Statistical computing language and software environment.

learn more… | top users | synonyms

12
votes
4answers
1k views

How can I generate irregular grid containing minimum n points?

Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain ...
0
votes
4answers
82 views

Subsetting a x,y,z into a text file from a large xyz text file

I have a large txt file with x,y,z format. The file size is almost 8 GB. So I don’t want to process in ArcMAP. What I wanted to do is, I have a end coordinates for polygon shapefile and i have ...
0
votes
1answer
52 views

how to convert list of stack images to timseries files in R

Iam using bfast package for time series analysis. But it requires the files to be read as timeseries Problem: How to convert list of stacked images from 2000 t0 2013 into a time series and given as ...
2
votes
0answers
35 views

how to display the legend when the map contains external icons in R

I haven't found anything about the legend when the map contains icons external R (in png), is't possible to use the legend function or another function in R.
9
votes
2answers
131 views

Cleaning blocks pattern from urban LIDAR (blocks uplifted from streets)

We have a 1-meter LIDAR DEM from a city. A small subset can be downloaded from this link: This screenshot shows raw DEM with gray palette (darker belts are streets, and greyish and whitish ...
1
vote
1answer
39 views

R package for geographic regions

Someone told me about a R package with the definition of objects some regions and nations boundaries. I'm trying to find the border of Veneto, an italian region. What's the name of the package? Do you ...
6
votes
2answers
199 views

How do I convert a tweet into a point in QGIS?

I've been doing some research on using R to datamine twitter, but I haven't really found an answer or a decent tutorial for my question. I'm interested in pulling tweets from twitter with a certain ...
2
votes
1answer
175 views

Count overlapping polygons in single shape file with R

I have a shapefile of species ranges for ~ 346 species. Some species have multiple polygon ranges so there are 1,078 polygons and many polygons are multi-part. It looks something like this: I ...
3
votes
1answer
227 views

ggmap: create circle symbol where radius represents distance (miles or km)

I am trying to add a circle around a given latitude and longitude point where the circle size (radius) reflects distance in miles or km. I managed to come up with this example using ggmap, where I ...
0
votes
2answers
823 views

How can I generate a fishnet grid and a matrix of percentage of overlapping in R?

I'm trying use R for create a fishnet grid like in arcGIS with many cells of same size. In the arcGIS 9.3 we have the option of create a polygon with many small square polygons (eg. 1 x 1 degree of ...
3
votes
1answer
88 views

Extract areas of multi-part polygons (SpatialPolygonsDataframe) R

I have a SpatialPolygonsDataframe with multiple polygons, some of these have multiple parts (blue shapes below). In GIS-land it would be easy to get the areas of the individual parts of a multi-part ...
1
vote
0answers
34 views

Get pixel values ascii 50 files

I´m working with photos from a cam. The cam is arranged to take ndvi values instead of RGB for each pixel. I have several folders with 50 pictures in each folder as '*.asc' files the pictures. I am ...
2
votes
1answer
72 views

Extract all unique values from a RGB raster

I have a .png file in RGB format showing the intensity of ship traffic: For my analysis I need to convert it to a one-band raster with values between 0 and 1 where 0 means lowest density and 1 ...
2
votes
0answers
81 views

Plotting Bare Soil Line on landsat data in RStudio?

I am using RStudio with landsat package for computing and plotting the Bare Soil Line (BSL) on landsat tif image running on my HP Pavilion i7 laptop. The codes for running the BSL() function is as ...
1
vote
1answer
35 views

Another Way to Join a New Column to a DBF if OpenOffice is Giving a “Longer Than the Number of Digits Allowed” Error?

When I need to add a data column to a DBF, I always download the shapefile, open the DBF with OpenOffice for Mac, us a VLOOKUP( ) to add my data to a new column, re-save the file as a DBF, then open ...
12
votes
1answer
3k views

Instantiating spatial polygon without using a shape file 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 ...
1
vote
1answer
57 views

How can we retrieve the values ​​of the intervals in the legend in R

I have an elevation model plotted in R Code: library(raster) data(volcano) r <- raster(volcano) plot(r, col = topo.colors(20)) Plot: how can we retrieve the values ​​of the intervals in the ...
0
votes
1answer
35 views

smoothing a set point in R

I try to smooth R with a set point as follows: myshp <- shapefile("C:/Users/zina/workspace/Proj_Meteo/interpolate/DZA_adm/DZA_adm0.shp") ...
1
vote
0answers
44 views

Assigning widths to string fields using writeOGR() from rgdal?

I am currently working with MapInfo files in the .tab format. I am using R (3.1.0 for Windows) to read and write files in this format, however, I am encountering an issue with writeOGR() from the ...
2
votes
0answers
101 views

Converting LANDSAT-8 TIFF to matrix, data frame, or SpatialGridDataFrame formates

I need to correct the reflectance values of LANDSAT-8 data for steep terrain and find it too tedious and clunky in ArcGIS. The data I have is: LANSDAT-8 DEM (ASTER) Slope and aspect (Derived using DEM ...
1
vote
2answers
34 views

How to see whether a set of postcodes have a typical distribution to the whole postcode population of UK?

For my dissertation I have a dataset of postcodes of 9984 that I am converting to coordinates atm. I looking to find whether this dataset has a 'typical or 'atypical' spatial distribution compared ...
4
votes
2answers
211 views

join grid or polygon layers in R

I have two grids. Cells in each grid have an attribute. Size of grid cells differs between the two grids and the two grids do not overlay each other perfectly. I would like to create a new layer, ...
1
vote
2answers
98 views

Aggregating satellite night light data in R

I am working in R and having some difficulties with extracting values from a raster layer. What I am trying to do is aggregate satellite night light data from pixel to polygons. However, when I ...
2
votes
0answers
39 views

does the census bureau provide clipped / water-bounded files as nice as certain cities?

this question says they do but when i compare what i can find in the cartographic boundary files section of the census bureau's gis page, they don't look as good as certain shapefiles provided by the ...
0
votes
0answers
20 views

PostGIS raster write support in R

I want to push/write some generated raster layers to my postgres database directly in R. In theory this could be supported by the rgdal package, but sadly it isn't. In the latest version only copy, ...
0
votes
1answer
63 views

How to load postgis raster layers into R?

It is easy to get Vectorlayers into R from a PostgreSQL+PostGIS solution. library(rgdal) dsn="PG:dbname=plots host=localhost user=test password=test" plots = readOGR(dsn,"Plots") But how to do the ...
3
votes
1answer
129 views

problem with polygon smoothing in R

With R I am looking to smooth my Polygon: inter2.csv code: inter1 <- read.table("c:/inter2.csv", header=TRUE) # add a category (required for later rasterizing/polygonizing) inter1 <- ...
5
votes
4answers
194 views

Create a rectangular buffer from point shapefile using QGIS/GRASS/SAGA GIS/R

I have a points shapefile and I want to create a rectangular buffer (22 x 16 km) around each point. My goal is to create a 16x22 km grid where each of the points is the centroid of the grid. Seed the ...
4
votes
1answer
69 views

How to create a map colored by distance to nearest point in R

I'm new to GIS and R-- hope this question makes sense. I have a dataframe(geo07) containing two variables that record the long/lat values for about 6000 points (mat_long & mat_lat). These ...
2
votes
0answers
99 views

Place an image svg into an R plot [duplicate]

I have a set SVG icons (weather icons ) and I want to create a figure with svg superimposed images representation of a Shapefile. below my shapefiles and points representing the position where I ...
0
votes
2answers
287 views

Read ESRI shape file (polygon or polyline) in R Environment

How can I read ESRI polygon/polyline shapefile in R environment using rgdal or other library ? can I get a syntax for it ?
1
vote
0answers
27 views

SQLite Driver available with R's rgdal:writeOGR?

Does anybody know how I can get OGR's SQLite Driver to work with R's rgdal package? When listing the drivers in R with the ogrDrivers() command the SQLITE driver is missing..
3
votes
1answer
90 views

make a raster from dataset (csv)

I was trying to make a raster from an dataset (https://www.dropbox.com/s/jsm1x06lnzfbqty/data.csv?dl=0) code: inter1= read.table("c:/data.csv", header=TRUE) #convert to spatial points ...
0
votes
1answer
67 views

How to create an interrupted Mollweide map in R?

I am wondering if it is possible to create an interrupted Mollweide map in R. This question is similar to Discontinuous or Interrupted map projections? which does not really have a satisfactory ...
2
votes
1answer
113 views

How to change position of legend in levelplot of rasterVis in R? [closed]

By default legend is plot right side and I want to change it to bottom of plot. levelplot(CHL1, xlim=c(30,130), ylim=c(-20,30), xlab="", ylab="", margin=FALSE, col.regions=pal, ...
3
votes
2answers
132 views

Display two-dimensional color gradient for two different quantities

I have two overlapping raster layers. One contains quantity A from 0 to 100, and the other contains quantity B from 0 to 100. I'd like to create a map displaying both sets of data at once based on a ...
3
votes
2answers
163 views

Reprojection of shapefile in R and final extraction of values

I need to extract values from some raster files (stack) using a shape file. to bring both of them in the same CRS, I first transformed the shapefile using the EPSG codes. Opening it in an GIS software ...
3
votes
2answers
2k views

Converting NZMG (or NZTM) to latitude / longitude for use with R map library

I am a statistician with no background in GIS so apologies for the newbie question. We routinely use R for a range of statistical and graphic analysis and are interested in using its map library to ...
3
votes
2answers
205 views

Ripley's K function in QGIS Chugiak 2.4

I'm a noob user and I need to apply the Ripley's K-function on a point pattern in QGIS 2.4 Chugiak, but I don't know how to do. I think I need to use some plugin or extension (maybe GRASS, R or ...
4
votes
0answers
276 views

R Raster package loop over pixels

I want to perform a trend analysis for each pixel over it's time dimension. Therefore I wrote a loop over each pixel doing the calculation but this is extremely slow. I am sure there must be a faster ...
1
vote
1answer
198 views

converting coordinates from unusual DMS format to decimal

So I've been shared a dataset with what to me is an unusual format for degree min second data. In their own words: The coordinates provided are longitude and latitude in degrees minutes and ...
1
vote
1answer
512 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 ...
2
votes
1answer
70 views

Extracting data, not colors, from geotiffs in R

I'm an experienced R user new to GIS, but finding my way. I've recently run into an issue that I haven't been able to find any satisfactory documentation on (but could just be searching poorly). I'm ...
3
votes
2answers
117 views

Extract values from raster based on points and pixels adjacent to the point

I have an issue. I have a set of points (n=~2000) and I would like to extract the pixel values from multiple rasters (a single-raster solution is also ok) for location of that point as well as that of ...
3
votes
2answers
749 views

Converting osm file to shapefile (or data frame) in R

I was looking for a road shapefile for Australia today. I ended up going to Geofabrik. Open Street Map has data in .osm format. But they do not have one in .shp for Australia. If possible, I want to ...
3
votes
1answer
70 views

How to plot a full hemispheric orthographic projection in R

I want to make a plot like that using R: All I want is the country borders as seen from outer space, no fancy colors needed. It seems I need to use the spTransform function, but it gives me a "non ...
0
votes
1answer
85 views

calculate distance between points crossing the antimeridian

How can I calculate the distance between two points (lon/lat) if any of the points exceeds the antimeridian (+-180 longitude)? Im using the distVincentyEllipsoid {geosphere} to calculate the shortest ...
5
votes
1answer
202 views

Fixing orphaned holes in R

I'm trying to perform a union on a common field after merging two adjacent shapefiles. The shapefiles end up with at least one thin sliver of space between them. When I attempt a union I get the ...
2
votes
2answers
196 views

Convert shapefile with lists to data frame in R

I would like to ask some help for converting a shapefile to data frame. I downloaded data related to roads from Natural Earth. I imported the shapefile using shapefiles package like the following. ...
1
vote
1answer
66 views

How to convert raster to im object for point process model covariate in R

I am trying to convert a raster object to an .im object for use with a point process model in the spatstat package in R. I begin by creating the raster from a tiff file using the raster() package. No ...