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Questions tagged [r]

Statistical computing language and software environment.

2
votes
3answers
1k views

NA values in dbf when exporting shapefile from R with writeOGR?

I´m writing an esri shapefile from R (2.14.1) on windows, using writeOGR in the rgdal package, in the resulting dbf file, NA values in the spatialpointdataframe (in numeric columns) are not translated ...
1
vote
1answer
746 views

Administrative level and coordinates from Yahoo GeoPlanet WOEID

The Yahoo GeoPlanet data can be freely downloaded from: http://developer.yahoo.com/geo/geoplanet/data/. If I understand it correctly, each WOEID corresponds to a unique location on earth, with ...
3
votes
1answer
101 views

How to determine if feature A and B are located in the same room?

I have created a map using MapWindows like the following: A little explanation here, the is a map of an elderly home. The yellow boxes are room and the white rectangles inside the yellow boxes are ...
12
votes
3answers
5k views

How to get the second nearest neighbor between two point patterns in R?

Is there a way to get the distances for the second nearest neighbor between two point patterns in R? The spatstat package has a function called nncross but it only applies to the nearest neighbors ...
17
votes
1answer
1k views

Monte Carlo simulation using QGIS and pgRouting on optimal sidewalk construction

I am new to spatial analysis and would appreciate some general direction on a project I am attempting, outlined below (I am starting from scratch). GOAL: To find the best locations to install 2000 ...
53
votes
6answers
120k views

How to open a shapefile in R?

I need to open a shapefile from ArcMap in R to use it for further geostatistical analysis. I've converted it into ASCII text file, but in R it is recognized as data.frame. Coordinates function doesn't ...
9
votes
3answers
10k views

Converting point to lat lon? [duplicate]

I have received a shapefile with measurement points to be analyzed, but no matter how I try, I can't find how to convert to lat lon. I suppose it would be good to know the projection but when I look ...
6
votes
1answer
4k views

Spatial distance join between polygon and points using R?

I'm figuring out how to do a Intersection (Spatial Join) between point and polygons from shapefiles. My idea is to get the closest points and those points that match completely inside the polygons. In ...
19
votes
2answers
13k views

Instantiating spatial polygon without using a shapefile in R

So, the usual way we read a shapefile in R is via the maptools package, like this: sfdata <- readShapeSpatial("/path/to/my/shapefile.shp", proj4string=CRS("+proj=longlat")) However, I have a use ...
0
votes
1answer
3k views

dependency ‘stringr’ is not available for package ‘rgeos’

Attempting to install rgeos package fails. Detailed error logs as follows:- > install.packages("rgeos", repos="http://R-Forge.R-project.org") Installing package(s) into ‘/Users/calvin/R/x86_64-...
4
votes
1answer
118 views

Is it possible to use RPy/RPy2 in a Geoprocessing Script that is exposed as a GP Task on ArcGIS Server?

Is it possible to publish a Script tool that uses the RPy/RPy2 module (or more generally any Python-to-R link) to ArcGIS Server 10 SP2? If so, what specifically do I need to do, i.e. Install R on the ...
15
votes
1answer
23k views

Converting a polygon into a raster using R

I'm trying to convert a shapefile into a raster within R. My approach is to read in the raster as follows: library(rgdal) # Loads SP package by default demo <- readOGR('F:/data/', 'shapefile') # ...
32
votes
7answers
31k views

Clustering spatial data in R? [closed]

I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance. I have already taken a look at this page and tried clustTool package. But I am not ...
4
votes
1answer
2k views

Superimpose grid on points, then aggregate points within each grid cell

I have a vector of presence/absence values (1,0) and a matrix of x,y coordinate data (projected) specifying the spatial position of each value (about 25,000 in total). I'd like to aggregate the point ...
27
votes
1answer
28k views

Raster legend in R: how to colour specific values?

I have an elevation model plotted in R r <- raster("example.dem") plot(r, col = topo.colors(20)) Some of the values are below sea level (0), and I'd like to have those display in red. How can I ...
13
votes
2answers
5k views

Random sampling of raster using R

Is there a straightforward way of randomly sampling a raster so that the output of the process is a raster? I'm using an example that I found on the r-sig-geo list and I have also tried the ...
7
votes
2answers
1k views

Is it possible to run an R script on a layer in QGIS?

I'd like to run an R script on a layer loaded in QGIS (to rotate a set of points created there using the Vector:Research Tools:Regular Points tool). I thought ManageR might work but cannot get it ...
4
votes
1answer
2k views

Simulation envelopes and significance levels

Many spatial analysis packages provide Monte Carlo techniques to simulate upper and lower “envelopes” for a summary statistic as a function of distance (e.g. K-function, nearest neighbor, etc…). I’...
10
votes
4answers
13k views

How can I export raster data from Arcmap to an R *.grd file format?

I want to work with raster data in R, but I have problems exporting my raster dataset from ArcMap. By "export data"/GRID I get a file with an *.aux extension. What I need is *.grd. Can anybody help ...
12
votes
1answer
650 views

Randomly altering raster map of habitat types?

I have a raster of habitat types for a specific area in Scotland. I need to create future habitat scenarios with changes in habitat to assess the population viability of a bird species. For example, ...
4
votes
3answers
1k views

Relationship between sp package in R; MapWindow; ArcGIS/QGIS?

I am using ArcGIS at office for some visualization work, but I feel it kinda dump to performing the same tasks several times for visualizing some data on different maps. I am think of automating it ...
4
votes
0answers
171 views

What open source solution would work best for auto extracting features from satellite images? [duplicate]

Possible Duplicate: Feature Extraction - Land cover I have been looking for an open source solution which would allow me to define a region (or collection of images) and extract features from ...
10
votes
4answers
3k views

Problems with NA values when reading .DEM file with R 'raster' package in Windows

I am trying to read a raster file in a .DEM format on windows using the 'raster' package in R. I get problems with NA values, when loading the data into R in Windows 7, but I do not have the problem ...
24
votes
7answers
4k views

Speed of various raster data formats

I'm having trouble locating any discussion or comparative benchmarking of different raster file formats (e.g., for use in data analysis in R). Does anybody have any insight into why particular formats ...
10
votes
3answers
2k views

How to cluster points based on a kernel density?

I have a large dataset with 36k points representing commercial land uses, each with a field containing the square footage. I have run a kernel density analysis on this dataset, producing a raster ...
17
votes
6answers
2k views

What are sources for current geo-statistical analysis classes/events: open or proprietary

I am keenly interested in geo statistics (and many other words with 3 t's :). I am not very programatically inclined but have been following several lists with this theme. One being the R filter on ...
4
votes
1answer
4k views

How to read multiple .gpx files in R [closed]

Suppose I have a number of .gpx files (these contain GPX waypoint data from a Garmin eTrex). I want to load them into R with different names and manipulate them. I can read one file thus: library(...
9
votes
3answers
762 views

Making county-level shapefile from set of points at 30 x30 km spacing using ArcGIS for Desktop?

I have a data set in csv form, like: latitude, longitude, value -45, 45, 10 .... I would like to calculate county level means from these data, using either ArcGIS or R+grass. I have the ArcGIS USA ...
10
votes
4answers
692 views

Does Google Maps API provide statistical tools or even raster to vector conversion?

I am working with a web developer who is working with Google maps API, trying to determine what pre-processing steps I should perform (e.g. in R and GRASS), and what can be done within the google maps ...
11
votes
1answer
840 views

Kriging on GRASS+R - cannot allocate vector of size 146.5 Mb

I'm trying to do a groundwater elevation map with an Ordinary Kriging on R, but always resulting on the lack of memory cannot allocate vector of size 146.5 Mb allocation (windows xp 32bit). ...
3
votes
1answer
643 views

spgrass6 and GIS_LOCK

I would like to thank's everyone first, i learn a lot here (gis.stackexchange) about GIS. I have one question about the use of GRASS within R session, i'm able to do some basic task, but i have one ...
4
votes
2answers
920 views

Altitude Above channel in GRASS 6.4

I'm fairly new to the GIS world and GRASS (come from econometric background), I would like to do some species distribution modeling using R and GRASS. So I started to read the book of Tomislav Hengl :...
4
votes
1answer
5k views

Convert a shapefile with northing/easting to ASCII raster with latitude/longitude

Linked below is a polygon shapefile whose projection is NAD83 and whose values are LU/LC codes. Coordinates are meters of northing and easting. I would like to convert it to an ASCII raster with ...
9
votes
3answers
4k views

R: Download a large DEM, change projection, and adjust to smaller scale

This is a process that takes just a few seconds in GIS software. My attempt to do it in R uses a large amount of memory then fails. Is there something wrong in my code, or is this just something R ...
6
votes
2answers
4k views

R: overlay a line on a raster stack/brick, and get profile of cell values along the line

I've combed through R's raster functions and vignettes and can't seem to get this working. I want to specify a line/vector across a raster stack (a DEM and possibly related variables), and get a ...
22
votes
2answers
62k views

find the centroid of a cluster of points

While searching the web, solutions for finding centroids of polygons come up rather often. What I'm interested in is finding a centroid of a cluster of points. A weighted mean of sorts. I would ...
12
votes
1answer
536 views

Spatial operators in R?

How can I do spatial selections or filters in R? I can do this in PostGIS using (e.g.): SELECT * FROM mypoint, mypoly WHERE ST_Within(mypoint.geom, mypoly.geom); and it is similarly a piece of cake ...
15
votes
3answers
4k views

Using R with ArcGIS for Desktop (without using GME)? [duplicate]

I am trying to learn R generally and making statistics for maps. I found some useful tricks for making maps with it but it is not the best you can do. My everyday GIS program is ArcGIS. How I can use ...
11
votes
3answers
3k views

Spatio-temporal interpolation in R or ArcGIS?

I'm trying to calculate average rainfall value from a number of points using Inverse Weighted Distance tool in ArcGIS 9.3. My problem is that: each point has it own time series, therefore the ...
44
votes
11answers
9k views

What is the most useful spatial R trick?

R is becoming pretty strong tool for handling and analyzing spatial data. I learned some useful things through questions like these at SO and thought it might be useful to have something simmilar, but ...
14
votes
7answers
3k views

How to implement value-by-alpha map in GIS?

I've been doing some background reading about cartograms recently and stumbled upon interesting alternative - value-by-alpha maps. Concept is described in more details here and full paper is ...
3
votes
2answers
1k views

Which ESRI defined geographic transformation do I need to use to convert my “ NAD83 Northern Virginia” data into WGS 1984 Web Mercator?

My title pretty much tells it all.. I have a number of datasets in which I want to batch project from NAD83 Northern Virginia Datum into the correct Web Mercator projection.. When I do a straight ...
22
votes
3answers
5k views

Using R with ArcGIS Desktop?

I've used the integration of R with QGIS, and found it a very uesful tool. Having taken a look at the R toolbox extension for 9 and the extension for 10 it appears they both offer only point ...