Statistical computing language and software environment.

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1answer
112 views

Remove parts of line that fall within a polygon

I have a polygon and two lines. How can I remove the portion of each line that falls within the polygon? # polygon coords <- matrix(c(-1.798123, -1.793072, -1.805767, -1.804129, -1.798123, ...
2
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1answer
1k views

Raster spplot legend: how to add a title beside it

After studying for a while how to create a chart from a raster object, I got almost everything I needed except to add a title to spplot's legend. What I tried: to use mtext("XXX (m)", side=4), ...
4
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2answers
132 views

remove segments of lines in R

I have these 3 lines: line1 <- matrix(c(-1.81209, -1.80470, -1.80616, 55.68024, 55.67947, 55.67544), ncol=2) line2 <- matrix(c(-1.80468, -1.80330, -1.79690, 55.68322, ...
1
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0answers
99 views

kriging Error dimensions do not match: locations xxxx data yyyy in R

I've been working (for hours) on a kriging problem. When I run an ordinary kriging model: y.ok <- krige(y~x, locations=data1,newdata=data2), I keep getting the message: Error dimensions do ...
6
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2answers
735 views

How to speed up the plotting of polygons in R?

I want to plot the country borders of North America over a raster image depicting some variable and then overlay contours on top of the plot using R. I have been successful in doing this using base ...
4
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1answer
250 views

R gridding and contouring options

I want to make an interactive web mapping application, which will grid and contour user data. My plan is to implement R scripts with Shiny, but the only R package I can find to do this is gstat. And ...
8
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2answers
187 views

spatial and spatiotemporal analyses

I have a dataset that consists of 247 mosquito traps placed in fixed positions and sampled weekly for 23 weeks. I also have dengue disease incidence data (indexed to home address) during the same time ...
5
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1answer
2k views

R : convert a spatial polygon objet to spatial polygon data frame

My goal is to modify an existing shapefile by merging certain polygons. After importing the shapefile and using the UnionSpatialPolygons command, I get the polygon outline that I want. However, this ...
11
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2answers
3k views

Clipping a raster in R

I am building a map for the northeastern U.S.A. The map background needs to be either an altitude map or a mean annual temperature map. I have two rasters from Worldclim.org which give me these ...
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1answer
284 views

Extraction of raster cell values based on 'rgeos' and 'raster' buffering approaches in R

I am trying to extract cell values from a raster that lie within a certain distance from a given location (i.e. buffering). Evaluating different approaches, I found out that applying gBuffer(..., ...
7
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2answers
392 views

Creating randomly shaped clumps of cells in a raster from seeds of 1 cell/pixel?

As my title says, I wish to "grow" clumps of cells from seeds within a raster. My base raster is full of 1's and 0's, 1's indicate land and 0's sea/NA areas. From the 1's I wish to select 60 random ...
6
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2answers
2k views

How to extract values from rasters at location of points in R?

My question is about extracting values from rasters at the location of points. With the function extract this is very easy, and the function gives me a dataframe with the values of all the variables ...
2
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2answers
703 views

Built a query for polygon Shapefile in R

I use the package maptools to read in Shapefiles in R. I would like to know if there is a function that can built up a query/subset to select only some Polygons based on a specific attribute in the ...
1
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2answers
173 views

Create Raster file in R from Matrix and latlons

I could use some advice on how to create a Raster file in R with a Matrix of datapoints and the coordinates stored in a seperate file. Both, data and coordinates come from a NetCDF file. I extracted ...
6
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3answers
1k views

How to efficiently read and reclassify many rasters in R

I've been tasked to create a suitability analysis of wave conditions in the Gulf of Mexico. I have 2 thousand or so raster files that are about 8 MB each (2438 columns, 1749 rows, 1km cell size). ...
3
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2answers
399 views

How to utilise single 'randomForest' model for several rasters in R?

I am using randomForest package in R to derive species distribution models. When I predict the model to the RasterStack containing the predictors in which the values were extracted to build my model, ...
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2answers
271 views

Calc vs. Overlay for speeding up band math in R 'raster' package?

Regarding yesterday's question about how to speed up band math in the R 'raster' package, would it be the same to use overlay to calculate NDVI instead of calc? If that's not the case, what's the ...
3
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1answer
251 views

How to speed up band math in R 'raster' package?

I have some GeoTiff rasters with over 100 bands in total, but they are not huge: resolution is about 1200x600 and total size is less than 7 mb. I'm trying to do a simple NDVI calculation: raster ...
1
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1answer
780 views

Reverse geocoding to get city, state, country data separately?

I have longitude and latitude data. I need to reverse geocode to get city, state, country data separately. I have checked google service. Google provides complete address to a micro level. ...
1
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1answer
194 views

random sampling from spatial points in R

Can anyone help me out on the best package to sample from a spatial point dataset? My dataset consists of a list of positions inside a region, and for each point I also have the name/number of the ...
2
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2answers
576 views

R Raster package: write NetCDF with time dimension

I am writing a rasterbrick with multiple layers to a netcdf file using the raster package in R: writeRaster(gridfile, "Data", "CDF", overwrite=TRUE, ...
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2answers
473 views

Plotting large numbers of objects on a chart using R and WKT format

I am retrieving thousands of geometry lines in WKT format from a Microsoft SQL Server database. I would like to plot all of those lines in one map, but I am having some difficulty with the code. How ...
1
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1answer
238 views

R: data.frame to raster object error

I have a data.frame consisting of a points with an associated continuos value and their X,Y coordinates. Altough it's not stored anywhere it's projection is a Lambert conformal conic. I think this is ...
2
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1answer
132 views

Extract number of vertices in each polygon in R

Simple question: how best to do this? I've found one way that works, but this is very slow (when x is a SpatialPolygonsDataFrame): y <- fortify(x) n.verts <- aggregate(y, by=list(y$id), ...
11
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2answers
2k views

How to efficiently read a kml file into R

Hi I'm working with huge .kml files (up to 10 Gb) and need an efficient way to read them into R. Until now I've been converting them to shapefiles via QGIS and then back into R with readShapePoly and ...
2
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1answer
347 views

Reading OGC geometry data from SQL server using R

I would like to write a script in R that creates a map using OGC geometry data that is stored on a Microsoft SQL server. Is there a way to read OGC geometry data using a query passed from R? Maybe ...
5
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1answer
561 views

Subset a SpatialPolygonsDataFrame by ID in R?

I've used the gIntersect function from the rgeos package to determine which polygons intersect in two SpatialPolygonsDataFrames (spdfs). The result is a logical matrix with rownames comprising the ...
0
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2answers
665 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 ...
5
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2answers
331 views

R packages for deriving spatial clusters from origin-destination matrix

I have a matrix of origin-destination flows and I am trying to figure out the best way to derive X number of functional spatial clusters from the data. I haven't done this particular type of analysis ...
2
votes
1answer
865 views

Image classification random forest [duplicate]

I am a newbie in R. I want to classify images using random forest in R. I am trying to learn the codes. But in the mean time, is there a push button (like a gui) in R that can be used for ...
9
votes
1answer
275 views

How to find the buildings (polygons) a user can see from a given location (point) and orientation (angle range)?

I would like to retrieve the set of buildings I can see from a given location (point -lat,lng) and orientation (interval of angles) + certainly with a given depth (e.g. 100 meters). Ideally I would ...
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2answers
776 views

Merging many rasters using Python

I have a list of many many rasters. I want to have a simple and easy to understand script that takes this and merges it into one big mosaic. I found a similar question but the accepted answer adivises ...
5
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1answer
251 views

Export spatial overlay from R package PBSmapping

After realising that the GEOS-library in Grass and the R package rgeos is incredibly slow, i found the packe "PBSmapping" to do the same thing, a Union of two Polygons and to cut the parts with no ...
1
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1answer
148 views

plot path of points

I have a sample of the address histories of households. ID ZIP1 ZIP2 ZIP3 01 XXXXX XXXXX XXXXX 02 XXXXX XXXXX XXXXX 03 XXXXX XXXXX XXXXX 04 XXXXX XXXXX XXXXX ... It's easy enough ...
2
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5answers
953 views

Counting road intersections and blocks

I have a shp file that consists of the road system of Mexico City. I would like to count the number of road intersections (crossings) and blocks (which I would define as a segment starting from one ...
0
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0answers
109 views

Why Stacking rasters return all values as NAs?

I have several rasters that I want to do some calculations ,basically calculating the moving average. dir2 <- list.files("D:\\2010+2011", "*.bin", full.names = TRUE) ...
1
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1answer
69 views

BIOMOD Error message: argument of length 0

I’m using the package BIOMOD in R to modelling habitat in rodent species. The data formatting works but I'm getting this error message when I run Modelling: ## Conputing the models ## ...
1
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1answer
127 views

Determining Pixel-by-pixel Catchments in ArcHydro

I used ArcHYDRO to prepare HydroDEM (5m) without sinks, Flow direction (FDR) raster, flow accumulation raster (FAC). As I understand FAC, value of pixel shows number of pixels that contribute to this ...
3
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2answers
340 views

How to cut a SHP based on another SHP using R

I have a Shapefile of points with certain information. I have another Shapefile with polygons corresponding to the states of the country I am working with (in this case Mexico). Since I only want to ...
2
votes
1answer
290 views

R: How can I create a polygon from several polygons and a line?

I have some spatial objects that I want to combine, namely three polygons and a line. The ultimate goal is to create a polygon that I can overlay on an area of a map of administrative divisions of the ...
1
vote
1answer
281 views

Rpy2 Unable to Load in Fresh QGIS Install

after installing qgis the a message given below is shown Unable to load the plugin: Unable to load required package rpy2. Please ensure that both R, and the corresponding version of Rpy2 are ...
1
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0answers
51 views

How to remove polygons in shapefile based on attributes in R [duplicate]

I have a shapefile where some attribute data is blank. I can delete those rows attribute table using na.omit. However, the polygons remain when I map the shapefile. I'm using R to make these changes. ...
1
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1answer
462 views

How to replace values in rasters in directory 1 based on condition on other rasters in another directory?

Having 10 raster files in one directory and another 10 rasters in another directory and both have the same dimensions. directory 1: files1 <- list.files("C:\\2010", "*.envi", full.names = ...
2
votes
1answer
474 views

R - Crop a pixel image produced by spatstat with a boundary shape

i am using the very good spatial statistic package spatstat to produce probability maps of spatial point patterns. Here is a simple working result from the examples to try out. require(spatstat) ...
7
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1answer
1k views

Removing rows in shapefile in R

I've imported a shapefile into R, and joined it to a table. My shapefile contains all the census ids, while my table only contains selected census ids. I'm now trying delete all the rows didn't get a ...
2
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1answer
241 views

Remove intersect of one polygon from another in R

I am trying to remove the intersect from Poly2 onto Poly1. Below are the coords of the 2 polygons. > coords1 [,1] [,2] [1,] 992.0161 7462.531 [2,] 950.1962 7413.532 [3,] 902.3632 ...
5
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1answer
159 views

Having trouble finding out what coordinate system a map is using, and how to convert it

I'm using Small Area shapefiles in Ireland from the Central Statistics Office (CSO) website. The link to these is here http://census.cso.ie/censusasp/saps/boundaries/ED_SA%20Disclaimer1.htm (Look for ...
4
votes
2answers
218 views

How to do a looping to Interpolate a huge Rainfall Time-series in GRASS GIS or R

In GRASS GIS I have access to a table in PostgreSQL Database with this structure: Table Name: rainfall_time_series Columns: id | year | month | day | value_mm | x | y | gauge_code Setting g.region ...
4
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2answers
282 views

Draw two separate lines from A to B and B to A

I have an Origin-Destination table like this Origin Destination Value A B 10 B A 100 A C 120 ... For all the locations A, B, C... I have another table indicating their location (Lat and Lon) Is ...
4
votes
1answer
1k views

Calculate distance between X/Y coordinates by individual in R

In R, I'd like to calculate the straight-line distance between each capture of an animal in my dataset - no need to take into account the curvature of the earth. I have a dataset that looks like ...