Statistical computing language and software environment.

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5
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3answers
371 views

Create Zonal Grid in R

Suppose I have a n*n raster, and I want to create k square blocks (k can be divided exactly by n*n ) for zonal analysis: for example, when n = 4 and k = 4 a 4*4 raster is create with value 1 1 2 2 ...
5
votes
1answer
237 views

Spatial graphing, distribution of polygon area over latitudes

Given a polygon in a PostGIS database, what is the best way to create a graph of its distribution over a range of latitudes? I'm picturing a graph of a curve, where the proportion of the total area ...
4
votes
2answers
399 views

Converting shapefile to raster: Character attributes

I've got a shapefile that I would like to convert into a raster, but the trick is that the attribute I want a raster version of is character data. I'm familiar with geoprocessing using GDAL (in the ...
4
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0answers
559 views

Using stat_density2d with coord_map in ggplot2

In my example I am plotting a shapefile for all England & Wales, however I'm interested in the greater London area. If I allow ggplot to simply default and display the entire shapefile then the ...
4
votes
1answer
264 views

How to create cohesive Spatial Pixels from Spatial Points Dataset

I have a Spatial Point DF spo (covering an irregular shaped area of interest). The data are not on a regular grid due to crs transformation. My goal is a raster with predefined resolution and extent ...
3
votes
1answer
532 views

Counts the number of points in a polygon in R

I have two classes sharing the same CRS (Latitute and Longitude): bolognaQuartieriMap: a SpatialPolygonDataFrame containing data of a city boroughts. crashPoints: a SpatialPointsDataFrame containing ...
3
votes
1answer
122 views

How to create randomly points within polygons for each row of a dataframe matching a Polygon ID with R

My question is similar to this post, but because there are no "perfect" answer and above all no reproducible example I open this question. I have a "SpatialPolygonsDataFrame" and a data frame. Both ...
3
votes
3answers
854 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 ? ...
3
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2answers
711 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 ...
3
votes
1answer
4k views

Converting geographic coordinate system in R

I have points in geographic coordinate system and I wanted to convert them to swiss grid (CH1903+). Sample data: id lon lat 2 7.173500 45.86880 3 7.172540 45.86887 4 7.171636 ...
3
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3answers
1k views

How to extract the US from a North America Shapefile?

I have a north america shapefile, downloaded from ftp://ftp.epa.gov/wed/ecoregions/cec_na/NA_CEC_Eco_Level2.zip How can I get a new shapefile from this showing only us? Is there a way doing this in ...
3
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1answer
4k 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 ...
2
votes
1answer
102 views

Difference between raster() and readGDAL()?

I am new in working with rasters and after having trouble working with them i'd like to know the difference between those two import functions. for example i did this library(raster) ...
2
votes
1answer
380 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 ...
2
votes
2answers
173 views

Wrong projection high quality shapefile for the coastline of Helsinki region (Finland)

I did some spatial interpolations in R and I need a support for those. Looking for shapefiles online the best I could find was and it looks really horrible, the same area in ggplot looks like . I ...
2
votes
1answer
361 views

Convert multiple Shapefiles in Raster in R(and then plot it)

I'm trying to convert several shapefiles in rasters at the same time. I already was able to read the shapefiles by doing this: library(maptools) shps <- dir(getwd(), "*.shp") for (shp in shps) ...
2
votes
2answers
320 views

MODIS Level 1B batch process

I am a new MODIS Level 1B user. I have been using the MODIS Swath tool to process my images. However, I have over 1000 images to process. I was wondering if there a script available in IDL or R (very ...
1
vote
1answer
38 views

The stability of randomForest models after increasing predictor variables

With reference to the posts: Incorporating terrain data to predict canopy cover using randomForest in R and Random-Forest Classification of 10cm Imagery for species-distribution in R (no point-shapes) ...
1
vote
1answer
1k views

Plotting NetCDF file using lat and lon contained in variables

I am trying to plot this NetCDF file (and similar) as a 2d contour map. The file contains a single layer of one variable, "pr". The file has 413x229 X-Y pixel coordinates, and, stored inside the ...
1
vote
3answers
730 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 ...
1
vote
3answers
718 views

Merge Zip Codes to Create new sales Markets

Let me preface this question by saying I am very novice with respect to GIS. With this in mind, I am looking to merge zip codes into sales territories. Instead of plotting data by zip code, I want to ...
0
votes
1answer
803 views

r openproj to plot in open street map in a different projection

I am very new to geographic data, so I am sorry for the stupidity of the question. I need to plot some data that are in this projection EUREF_FIN_TM35FIN Projection: Transverse_Mercator ...
0
votes
2answers
1k 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 ...
11
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2answers
123 views

How does spatial polygon %over% polygon work to when aggregating values in r?

I'm working on an environmental epidemiology project where I have point exposures (~ 2,000 industrial hog operations - IHOs). These IHOs spray on nearby fields, but the feces water droplets and smell ...
9
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1answer
3k views

Converting point data into gridded dataframe for histogram analysis using R?

I am very new at using GIS data and only modestly experienced with R. I've been reading about how to analyze spatial data using the spatial-analyst.net PDF book, so I'm not completely lost, but I ...
8
votes
3answers
1k 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 ...
7
votes
1answer
2k views

How to rasterize SpatialPolygons in R?

I'm trying to extract the bathymetry values of my area of interest from a world bathymetry raster layer using the 'rasterize' function in the {sp} package. *Edits: I found the 'extract' function ...
6
votes
3answers
468 views

1km circles around lat-long-points in many places in world

I have hundreds of lat-long-points spread around the world, and must create circle-polygons around each of them, with radius exactly 1000 meters. I understand the points must first be projected from ...
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 ...
4
votes
1answer
523 views

Loading a multipoint shapefile in R

This issue has only been raised in the community once, two years ago, to the best of my knowledge. I think it's high time to raise the issue again! readOGR, from the rgdal package, cannot handle ...
4
votes
1answer
460 views

ggmap, ggimage… - Saving and loading maps in R

In my current R project I'm working with the ggmap package to download and display maps. What bothers me is that you need internet access to load maps from google etc. I'd like to load a map from the ...
4
votes
1answer
1k views

Zonal Statistics for Polygons with R

I'd like to do zonal statistics / terrain analysis with polygon overlays - I achieved to get min / max like so: library(raster) library(rgdal) alt <- getData('alt', country = "AT") gadm <- ...
3
votes
1answer
114 views

Plotting data without geographical coordinates besides the main map in ggplot2

I am trying to plot some data as a bubble chart on the world map using ggplot2 package in R. I am able to proceed as follows. # Load necessay packages library(ggplot2) library(rworldmap) ...
3
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0answers
86 views

kriging of compositional data (grain size)

I have posted this already in the GEONet Forum but without any suggestions, now I am hoping for some feedback here: I have a problem concerning interpolation of compositional data of grain sizes. I ...
3
votes
2answers
225 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
247 views

How to do regression analysis out-of-memory on a set of large rasters in R?

I am trying to do a regression analysis on a set of large rasters (254,004,000 cells each). Ultimately, I want to run something like the following (or a bit more complex, but let's start simple!): ...
3
votes
1answer
487 views

How to reproject a raster to Winkel Tripel projection?

I'm trying to project a raster map (in ASCII grid format) from longlat to the Winkel Tripel projection. But I'm running into errors, for instance gdalwarp won't accept the proj-string. $ gdalwarp ...
3
votes
2answers
897 views

Clip depth contour with spatial polygon

I need to somehow combine my Spatialpolygons with my depth contour, but not sure how do to so. Maybe create a SpatialPolygonsDataframe? This is what I've done so far: > class(subarea0) #This is ...
3
votes
1answer
549 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 ...
2
votes
2answers
125 views

What is the “best” way to automate the GIS slope and aspect algorithm?

I am currently obtaining slope and aspect of roofs using ArcGIS as follows: Mosaic several Lidar .asc files to new raster Extract by mask using Mastermap building outlines to get hold of just the ...
2
votes
1answer
312 views

How to read *.adf files into R?

I want to load .adf files into R. The data is from this page: http://www.fao.org/geonetwork/srv/en/metadata.show?id=14057 I tried the following code that I found after some research in the internet. ...
2
votes
0answers
32 views

How to measure similarity of approximately congruent polylines

My initial question was posted here. The answer of whuber provides a nice solution for the case when polylines are congruent. However, the problem is that my polylines are approximately congruent ...
2
votes
1answer
145 views

How to write every raster from a list of rasters?

I have created a list of rasters - "norm" and run a several loops. Now I would like to write every created raster from "norm" (containing 1 layer) into one raster, having its specific name. # I can ...
2
votes
1answer
170 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 ...
2
votes
1answer
236 views

plotting a map of north greenland in R

My knowledge in GIS and R is again tested when I want to map a small part of northern Greenland (called Washington Land) in R (and plot analysis data on top later). I've managed to plot it with ...
2
votes
2answers
690 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 ...
2
votes
1answer
2k 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 ...
2
votes
1answer
187 views

Several algorithms done for topographic correction => black spots - how to solve?

I have done several algorithms for topographic correction in R including simple cosine, Minnaert, SCS. The input data aspect and slope for the hillshade raster have correctly been done in radians. The ...
2
votes
2answers
2k views

Checking if Lng and Lat fall inside polygons from ESRI Shape file

I have two input files. First: CSV file with a list of points each defined with Lng, Lat, Name Second: ESRI Shape file defining a number of polygons I would like to determine for each point I have ...
2
votes
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, ...