Statistical computing language and software environment.

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6
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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
560 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, ...
1
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2answers
479 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
467 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 ...
2
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1answer
1k 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
336 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
1k 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
648 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
395 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
188 views

Extract number of vertices in each polygon in R

Simple question: how to extract the number of vertices in each polygon in R? I've found one way that works, but this is very slow (when x is a SpatialPolygonsDataFrame): y <- fortify(x) n.verts ...
15
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2answers
4k 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 ...
4
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1answer
506 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 ...
6
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1answer
1k 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
993 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
422 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
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1answer
2k 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 ...
10
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1answer
331 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
1k 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
359 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 ...
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1answer
174 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
2k 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
votes
1answer
139 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. saf class : RasterStack dimensions : 720, 1440, 1036800, 601 (nrow, ncol, ...
1
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1answer
87 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
150 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 ...
4
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2answers
470 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 ...
3
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1answer
384 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
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1answer
290 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 ...
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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. ...
2
votes
1answer
882 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
627 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
votes
1answer
2k 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
445 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
234 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
270 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
votes
2answers
414 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
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1answer
2k 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 ...
9
votes
2answers
2k views

Choropleth in R: custom breaks and plotting

I have a question with regard to plotting a choropleth map. What is recommended with regard to plotting a map with custom breaks? And make it look a bit attractive. In my script I have used the ...
3
votes
1answer
409 views

Find which grid cells contain a point

I have a dataframe with x,y coordinates. I've sampled 10 x,y coordinates from my dataframe: y <-c(24.637032,21.569813,21.687,19.677183,24.72438,21.433136,24.637032,22.21065,21.443762,25.273882) x ...
2
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1answer
362 views

Tearing in ggmap (R) after using spTransform and random point generation using splancs

I am using R and the package ggmap to try and generate some random points within the city limits of Chapel Hill, NC. I have downloaded the shapefile for the town of Chapel Hill from the Orange County ...
6
votes
1answer
119 views

What does shading indicate in home range plot?

I've simulated a home range in R using the clusthr function from the adehabitatHR package. The home range is made from 50 x,y coordinates. The output is attached. I'm trying to get clear on what ...
5
votes
1answer
1k views

Interpolating Maps - Statistical Learning Techniques vs Spatial Statistics Techniques

I have recently begun experimenting with the interpolation of variales over a whole country. I have good sized training set where I have several dependant variables (continuous and categorical) ...
11
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5answers
6k views

How best to fix a non-noded intersection problem in PostGIS?

I'm using a PL/R function and PostGIS to generate voronoi polygons around a set of points. The function that I am using is defined here. When I use this function on a particular dataset I get the ...
3
votes
1answer
220 views

Difference between gdal versions in reading raster on two machines?

I am using raster data from Afripop.org and using the R package raster (raster_2.0-41) to do all my computation. Everything has been working out just fine until I tried sending some jobs to a remote ...
6
votes
1answer
231 views

weighted mean across rasters in R

I have 2 rasters. One raster (bio1) contains temperature information across a continent. The other (sp) contains, for each cell, a probability of occurrence for a species. I would like to calculate ...
5
votes
2answers
3k views

Reading File Geodatabase using R?

File geodatabase (fgdb) includes numerous file geodatabase tables. As far as I know they exist as dbf files, but are within a Database.gdb. In ArcCatalog, the file pathway resembles ...
6
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3answers
745 views

Classifying point coordinates to countries or continents?

I have about 50 000 points (latitude and longitude), and I would like to find out in which country each of the points is located. It does not need to be super precise, though. (Or actually I only ...
4
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1answer
818 views

Self organizing maps and spatially Constrained Clustering in R

There are a few algorithms to perform spatial clustering in R but most of them focus on point pattern analysis (for example here). I would like to perform spatial constrained clustering for polygon ...
5
votes
2answers
1k views

How to extract values from a raster according to Lat and long of the values?

having 12 files with 12 hdrs for one year: these files are raster (projected WGS84,lat long): samples = 1440 lines = 720 bands = 1 header offset = 0 ...
0
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2answers
93 views

Reversing a “combine” function on a raster

I have a raster that I think was "combined" using an arcmap function. I am wondering if there is a way to extract just one raster layer from the combined dataset in order to use it separately, either ...
4
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1answer
240 views

Use csv file as raster file and stitch them together

I'm having an issue trying to stitch together 100 32bit Tiff files (coming from thermal imagery video and extracted as 32bit Tiff). I used Hugin to mosaic the pictures extracted from the video which ...