polygon

I have created a google map using google map javascript API V3 . I am drawing number of zipcode polygons. The polygons are of different colors depending upon some condition. Now I want to draw straight lines/ hash marks inside some of the polygons depending upon certain criteria. How can we do it. Below is the code which I have written for drawing the polygons. {% if zip.zip_info.zip_polygon %} var path = [ {% for polycoord in zip.zip_info.zip_polygon %} new google.maps.LatLng({{polycoord.1}}, {{polycoord.0}}), {% endfor %} ]; var polygon_{{ forloop.counter }} = new google.maps.Polygon( { path

int pnpoly(int npol, float *xp, float *yp, float x, float y) { int i, j, c = 0; for (i = 0, j = npol-1; i < npol; j = i++) { if ((((yp[i] <= y) && (y < yp[j])) || ((yp[j] <= y) && (y < yp[i]))) && (x < (xp[j] - xp[i]) * (y - yp[i]) / (yp[j] - yp[i]) + xp[i])) c = !c; } return c; } This function checks if a point is within a polygon. How do I deal with a polygon coordinate that is negative? For example, float x[3] = { 0.16, 1.2, -10 }; float y[3] = { 1.8, 10, -5.5 }; I tried checking a valid point within the polygon and it returns 0. There are pretty good implementations from the iSurfer The

What is the best way to triangulate a polygon with Boost? I use Boost.polygon . My current algorithm: Compute a voronoï diagram from my polygon vertices. Create one directed polygon-edge for each cell-edge (this will create two directed polygon edge per cell-edge) Iterate over all created edges to create triangles (not trivial) Any better solution? Edit: I just realized that it is probably possible to walk through the cells in a special way to create the triangles directly (3 neighbor cells create a triangle). Giovanni Funchal The main idea is to iterate through the Voronoi vertices, and

I'm pretty sure that I'm doing multiple things wrong here but I'm not sure what... The table (minus a few fields): CREATE TABLE IF NOT EXISTS `stuff` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `lat` decimal(12,7) NOT NULL, `lon` decimal(12,7) NOT NULL, `location` point NOT NULL, UNIQUE KEY `id` (`id`), KEY `distance` (`distance`), KEY `lat` (`lat`), KEY `lon` (`lon`), SPATIAL KEY `location` (`location`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=5; The triggers to automatically set the location point: DROP TRIGGER IF EXISTS `stuff_insert_defaults`;

I'm drawing regions (using SqlGeometry / SqlGeography and translating them to the WPF LocationCollection equivalent) on the Bing Maps WPF Control and needed to label them. I got the labels drawn on the regions and attached them to the point found by STCentroid() . Of course as you imagine this is a problem with the 'U' or 'C' shaped regions where the centroid ends up outside the region, which makes the label incorrect. Is there a way using SqlGeometry / SqlGeography to find the "visual" center or perhaps find the largest circle that can fit in the shape and use that center? I've tried various

I have three points, for example: Start 194 171 Right 216 131 Left 216 203 I want to get all the points within that triangle. How would I do that efficiently? see z3nth10n's answer for better input validation Introduction: The general idea was to get the triangle's edges (y-Wise) for every x in it's range, and then you have all the y's that exist within the triangle for every single x, which with simple conversion turns into all points within the triangle. You can look at it as if you cut the triangle into stripes, each being of width 1. So for X=0, on the line between A and B, the Y is 6, and