point-in-polygon

We need to figure out a quick and fairly accurate method for point-in-polygon for lat/long values and polygons over google maps. After some research - came across some posts about mysql geometric extensions, and did implement that too - SELECT id, Contains( PolyFromText( 'POLYGON(".$polygonpath.")' ) , PointFromText( concat( \"POINT(\", latitude, \" \", longitude, \")\" ) ) ) AS CONTAINS FROM tbl_points That did not however work with polygons made up of a large number of points :( After some more research - came across a standard algorithm called the Ray-casting algorithm but before trying

I am using python and I have defined the latitudes and longitudes (in degrees) of a polygon on the map. My goal is to check if a generic point P of coordinates x,y falls within such polygon. I would like therefore to have a function that allows me to check such condition and return True or False if the point is inside or outside the polygon. In this example the point is outside so the result would be False Question : Is there a library/package that allows to reach my goal? if yes which one do you recommend? would you be able to give a small example on how to use it? Here is the code I have

I am using the Google Maps API on Android to create a puzzle. This link contains the data I used to draw African countries: World countries coordinates . When the user clicks on the map, a test is done to check whether it was in the right country or not. point inside right country: the right country is colored in green point inside another known country: the current country is colored in red The code below iterates the list of African countries (a country may contain multiple polygons) to find the one that contains the clicked point and compare it with the right country. mMap

Is it possible to determine whether a GeoJSON point at a given lat,lon lies within a given GeoJSON polygon using only JavaScript (either through d3, topojson, or any other way)? For example, I can draw a map showing countries in the UK based on the tutorial here . I then have a some points which have coordinates but no indication as to which country they lie within. I would like to display a total point count for each country. Can I work out which country contains each point in the browser, or do I need to preprocess my point data on the server using PostGIS or similar? Seems like d3 has you

I have been trying to figure out how to write a simple program to compute the x,y points for creating a regular polygon of n sides. Can someone give me some code examples that don't use preexisting functions that draw polygons? I want to understand the process, which I assume is something like this: pick an angle to start from a radius and a center point somehow calculate the x,y position at that distance from the center(how?) divide 360 by the number of sides, move that distance and draw the next line from the first x,y point continue until the angle=360 divided by that number. Assuming that