3
votes
0answers
30 views

Resampling air temperature gridded data to sub-grid resolution

I'd like to obtain a 30-m resolution gridded dataset of air temperature from the ~1km gridded data of WorldClim, of Hijmans et al., 2005) for a mountainous region. The easiest procedure (I thought ...
3
votes
3answers
57 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 ...
0
votes
0answers
27 views

How to reference a number variable in r.mapcalc within QGIS graphical modeler

I need to run the following formula in r.mapcalc: (xor(abs(A-B),abs(A-C))>120)*A I would like to however use a user defined number input variable instead of the 120. I already have this variable ...
0
votes
0answers
51 views

Unable to access R from QGIS 2.4

I have been unable to run R from within QGIS on my computer. I have R version 3.03 installed and QGIS 2.4 on Windows 7. R is located at C:\Program Files\R\R-3.0.3\bin\and this is the path e specified ...
1
vote
0answers
31 views

QGIS using different R lib

I am working with a colleague who is learning QGIS and has a question about the R plugin. His library path (.libPaths()) has two folders: "C:/Users/RDCERWAW/Documents/R/win-library/3.0" "C:/Program ...
2
votes
0answers
95 views

Doubts with Ripley's K function Interpretation

I'm a self-taught person, I'm studying the K Ripley's function and I would need some person who give me some advices. First, I have written a little script of R in QGIS processor: ##Point pattern ...
2
votes
2answers
63 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 ...
0
votes
2answers
58 views

Is it permissible to redefine raster resolution (not resample!) in order that it be included in a SDM?

I'm fitting a SDM using R. A requirement is that all environmental predictor layers have the same extent, origin and resolution. I have high resolution bathymetry data (25m) that I will resample to ...
3
votes
2answers
150 views

How to automatically draw lines with a given angle from one single point in qgis 1.8?

I'm new to qgis so please be patient. I need to draw a bundle of lines all originating from the same point and with a 10° angle between each line (e.g. lines bearing at 0,10,20 ..90..110..220..350). I ...
1
vote
0answers
56 views

Is there any issue using R scripts with sextante processing framework?

I want to use R scripts from the module Sextante treatment QGIS , but I have many difficulties to configure the module in Sextante . Following the procedure described in the official documentation of ...
1
vote
1answer
22 views

RasterStack extract() for duplicated dates

I have a a Large RasterStack of temperatures and a 10570 points in a Large SpatialPointsDataFrame and I'm using extract() to assign the temperatures to each point in R. ...
3
votes
1answer
78 views

writeOGR column limit error: “Creating Name field failed”

I have a SpatialPointsDataFrame with 1057 elements and 4760 columns and want to export it to a shapefile. When I try to do this with writeOGR() I get an error: > ...
0
votes
0answers
73 views

How to open a raw binary raster in QGIS or R

I have a raw binary raster without a file ending, and no header file. I would like to open this in either QGIS or R and then convert to geotiff, but opening it seems to be a challenge. Here is a ...
3
votes
2answers
125 views

Select polygons that do not intersect any other polygon using QGIS, GRASS, SAGA or R

I would like to select the polygons of the layer below that do not intersect with any other polygon (within the same layer). How can I do this using QGIS, GRASS, SAGA or R?
1
vote
1answer
55 views

How to deal with empty corners in raster when calculating fragmentation index

I have clipped buffer area around coordinate from one big raster (forest cover). Such created raster was loaded in R where PatchStat function (library SDMTools) gives fragmentation index. After ...
1
vote
2answers
144 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
0
votes
0answers
66 views

Failure to display R script result plots in QGIS

I'm trying to run R scripts (3.0.2) from QGIS (2.0.1) on Windows 7 x64. There seems to be a known bug whereby the output results do not display in the QGIS GUI, but rather just an html path ending in ...
3
votes
3answers
400 views

Convert 800 .hdf4 files to Tiff using GRASS/QGIS/SAGA/GDAL/R

I've have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula, from February of 2000 to August of 2012 (really big data). How do I batch convert about 800 .hdf MODIS files to .tif ? ...
1
vote
1answer
709 views

How to process MODIS ndvi data using QGIS/GRASS/R?

I have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula (3 tiles), from February of 2000 to August of 2012 (really big data). I want to know how to deal with this kind of files. My ...
0
votes
0answers
104 views

Defining the boundary of a catchment area

I digitized contour lines from topographic maps and created a DEM. With the DEM, I estimated the boundary of a catchment area. Estimated positional accuracy of topographic maps is RMSE = 65 m, with a ...
3
votes
3answers
306 views

Per-pixel (statistical) calculations on a raster stack using GDAL

In R, it's relatively trivial to perform per pixel calculations based on a raster stack (e.g., get std.dev for each pixel on a 12 layer GeoTIFF). Unfortunately, the speed is less than desirable when ...
2
votes
1answer
145 views

Conversion of Latitude/Longitude to different map projection

I have two m*n matrices coming from a WRF-ARW simulation: one exclusively with longitude values and one with only latitude values. For both matrices I know the originatin projection (lambert conic ...
1
vote
3answers
147 views

How to access shapefile table in QGIS Modeler R scripts?

I need to develop .rsx scripts for QGIS 2.0.1 Modeler to do statistical elaborations on data tables of loaded vector layers. In this case I am not interested in accessing shapefile geometries, I'd ...
1
vote
1answer
140 views

Apply r.neighbours or Neighbourhood analysis (LecoS plugin for QGIS) to 3000 rasters

I need to apply r.neighbours or Neighbourhood analysis (QGIS plugin LecoS (or equivalent) to 3000 rasters and define a neighbourhood of 5 x 5 and calculate the mean. I suppose I need to create a ...
2
votes
1answer
191 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 ...
2
votes
2answers
222 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
377 views

Calculate area covered by a particular raster layer within polygons in QGIS

I am trying to extract information on vegetation cover within a set radius of point locations (my sites). I have succeeded in creating a new vector layer of circles with a 5 km radius around my sites. ...
6
votes
2answers
1k views

Resources on using R in QGIS for R users?

This is a very basic question, but I'm having a heck of a time figuring it out because so much of the QGIS documentation is oriented toward use of the GUI. I want to be able to run R scripts in QGIS, ...
2
votes
1answer
883 views

Is it possible to create and run custom R scripts in QGIS 2.0?

I am new to QGIS and most of the tutorials I have found are for 1.x and the overhaul has me confused. I would like to create R scripts and run them in QGIS. I have read here that it's possible using ...
1
vote
3answers
415 views

How to create random point in according polygon for each dataset entry in a list (with R)

I have an area divided into polygons, and a dataset of observations which has a common field with the polygon layer. I now would like to generate a random point for each dataset entry within the ...
5
votes
1answer
245 views

Why does ManageR and rpy2 not work in QGIS (1.8.0-Lisboa)?

I have been trying to get R scripts to function and ManageR to work within QGIS (1.8.0-Lisboa). (Windows 7). Python2.7.5. Two problems indicated that R was not working in QGis. First - when I run an ...
2
votes
2answers
318 views

What is faster for geoprocessing (intersect) big shapefiles?

I have 200 Mb shapefiles of polylines downloaded from OSM. I've been working with QGIS 2.0 in Ubuntu 64 Bit 8 Gb RAM to make some geoprocessing tasks and it's taking 2 days for processing. Once I've ...
2
votes
1answer
326 views

How do I convert longitude & latitude to a 3d (geocentric x,y,z) coordinate?

I'm interested in finding the centroid of a point cloud. I understand that to do this I need to convert latitude and longitude values to 3d coordinates, average them and then convert the resulting ...
5
votes
1answer
1k views

Shortest distance from point to line (big dataset)

What is the best method to calculate the distance from the nearest road for a series of address points in QGIS, having a very big dataset? (QGIS 2.0.1, Win XP) I read the answers to previous similar ...
3
votes
3answers
196 views

programmatically add field to shapefiles and insert shapefile name in every row of field

situation We have a folder containing 1 sub-folder for every participant in a study. The subfolders are named with the participants' ID, e.g., 1000, 1001, 1002, 1003. Every participant folder ...
3
votes
1answer
320 views

How to link R script to Algotithm output in QGIS modeler?

I constructed a simple R script for QGIS modeler (.rsx) that calculates groupwise summary statistics of a vector layer table (sum by field "subject" and "FRC"). The script correctly works. When ...
1
vote
1answer
296 views

r.surf.contour in QGIS 2.0

I have a problem with r.surf.contour. I create a DTM with v.to.rast.attribute and then use the r.surf.contour and it works fine in QGIS 1.9 but with QGIS 2.0 doesn't work. I have a contour shapefile ...
3
votes
1answer
402 views

How to cluster Raster data

I have thousands of Raster data concerning the ice coverage at the pole at different times (days) over several years. Now I would like to perform a cluster analysis. I want to split the data into ...
4
votes
2answers
517 views

Reduce the resolution of a shapefile in R (or QGIS if necessary)

I'm using shapefiles of history U.S. state boundaries from NHGIS to make maps in R. These shapefiles are much higher resolution than I need when making maps at the scale of the country: over 2 million ...
1
vote
0answers
74 views

level of spatial aggregation of polygons

I am looking for a method that allows me to obtain the spatial aggregation of polygons for each cell of a grid with 10kmx10km resolution. In each cell (10kmx10km), I want to be able to consider that ...
1
vote
2answers
337 views

What is the equivalent of arcpy “Con” in QGIS and/or R raster-package?

I'm looking for an equivalent of the conditional expression "Con" from arcpy in an open source spatial analysis package. I'd prefer to use QGIS or R. To provide some additional detail, I need to ...
0
votes
1answer
519 views

How to count number of polygons inside another polygon layer?

I am looking for a tool in arcgis 10.1 Qgis or R that allows me to count the number of polygons that are inside specific areas (defined also as polygons). My data consists in: 1 shape file with ...
3
votes
0answers
105 views

Can extracting raster values work in polygons' CRS without raster resampling?

I am trying to extract raster values using polygon layer with different CRS. Raster is in WGS84 (EPSG:4326) and the polygons in UTM (EPSG:23031). 1. If I want to work in the projection of the ...
0
votes
4answers
190 views

Buffer in QGIS/R is 650-670 m wide instead of 500 m

I am trying to make a 500 m buffer for my polyline layer. Unexpectedly, I receive buffer varying from 650 to 670 m, depending on location. As many resources recommend to use UTM before making a ...
1
vote
2answers
175 views

How to modify the results of a geological dataset from vertical to horizontal?

I have a 3-D point shapefile of a geological fault dataset consisting of x,y, and z columns. I need to create a raster dataset from this point dataset. I have been trying to do this in ArcGIS; ...
2
votes
2answers
1k views

Setting “R Folder” Path in QGIS Sextante

I have installed R via the R-Project website. I have QGIS installed via OSGEO4W (currently 1.9.0 Master), and have Sextante plugin installed and working with GRASS and SAGA providers. I am now trying ...
6
votes
1answer
122 views

Open source implementation of “feature density” algorithm

I'm working on a dataset of house searches - 1 polygon for each area in which people want to find a house from an online search tool. This produces many overlapping polygons. It would be great to ...
2
votes
1answer
263 views

Confused about reprojecting Google Maps (latlong) to Irish Grid TM65

Trying to transform points taken from Google maps (as latitude and longitude) to Irish Grid TM65 using the spTransform in R, and I'm confused on something. Everything I find on the net tells me ...
9
votes
1answer
281 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 ...
1
vote
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 ...