-spatialpolygons-and-other-sp-classes), so I'll use the ...
8
votes
2answers
557 views

Simple way to detect/select border polygons of a shapefile

I am looking for a simple way to detect/select border polygons of a shapefile. Border polygons are here polygons that are not completely surrounded by other polygons i.e. polygons located at the ...
2
votes
2answers
582 views

Flow Accumulation in R

My apologies for such a general question. Is there an ArcGIS like implementation of Flow Accumulation for R? What I am trying to avoid: Using ArcGIS; Using Grass; Using RpyGEO (but will if need be) ...
2
votes
3answers
945 views

How to get count of non-NA raster cells within polygon using R

I've been running into all sorts of issues using ArcGIS ZonalStats and thought R could be a great way. Saying that I'm fairly new to R, but got a coding background. The situation is that I have ...
0
votes
1answer
333 views

Is there anyway to stack or merge .hdf files in R Studio?

I would like to be able to merge, mosaic, or stack several .hdf files. Does anyone know the package or library i should be looking for the tool to do this?
8
votes
4answers
3k views

R spplot tutorials

I'm in need of some tutorials/books/other training materials which cover how to use the spplot function in the sp package in R properly. As with many of these functions, it seems very powerful, but ...
1
vote
2answers
430 views

convert data.frame with no lat-long info to a raster

coders, I need to read in a .txt file into R and later do some spatial analyses on it. I’m working in R. 3.0.2 on a Windows server. I load the following libraries (probably more than I need): ...
2
votes
2answers
223 views

Determine if points fall upstream or downstream from a point on a line (river)

I have a set of fish species occurrences (lat/long) as points and set of rivers as lines. The fish species can of course only occur in the rivers (and not on land). I would like to determine whether ...
5
votes
1answer
945 views

calculate {minimal} distance between polygons in R

I have calculated the surface area of species distributions (merging polygons from shapefiles), but since this area can be comprised of quite distanced polygons, I would like to calculate some measure ...
4
votes
1answer
501 views

Extract points from regular data.frame with coordinates based on SpatialPolygonsDataFrame in R

I have a regular data.frame called datos.merged class(datosmerged) [1] "data.frame" The last two columns are the corresponding geographical coordinates datosmerged[1,c(23,24)] XCOORD ...
3
votes
1answer
403 views

remove land area from marine region polygons

In my pursuit to merge multiple polygons for the purpose of calculating the surface area of marine species distributions, using shapefiles from Marineregions, I am now trying to remove potential land ...
3
votes
1answer
499 views

Access Shapefiles from PostgreSQL/Postgis in R

I successfully setup a connection to my PostgreSQL/PostGIS database on Ubuntu Server from my Laptop (Ubuntu 12.04). Therefore I installed RODBC in R to setup a connection and I made a correct entry ...
0
votes
1answer
224 views

R for loops in Geospatial modelling environment

I am using the isectpolypoly command in GME and would like to iterate over several polygons ("proj_0_ect0207", "proj_1_ect0207"). My code is as follows: for (i in 0:30) { ...
1
vote
2answers
352 views

unionize intersections of merged polygons

[Updated quesion] I am using the following code to merged polygons from shapefiles for the purpose of calculating the surface area; library(maptools) library(rgdal) library(rgeos) #enter slots, ...
3
votes
1answer
272 views

Sample size for variogram modelling using the geoR package in R

I am trying to use the geoR package in R to model the variogram for a dataset of 15 000 sample points of bathymetry data. I intend to do a random split to create test (20%) and training samples (80% ...
2
votes
1answer
273 views

R or QGIS? Measuring elevation at points on DTM surface

Based on answers to this recent question I have been able to create natural looking digital terrain models using a combination of raster, rasterVis and rgl working on data held in ESRI ASCII grid ...
0
votes
1answer
105 views

Can rgdal use an external GDAL installation?

The README for rgdal contains the following text: file.show(system.file("README", package="rgdal")) For additional drivers, users of the CRAN Windows and CRAN OSX binaries can either convert ...
3
votes
0answers
432 views

Novel ways of filling in missing values in a raster

I am looking for robust ways to fill in missing values in some rasters. They all have a single layer. Missing values consist of single pixels to medium sized patches. Rasters are around 1000 x 1000 ...
5
votes
4answers
1k views

Calculating percent cover from shapefiles

I normally do not work with shapefiles, so I am a bit lost here. I have two shapefiles each with multiple objects. The first is a set of 32 polygons (each one is a plot). The second shapefile has ...
2
votes
1answer
186 views

Axis of rendered shape files not showing numbers that are latitude and longitude

I am using rgdal to render some shape file. The first is a set of building zones from NYC Open Data. The second is the NYC coast line from OSM. The Zone files seems to generally render an X axis ...
3
votes
2answers
300 views

Is there a way to speed up gIntersections for large spatial objects?

I'm attempting to perform a gIntersection of a big grid on a shapefile for country boundaries, so that I can calculate the % area of each grid cell that lies within the country. It takes a few seconds ...
2
votes
2answers
278 views

How to find the second highest value in a rasterStack in R

I have a rasterStack of rasters representing count data. I want to return a single raster whose values are the index of the raster with the second highest value for each cell. (I used which.max for ...
2
votes
1answer
145 views

R - Efficient way to segment rasters into sub-regions and sample… without using extract()

My question is: Is there a more efficient way to sample from a sub-region (defined by a shapefile read into a spatial object) of multiple rasters without having to use extract() for each region on ...
3
votes
1answer
428 views

ggmap, ggimage… - Saving and loading maps in R

In my current R project I'm working with the ggmap package to download and display maps. What bothers me is that you need internet access to load maps from google etc. I'd like to load a map from the ...
1
vote
1answer
401 views

How to do geometric correction of remote sensing data in R?

My challenge is to replace most of the remote sensing commercial tools with R code (I'm teaching assistant at the University and I would like to move to open source R code to show the added values to ...
2
votes
2answers
324 views

How to use ggplot with Processing in QGIS 2.0?

I'm trying to use R scripts within QGIS thanks to Processing. There are some example scripts available and I achieved to plots different columns of the attribute table (with the plot built-in ...
0
votes
1answer
525 views

Scale parameter of the GetMap function within RgoogleMaps

Within the R library called "RgoogleMaps", there is a function called "GetMap" which is used to save a georeferenced image file. The library's manual suggest that the SCALE parameter supposed to be ...
1
vote
0answers
98 views

Making spatial clusters by direct manipulation of raster pixel values using R

I think this is an overambitious million dollar question, but I'm always optimistic when I pose a question even though I feel like I left no stone unturned! I've processed a raster layer with pixel ...
4
votes
2answers
567 views

Convert polyline shapefile to points 1m apart and add xy coords in R

I have a table with xy coordinates in R and the following packages loaded: spatstat, raster, rgdal, sp and zoo. I do know how to use this to make a point shapefile, a line shapefile that goes through ...
7
votes
3answers
709 views

R - How to sampleRandom() from large raster without NA values

I have a number of vary large rasters which need to be randomly sampled with the return value being a matrix of x, y, and value. The raster package sampleRandom(raster,n, na.rm=TRUE, xy=TRUE) will do ...
1
vote
1answer
598 views

add unique IDs to mutiple polygons using loop or apply function

I want to add a unique ID (row number) for each polygon in a SpatialPolygonsDataFrame. I'm new at working with spatial data (and programming) so bear with me please. The goal is to merge all polygons ...
2
votes
2answers
727 views

Plotting a map of New Zealand with regional boundaries in R

I have been asked to make a map of New Zealand using R with regional boundaries. I need something exactly like this example of a map for Switzerland: ...
4
votes
1answer
2k views

R - Plotting shapefile with geographical (raster) data

Over the last few days I have been trying to plot a shapefile over data loaded into a data.frame within R. It should be a view of radar precipitation with an overlay of the country borders from a ...
4
votes
2answers
100 views

towgs Definition for European Datum 1950

I am new to all things GIS so apologies for a basic questions. I am trying to specify the CRS of a climatic raster layer in R. It is an equal area projection based on Europe Equidistant Conic and the ...
1
vote
2answers
2k views

Calculate distance in kilometers between two points

I have a few questions regarding the calculation of the distance between 2 postal codes. Take a look at the following code. ### # load the different packages we need ### require("rgdal") ...
0
votes
1answer
282 views

Update GEOS to 3.4

I want to use the rgeos function gDelaunayTriangulation (which requires GEOS 3.4) on my Mac, but when I load rgeos it says: > library(rgeos) rgeos version: 0.3-2, (SVN revision 413M) GEOS runtime ...
3
votes
1answer
71 views

How to re-ID polygons with sapply instead of for loop

I have a line of code that renames the id's of polygons in a SpatialPolygonsDataFrame by directly manipulating the ID slot of the polygon. I'm a bit slow when it comes to sapply, having used for loops ...
2
votes
0answers
152 views

Joining nearest neighbor small polygons using R

The figure shows a plot of numerous polygons (zoom in) made from a raster file by require(sp) require(raster) pol100 <- rasterToPolygons(r, fun=function(x){x==1}, dissolve=FALSE) There polygon ...
3
votes
2answers
496 views

Replicating QGIS style in R with rgdal

I want to use rgdal to plot a shapefile graduating the colour of features according to the values of one field (density). I couldn't find online detailed indications on how to do it and the package ...
3
votes
1answer
31 views

Equidistant projection for northern Delaware

I'm just getting started on a long-term project involving northern Delaware. Most of my distances will use great circle distances from the lat/lon, but for a few applications I'll wind up using ...
3
votes
2answers
1k views

Efficient way to handle NA values from analysis in R with Raster

I am not 100% sure if GIS is the correct stackexchange for this, but here we go. A problem I have been bested by: I have a raster layer of approximately 240 million cells. It could be a DEM or ...