# Tagged Questions

1answer
81 views

### Automating Intersect between two polygon layers

I have a spreadsheet that has county-level occurrences of around 1000 species within the US in the column headings (Species State County). Thus, for some counties there may be multiple species. I ...
2answers
259 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, ...
2answers
137 views

### Is there a way to speed up gIntersections for large spatial objects?

I'm attempting to perform a gIntersection of a big grid on a shapefile for country boundaries, so that I can calculate the % area of each grid cell that lies within the country. It takes a few seconds ...
1answer
445 views

### How to split a polygon using R

I have an irregular polygon which is a spatial object. I want to divide it into multiple polygons (say, n=25) with equal height. To show how I want to divide it, I've plotted grids on the ...
0answers
175 views

### Cut polygon and retain data

I have these two polygons: library(sp); library(rgeos); library(maptools) coords1 <- matrix(c(-1.841960, -1.823464, -1.838623, -1.841960, 55.663696, 55.659178, 55.650841, ...
1answer
239 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 ...
1answer
431 views

### Intersection between two SpatialPolygonsDataFrame using gIntersection function in R

I want to select a subset of my map (a SpatialPolygonsDataFrame) to create a new vector map = part of the initial map included inside a given polygon (eventually, inside several polygons). I have a ...
2answers
431 views

### How to single out country data from a world data map?

Say that i have two "data sources"; A global map of average wind speeds, A shape file (or similar information) of all country borders in the world. How do i combine these two sources and extract ...
0answers
348 views

### Rgeos drops associated values when intersecting polygons

I am trying to intersect two SpatialPolygonsDataFrames and get a SpatialPolygonsDataFrame as the result. Unfortunately, using the gIntersection function from rgeos (which works impressively quickly ...
2answers
288 views

### No intersection found between polygons I know intersect!

I'm using two geographies: one is made up of small areas (about 2200), the other large areas (about 70). Both cover all of Australia, and the small areas are not necessarily nested inside large areas. ...