polygon

I'm studying d3.js force chart and I have a question. Is it possible to make a force chart inside a triangle with some coordinates? Here is my code: var width = 500; var height = 500; //margin var marginLeft = 10; var marginTop = 10; var marginRight = 10; var marginBottom = 10; var margin = { left: marginLeft , top: marginTop, right: marginRight, bottom: marginBottom}; //size of canvas var innerWidth = width - margin.left - margin.right; var innerHeight = height - margin.top - margin.bottom; var radius = 10; var svg = d3.select(".forcechart").append("svg") .attr("width", width) .attr("height",

I am trying to compute a polygon that surrounds a line connecting multiple points (e.g. a GPX track). The image below shows an example with the track as red line and the desired polygon in blue. As simplification the red points are denoted by x and y - not by latitude/longitude. How do I compute such an environment (light blue polygon) if I only have the list of the three points specifying the path? Partial solutions (e.g. for only two points) or hints about mathematical libraries (in Java) that provide algorithms for such a computation would also bring me one step forward. Further assumptions

I'm working with the new Entity-Framework 5 using the Spatial data type DbGeography as part of my model for storing in one instance, a POINT and in another instance a POLYGON. When setting the value of my POLYGON all saves with no error however this is only the case if I draw the Polygon on the map in a clockwise order. If I draw the POLGON in an anti-clockwise direction I get an error the the sql level indicating that the data is an invalid geography type. Now after doing my own research into the problem, it appears to stem from the geography data type being quite strict in terms of a

I want a plot of an area, such as Latin America, using the world shape file from IPUMSI... https://international.ipums.org/international/resources/gis/IPUMSI_world.zip ... I will add some more IPUMS districts later so I really want to use this as my template layer. I having difficulty with the plot when I add limits through coord_map in ggplot2. The initial spatial file looks alright library("ggplot2") library("raster") sd0 <- readShapePoly("./IPUMSI_world.shp") df0 <- fortify(sd0) ggplot(data = df0, mapping = aes(x = long, y = lat, group = group)) + geom_polygon(fill = "black", colour =

I currrently have the code included below to draw this: What I am trying to do is get the outline for each of the groups to follow all of the points in each group - rather than skip some of them as it currently does. In addition I would want each outline to have a semi-transparent fill. Thanks for any help. library(ggplot2) library(reshape) library(car) G1 <- 1:10 G2 <- 11:20 G3 <- 21:30 G4 <- 31:35 G5 <- 36:41 sdata <- read.csv("http://dl.dropbox.com/u/58164604/sdata.csv", stringsAsFactors = FALSE) pdata<-melt(sdata, id.vars="Var") VarArea <- data.frame(unique(pdata$Var)) VarFinalMin <-c()

For example we have two rectangles and they overlap. I want to get the exact range of the union of them. What is a good way to compute this? These are the two overlapping rectangles. Suppose the cords of vertices are all known: How can I compute the cords of the vertices of their union polygon? And what if I have more than two rectangles? There exists a Line Sweep Algorithm to calculate area of union of n rectangles. Refer the link for details of the algorithm. As said in article, there exist a boolean array implementation in O(N^2) time. Using the right data structure (balanced binary search