2
votes
0answers
11 views

Error in unionSpatialPolygons using R

I am migrating from ArcMAP to opensource GIS. I've succesfully installed R and many packages in a Ubuntu 12.04 machine. I am used to linux and programming in C, but not to R and its syntax. I am ...
0
votes
0answers
11 views

How to get specific coordinate system to get arcGIS point shapefile in r?

I have a Point shapefile from arcGIS 10. I want to get it in r and also want to get it a specific predefined coordinate systen for my data. I can read the shapefile in R but summary in r Shows ...
2
votes
2answers
81 views

Extract Raster from Raster using Polygon shapefile in R

I am new to R and using the raster package. I have a problem extracting polygons from an existing raster file. If I use extract(raster, poly_shape) function on the raster it always creates a list ...
4
votes
0answers
24 views

Projecting polygon when calculating its area? [duplicate]

I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
2
votes
1answer
41 views

Compute the area of a given polygon (in vector format) lying between specified lines of latitude

I have species distributions (in vector format) and I would like to calculate how much of the area for a given species distribution is within certain lines of latitude, such as temperate and tropic ...
4
votes
2answers
87 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 ...
1
vote
1answer
88 views

Convert from eastings and northings to latitude and longitude without ArcGIS

I am not a GIS user, but I was given some shapefiles to work with. I do not have ArcGIS or any other GIS tool, but I do have Matlab with the mapping toolbox and R. From what I can tell, the data is ...
3
votes
2answers
123 views

How can I create a choropleth from the 2010 census ZCTA shapefile using R and ggplot2?

I have created state and county choropleths in R using ggplot2. The method I have used for this came from Winston Chang's "R Graphics Cookbook". For those choropleths the map was already represented ...
2
votes
1answer
57 views

shape file for linked micromap not working

I am trying to replicate the example provided in the micromap R package of a linked map with the poverty rate for the 50 US states. I am trying to achieve the same results with a Shapefile from ...
3
votes
1answer
173 views

remove land area from marine region polygons

In my pursuit to merge multiple polygons for the purpose of calculating the surface area of marine species distributions, using shapefiles from Marineregions, I am now trying to remove potential land ...
5
votes
4answers
180 views

Calculating percent cover from shapefiles

I normally do not work with shapefiles, so I am a bit lost here. I have two shapefiles each with multiple objects. The first is a set of 32 polygons (each one is a plot). The second shapefile has ...
2
votes
1answer
66 views

Axis of rendered shape files not showing numbers that are latitude and longitude

I am using rgdal to render some shape file. The first is a set of building zones from NYC Open Data. The second is the NYC coast line from OSM. The Zone files seems to generally render an X axis ...
1
vote
2answers
210 views

unionize intersections of merged polygons

[Updated quesion] I am using the following code to merged polygons from shapefiles for the purpose of calculating the surface area; library(maptools) library(rgdal) library(rgeos) #enter slots, ...
3
votes
2answers
160 views

Convert polyline shapefile to points 1m apart and add xy coords in R

I have a table with xy coordinates in R and the following packages loaded: spatstat, raster, rgdal, sp and zoo. I do know how to use this to make a point shapefile, a line shapefile that goes through ...
1
vote
2answers
221 views

Calculate distance in kilometers between two points

I have a few questions regarding the calculation of the distance between 2 postal codes. Take a look at the following code. ### # load the different packages we need ### require("rgdal") ...
0
votes
1answer
60 views

How can I export a point shapefile from ArcGIS to R

I am having several problems in exporting my point shapefile from ArcGIS 10 to R. I tried to save the shapefile as a CSV, but R reads all in one row; somebody in another question answered to use ...
1
vote
1answer
224 views

Can't plot polygons with R and ggplot2

I am new to shapefiles so I maybe ask some stupid questions, sorry. I want to plot a map of my region, with colour filled polygons using R. I have downloaded municipal (lines) and province (polygons) ...
8
votes
2answers
235 views

Simple way to detect/select border polygons of a shapefile

I am looking for a simple way to detect/select border polygons of a shapefile. Border polygons are here polygons that are not completely surrounded by other polygons i.e. polygons located at the ...
0
votes
0answers
24 views

calculating mean and standard deviation for raster values using whole pixels within a polygon [duplicate]

i have a raster image and a corresponding shape file. i would like to calculate the statistics of the values within polygons which have a common attribute but only using pixels which are fully ...
0
votes
0answers
93 views

why readOGR() is not reading projection information from .spj - r

0 down vote favorite I successfully import a polygon shapefile with readOGR, however the information in the .prj file is not being imported. test class : SpatialPolygonsDataFrame nfeatures : 19407 ...
3
votes
3answers
145 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 ...
4
votes
1answer
172 views

How to join data from NHGIS to make choropleth maps in R/ggplot2?

I have downloaded shapefiles of county/state boundaries and census data keyed to those shapefiles from the NHGIS. Both the shapefiles and the census data have a GISJOIN column to be used for merging ...
4
votes
2answers
269 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 ...
4
votes
1answer
930 views

R - Plotting shapefile with geographical (raster) data

Over the last few days I have been trying to plot a shapefile over data loaded into a data.frame within R. It should be a view of radar precipitation with an overlay of the country borders from a ...
0
votes
0answers
156 views

Drawing a map of a country with specific boundaries/zones using postcodes latitude and longitude

I'm quite new in geocoding - it has been fun! My project is to draw Australia with specific boundaries/zones using R program. I was able to successfully upload a shapefile of Australia in R program, ...
0
votes
1answer
39 views

Error in performing transect in ambur R?

I'm trying to filter a transect, window size is 5 and filter individual baselines is set to 0. I select the transect shapefile, then the inner baseline shapefile and it gives me this error. Error in ...
0
votes
0answers
138 views

R program and shape files

I have an R program that sketched a country. This is done by reading a shape file that contains the coordinate of a country (latitude and longitude). How do I export the data from shape file into ...
1
vote
0answers
32 views

How to load or query data directly to R from a PostGIS database using RPostgreSQL and rgdal [duplicate]

Is it possible to load/query a shapefile to R, which is stored in a postgres/postgis database? I've built up a connection to my postgres database via DBI, RPostgreSQL and I want to make some ...
0
votes
0answers
76 views

Why does a shapfile shift after transformation?

I have a shapefile created in the raster package (ER_14.3_2000_poly). > #read in a raster file > ER_14.3_2000<-raster('E:/Ecoregions Models/Outputs/ER_14.3/ER_14.3_ConsensusMap3.asc') > ...
3
votes
1answer
370 views

Setting extent and geographic projection in R

I have a raster and a shapefile that I am attempting to view and process in R. The shape file "ER_11.1" has the following specs: > ER_11.1 class : SpatialPolygonsDataFrame nfeatures : 22 ...
1
vote
2answers
1k views

Choosing the correct value for proj4string for shape file reading in R “MapTools”

I am having a shape file of polygons and another CSV file which contains a list of points as (Lat, Lng) pairs.. I want to check for each (lat, lng) pair from the CSV file which polygon does it fall ...
1
vote
2answers
291 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 ...
0
votes
2answers
391 views

How to add a field to a shapefile using R

This question is trying to make sense of a post that already exists that looks good, but is failing in practice. The second ranked answer uses the foreign package to read a shapefile attribute table ...
5
votes
1answer
1k 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 ...
2
votes
2answers
451 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 ...
2
votes
5answers
721 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 ...
3
votes
2answers
258 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
252 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
0answers
49 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. ...
7
votes
1answer
749 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 ...
3
votes
0answers
455 views

How to Export a Shapefile as KML Using R

All, I have exported an ESRI shapefile (polygon) to KML using R, but the resulting layer shows only the outer extent of the polygon. How can I fill in the area with a color? Any help is greatly ...
14
votes
2answers
2k views

Using R to calculate the area of multiple polygons on a map that intersect with another overlaid polygon

I have a shapefile downloaded from the Ordnance Survey that gives electoral ward (division) boundaries for a county of the United Kingdom. I have successfully used R to load the shapefile and plotted ...
1
vote
3answers
388 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 ...
4
votes
2answers
382 views

What is the cause of 'tearing' of polygons (artifacts) using R, ggplot and geom_polygon?

Thanks to the answer given in this question I have been able to subset and draw a map of electoral divisions in part of the UK, in this case Pembrokeshire. The resulting data frame is large and ...
7
votes
1answer
677 views

How can I use fortify() to create a filtered R data frame from a shape file?

I am in the process of building a ggplot choropleth map of population in administrative areas in Wales. I have downloaded the Boundary-Line data from the Ordnance Survey and extracted what seems to be ...
3
votes
1answer
256 views

How to stop writeOGR from abbreviating Field Names when using “ESRI Shapefile” driver

I'm currently using the following script to add some attribute data from a table to lots of individual shapefiles: library(rgdal) specieslist <- read.csv("SpeciesList1.txt", header=F) attdata ...
5
votes
2answers
987 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, ...
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, ...
1
vote
1answer
2k 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 ...
2
votes
2answers
172 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 <- ...