Statistical computing language and software environment.
2
votes
2answers
290 views
How do I use ranges for raster colour map in QGIS
I have a raster layer in GeoTIFF format, with continuous data values between -1 and +1. For the colour map, I would like...
>0 to be green
= 0 to be grey
<0 to -0.25 to be pink
<-0.25 to ...
9
votes
1answer
258 views
How to visualize azimuthal data with uncertainties?
I am trying to make a figure showing azimuthal data with a different range of uncertainties at each point. This oldschool figure from a 1991 paper captures the "bowtie plot" idea that I'm aiming for:
...
5
votes
4answers
1k views
Dissolve ploygons in QGIS or Grass to new polygons of defined population sizes
I have a shapefile with 3800 polygons representing the smallest administrative areas in Ireland. Many of these, in rural areas, have tiny populations, under 100 people. In urban areas, all would have ...
12
votes
1answer
324 views
How to generalize SpatialPolygons and conserving topology in R?
I would like to generalize a SpatialPolygonsDataFrame in R to make plotting more efficient. The polygons I have result in huge pdf plots that are slow to load and hard to integrate into a document.
...
10
votes
3answers
2k views
How to cluster spatial data in R?
I am very new to R, so please bear with me : >
I have bunch of data points with latitude and longitude. I want to use R to cluster them based on their distance.
I have already taken a look at this ...
4
votes
2answers
294 views
How to calculate area of 1 x 1 degree cells in a raster
I have a simple array (not geo-referenced in any way) in Matlab (which is not a language I know a huge amount about...so I can export it to other languages if needed) which has the dimensions 180 x ...
1
vote
1answer
303 views
rpy2 installation on Mac OSX
I'm desperatly trying and retrying to install rpy2 on my Mac OS 10.6 in order to run SDA4PP plugin on QGIS.
My version of R is 2.14.0 and it was obviously compiled with the option --enable-R-shlib ...
7
votes
2answers
576 views
How to Find the Average Raster Value of an area defined by a shapefile using R?
I have a set of raster images which represent a specific month over the years, and I want to make a timeline of the average values of an area using a shapefile.
How do I extract the values from the ...
5
votes
2answers
960 views
R spplot tutorials
I'm in need of some tutorials/books/other training materials which cover how to use the spplot function in the sp package in R properly.
As with many of these functions, it seems very powerful, but ...
14
votes
3answers
512 views
Ecological geospatial conundrum
I am looking for a different, more elegant solution to a spatial statistics problem. Raw data consists of an x-y coordinate for each individual tree (i.e. converted to a point .shp file). Although ...
2
votes
2answers
120 views
Go from multiple rasters to R compatible table
I have a set of geocoded, pixel-aligned rasters which I would like to use in a model in R. I would like to produce a table of data that can be imported to R, in which there are as many columns as ...
0
votes
0answers
130 views
Plot data on a map [closed]
I've a data set contains three variables: longitude, latitude, population (in USA). I need to plot these data on a map. I use the following code (it works fine):
map("state", xlim = range(lon), ylim ...
16
votes
6answers
510 views
What are sources for current geo-statistical analysis classes/events: open or proprietary
I am keenly interested in geo statistics (and many other words with 3 t's :).
I am not very programatically inclined but have been following several lists with this theme.
One being the R filter on ...
7
votes
4answers
3k views
How can I export raster data from Arcmap to an R *.grd file format?
I want to work with raster data in R, but I have problems exporting my raster dataset from ArcMap. By "export data"/GRID I get a file with an *.aux extension. What I need is *.grd.
Can anybody help ...
2
votes
1answer
232 views
Recreating A Lat/Long Grid Using a Specified Formula
I'm trying to recreate the Gridded Mercury emissions 2000 (0.5 x 0.5 degree grid) designed by the Arctic Monitoring and Assessment Programme. The file is in ASCII format, but without any coordinates. ...
3
votes
2answers
427 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 ...
5
votes
1answer
596 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 ...
13
votes
1answer
691 views
Robust alternatives to Moran's I
Moran’s I, a measure of spatial autocorrelation, is not a particularly robust statistic (it can be sensitive to skewed distributions of the spatial data attributes).
What are some more robust ...
6
votes
1answer
1k views
How to convert point data into a gridded dataframe for histogram analysis?
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 ...
5
votes
1answer
163 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 ...
3
votes
1answer
855 views
How to intersect lines and polygons in R?
Following on from an answer about intersecting polygons with lines to chop up a polygon into smaller polygon units (in QGIS), I wanted to try the same thing in R. However, I cannot seem to find a ...
3
votes
1answer
282 views
Where can I download a xyz bathymetry file of the Northwest Atlantic?
I'm looking to download the bathymetry of the Northwest Atlantic ocean as a txt file or any other file format that I can easily upload and use in R.
I once used the Global topography - Scripps ...
4
votes
2answers
662 views
Create a raster with georeferenced information in R
Referring to my previous question, how do I "geocode"/convert - using R - a generated raster image to a format that can be shown as a layer on a map? In short, I'm aiming to recreate the results of ...
1
vote
1answer
174 views
Get raster field names in R
Does anyone know how I can extract the raster field names (VALUE, COUNT and other existing field names on a categorical raster file) in R?
I am using the raster package to load the raster files.
1
vote
0answers
216 views
How to extract polygon means from raster data and match the mean to the original attributes from the shapefile? [closed]
My polygons (p) was read from a shapefile (shp). I know that I can extract the polygon means by:
means <- extract (r, p, fun="mean")
My question is how I can match each mean with the ...
1
vote
2answers
103 views
Looking for R-compatible geospatial datasets
I try to work with geospatial data of North America.
Is there any high-resolution map material available for/in R?
2
votes
3answers
797 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 ...
4
votes
2answers
573 views
How to draw a point at an exact location with spplot?
I imported a Shapefile holding a quite detailed world map from: http://www.diva-gis.org
library(sp)
library(rgdal)
world = readOGR('./countries_shp/', 'countries')
Using R with the sp-Packages, ...
2
votes
1answer
1k views
How to convert decimal degrees units to km in R?
I am trying to figure out how I can transform my unit of length from decimal degree to km when I import the following simple ArcGIS polygon shape. Ultimately, I would like to have this information ...
4
votes
0answers
405 views
How to get rpy2 for QGIS on OSX?
I am a new QGIS user, have installed QGIS on a Mac running Snow Leopard OSX 10.6.8 following all the instructions. QGIS seems to work well for everything other than when I boot up I get the message
...
1
vote
0answers
151 views
How to load big ASCII rasters in Revolution R?
Is there anyone in this site using Revolution R with big spatial data ?
I am trying to load raster files (ascii format) into revolution r using the xdf format, with no luck.
Did anyone tried this ...
0
votes
0answers
109 views
Making a Bridge Classification tool in GRASS GIS
I'm working on a tool for classifying bridges with GRASS. I have been using examples online but I've come to a standstill as how to actually make this tool in GRASS. I have my raster of my area and ...
2
votes
1answer
179 views
Generic comparison for kriging in geoR and ArcGIS
I am going to do a project based on kriging. The targeted area would be as big as United States and my grid would be 10km*10km. I am wondering the differences of efficiencies for the methods ...
10
votes
1answer
2k views
How can I convert data in the form of lat, lon, value into a raster file using R?
I have a data set of values over a km grid in the continental U.S. The columns are "latitude", "longitude", and "observation", e.g.:
"lat" "lon" "yield"
25.567 -120.347 3.6
25.832 ...
2
votes
2answers
331 views
ArcGIS Desktop 10 ModelBuilder iterations
Hi all
I have some home range estimates for fish that I made using the adehabitat pkg in R. However, a lot of them overlap land, so I need to subtract the area where they overlap with land ...
6
votes
1answer
2k views
GIS, R and shapefiles
I have some data that encodes locations in certain countries, such as the US and China, that I would like to map. The data includes location name in Latin, extended Latin and other scripts (Japanese, ...
2
votes
1answer
477 views
Conversion of raster features to polylines: skeletonization?
I would like to identify linear features, such as roads and rivers, on raster maps and convert them to a linear vector features (i.e. polylines). I typically use R as my primary GIS, and have posed ...
1
vote
1answer
815 views
merging 2 polygon adjacent to each other using R
I have several shp files which are the components (or tiles) of a map, I have joint all these tiles together to have a large shp file. Then I realized some of the polygon is now splitted into 2 ...
14
votes
1answer
531 views
Monte Carlo simulation using QGIS and pgRouting on optimal sidewalk construction
I am new to spatial analysis and would appreciate some general direction on a project I am attempting, outlined below (I am starting from scratch).
GOAL: To find the best locations to install 2000 ...
2
votes
2answers
139 views
Color a layer of the map based on the location of dots on another layer
Thanks for helping me in GIS 101 Problem #2, now I have followup questions:
I created a map as below:
The map is created using the following script:
ct <- ...
4
votes
1answer
1k views
How to plot points on maps using ggplot2 and R?
Thanks for help me in GIS 101 Problem #1, now I have geocoded a few hospital in Connecticut using google map, I have able to visualize them in QGIS, now I am trying to do it in R.
ct <- ...
2
votes
1answer
525 views
How to select a Subset of PolySet data in R?
I am using the PBSmapping package in R to model data from diva-gis. I can read in the shapefiles and plot them with no issue.
library(PBSmapping)
df = importShapefile("/path/df.shp")
plotPolys(df)
...
1
vote
2answers
267 views
NA values in dbf when exporting shapefile from R with writeOGR?
I´m writing an esri shapefile from R (2.14.1) on windows, using writeOGR in the rgdal package, in the resulting dbf file, NA values in the spatialpointdataframe (in numeric columns) are not translated ...
9
votes
1answer
223 views
How to find the most spread out locations?
Probably a very simple question. I have a list of about a thousand potential geographical locations (lat lon), and of those I need to select the 200 locations that are "most spread out". I think that ...
3
votes
1answer
252 views
Spatial Interpolation Methods like PRISM
I am looking for some kind of software (free software) that allows me to make an interpolation like PRISM software.
The interpolation used in PRISM is a
local regression and accounts for ...
6
votes
3answers
400 views
Identification of consecutive points within a specified buffer
I have a point file, hourly relocations of an animal, and I want to be able to place a buffer around each point and calculate the number of subsequent points which are within the buffer zone. I am ...
2
votes
1answer
894 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 ...
4
votes
1answer
1k views
Spatial distance join between polygon and points using R?
I'm figuring out how to do a Intersection (Spatial Join) between point and polygons from shapefiles. My idea is to get the closest points and those points that match completely inside the polygons. In ...
6
votes
2answers
550 views
creating a raster of the residuals of a regression between two rasters
I am trying to create a raster of the residuals of a regression between two rasters. i.e. I would like to carry out a regression of one raster against another of the same extent and plot the residual ...
2
votes
2answers
1k views
How to overlay map layers (shp and csv) in R?
This is a crosspost from stackoverflow. I know very little about GIS software and am doing all my mapping in R. Apologies in advance if this is too basic question. Let's say I have two shapefiles from ...
