Flex :: Calculating The Area Of A Polygon When The Polygon's Points Are Lat Longs: Which Function Is More Accurate?
Jul 28, 2010
I'm trying to find a way to calculate the area of a polygon using lat long coordinates in a Flex 3 site. Hong007 on Google Maps for Flash group was cool enough to post the following function:
[Code]...
I was also playing around with the area calculator at [URL]. These functions produce slightly different results. I'm trying to figure out which one is more accurate. It seems that hong007's function produces results that are on average slightly larger than freemaptools' function. However, I don't know which one is more accurate.
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May 20, 2011
I have been looking at posts about determining if a point lies within a polygon or not and the answers are either too vague, abstract, or complex for me. So I am going to try to ask my question specific to what I need to do.I have a set of points that describe a non-straight line (sometimes a closed polygon). I have a rectangular "view" region. I need to determine as efficiently as possible whether any of the line segments (or polygon borders) pass through the view region.
I can't simply test each point to see if it lies within the view region. It is possible for a segment to pass through the region without any point actually inside the region (ie the line is drawn across the region).Here is an example of what I want to determine (red means the function should return true for the set of points, blue means it should return false, example uses straight lines and rectangles because I am not an artist).
Another condition I want to be able to account for (though the method/function may be a separate one), is to determine not just whether a polygon's border passes through the rectangular region, but whether the region is entirely encompassed by the polygon. The nuance here is that in the situation first described above, if I am only concerned with drawing borders, the method should return false. But in the situation described here, if I need to fill the polygon region then I need the function to return true. I currently do not need to worry about testing "donut" shaped polygons
Here is an example illustrating the nuance (the red rectangle does not have a single vertex or border segment passing through the on-screen region, but it should still be considered on-screen):For the "does any line segment or polygon border pass through or lie on screen?" problem I know I can come up with a solution (albeit perhaps not an efficient one). Even though it is more verbose, the conditions are clear to me. But the second "is polygon region on screen?"PS I have a function for determining line intersection, but it seems like overkill to use it to compare each segment to each side of the on-screen region because the on-screen region is ALWAYS a plain [0, 0, width, height] rectangle.
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Jul 1, 2011
if there is a way to get by Actionscript the position of points in a polygon made using Pen Tool?
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Feb 5, 2009
I'm working on a pathfinding algorithim using A* and using irregular polygon shapes as obstacles rather than a grid. I don't fancy plugging in all the points and links by hand and was wondering if there was some way I could just get them from a Sprite or MovieClip?
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Dec 29, 2011
I'm trying to create a function that draws a polygon with two parameters that are: number of sides and length of sides. You would input a number for side length and a number for the number of sides. Then it would draw the side length, then turn at a angle based on the number of sides, then draw side length again... until it has finished drawing the polygon based on the number of sides that were put in.
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Jun 11, 2010
I wish to develop a software for 3D object compression (by polygon reduction) in flex using papervision 3D.
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Jun 11, 2010
I wish to develop a softare for 3D object compression (by polygon reduction) in flex using papervision 3D. Could you please suggest me an efficient algorithm for the same?
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Aug 10, 2011
I want to create an app for drawing polygons with a variable number of vertices, with the following requirements (very similar to a vector drawing program such as Adobe Illustrator):
-each click of the mouse on the stage sets a vertice (e.g. draws a small square or circle to mark the spot), which draws a line to (e.g. LineTo) the prior vertice, and so on, until the final click, if close enough to the first vertice, will complete and close the polygon
-each of the vertices of the completed polygon should be draggable with the mouse, so that that completed (or partially completed) polygon maintains its integrity while changing shape, that is, so the user can modify the polygon shape without having to redraw it. it's the second step I'm having the most difficulty with...in general terms, how would I implement this? Perhaps each vertice should be a draggable Sprite containing a small square or circle graphic?
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Jun 30, 2009
I'm trying to figure out how to draw a polygon from an array. I've found a few examples, one which the author says works, but am not getting anything to appear. I've traced the array (it's registering) and am getting no errors.
Code:
//called from constructor
polygon(thisArray);
[code].....
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Mar 20, 2011
I know that I can collect the pixels of a rectangular area within a Bitmap using getPixels(), but is there a way to collect the pixels of a polygonal area with more than 4 points? Or at least determine whether a particular pixel lies within a polygonal area of a Bitmap?
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Oct 8, 2009
I'm building a map editor for a project and need to draw a hexagon and fill it with a solid color. I have the shape correct but for the life of me can't figure out how to fill it. I suspect it may be due to whether the thing is a Shape, Sprite or UIComponent. Here is what I have for the polygon itself:
import com.Polygon;
import mx.core.UIComponent;
public class greenFillOne extends UIComponent {
[Code].....
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Mar 16, 2010
I'm using a game physics library (Box2D) which only supports convex polygon shapes. However, I'd like the level builder to be able to just specify concave polygons without having to worry about that. So, how can I automatically break apart a concave polygon into convex ones (or even all triangles). Speed would be cool, but ease of implementation is more important. The breaking apart will only be done on game initialization.
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May 9, 2011
I am creating a project in Flash using the Google Maps API and docs. I'm trying to add a marker to the map, which is draggable but I don't want it to look like the standard Google Maps bubble-style marker. Is it possible to have a custom polygon or image but still keep the draggability?
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Dec 12, 2011
I'm making an app in Flash, and I want to define some polygons which I can bind hover events to to add annotations to an image.I can create these normally in Flash, but I want to load some external data, a list of coordinates, and create the polygons with ActionScript.
Obviously they're just hotspots, so I want them to be invisible, but searching for my problem only shows results for drawing polygons from coordinates using the graphics property of a movieclip.The data doesn't ever change, so it would be possible to just draw all the polygons manually with the pen tool, but the data is being used elsewhere, so it would be much easier to maintain if I could add new zones just by updating the text file.
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Aug 25, 2011
I'm working on a method to do more accurate path finding for a special project. I haven't yet found any sources on this so i have to write it myself.
The idea was to use a polygon mesh, draw waypoints between all points then discard ways intersecting with a polygon. After that use dijkstra's algorithm to find the closest path.
Detecting whether a line intersects with a polygon mesh is the tricky part. I haven't yet come up with any viable solution that is fast. how i can determine whether a waypoint travels through a polygon?
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May 25, 2011
I am creating a game where I have some red balls on the screen and some blue balls on the screen and I would like to draw a polygon around all balls of the same color and have this polygon automatically fill as soon as the polygon shape is closed. How to achieve this as I haven't really done much with the drawing API before. My current code will allow me to draw a polygon and for it to fill when I release the mouse but what I would like it to do is automatically fill as soon as the shape is closed.
Here is my code so far
Code:
var graphix = new MovieClip();
addChild(graphix);
var points:Array = [];
stage.addEventListener(MouseEvent.MOUSE_DOWN, startDrawing);
[Code] .....
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Mar 18, 2011
When I double click to close the selection, the marquee vanishes instead of closing the selection. Yes, I double click on the starting point.Here's what the manual proclaims (step 4):
Draw a straight-edged selection area1 Select the Lasso tools Polygon Mode modifier in the options area of the Tools panel.2 Click to set the starting point.3 Position the pointer where you want the first line to end, and click. Continue setting end points for additional line segments.4 To close the selection area, double-click.
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Dec 27, 2011
I am developing a game for mobile in AIR (as3). I have created some bots for this game that initially just wander around. But when a bonus enters the stage, they have to move to the bonus.The detection of a new bonus and moving of the bots works fine, but there is something wrong with the manipulation when a new bonus enters the stage.Basically, this is how it works (or I try to make it work):My bot moves along with his rotation as a parameter. (works fine)
private function moveToNextLocation():void
{
var angle:Number = _rotation * 0.0174532925; // 1 degree = 0.0174532925 radians
var speedX:Number = Math.sin(angle) * _speed;
[code]....
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Oct 3, 2011
I have been tasked with trying to create a drawing tool that draws dotted lines as you drag the mouse across the stage. I can easily capture the points on MouseEvent.MOUSE_MOVE and store them in a vector and then draw the points as dots:
The problem is that I need to calculate evenly distributed points on an ever growing Vector of points so I can only draw the line between say every 5th point (say using modulus). I have been battling away with Bezier curve equations both Quadratic and Cubic but still can't quite figure out how to convert my Vector of points into an evenly distributed Vector of Points without sucking the life from the CPU.
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Dec 23, 2009
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Aug 22, 2004
i got a problem with a nice skew function From Ericlin of URL...[code]i have prepared a small and plain .fla for you so you can check it out right here, its also attached to the posting (Flash MX 2004 File but should be ok for earlier versions?):url...while the borders of isometric walls are still exactly vertical (90 deg) the function is producing lines which are very slightly skew. might be something like 90.1 deg... but this inaccurancy produces ugly gaps between walls i put together later.This function is maybe not accurate enough, maybe to accurate, i am not sure. But i need probably some rounding in there but i dont know where, really (is that a wonder? look at the script! ;))when you zoom in and look at the "orientation bar" (thick dark blue bar), you will notice that there is a very small gap on the top right corner but its bigger on the bottom right corner of the wall texture.
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Aug 22, 2004
got a problem with a nice skew function From Ericlin of Here is the content of the original Actionscript Function:
PHP Code:
function skewObj (obj, mcW, mcH, pt0, ptH, ptW)function distance (pt1, pt2) var dy = pt2.y-pt1.y; pt2.x-
[code].....
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Jan 4, 2004
I have a movieClip, with other movieClips inside of it, objects that I want when hit to lose points. But when I have the movieClips inside that one, it just has a giant "boundry box". I want the points to go down when you hitting only one of those items, intead it just goes does throughout the entire thing.
There is no way for me to scroll all those objects across the screen without either making a tween on the main timeline for each object (almost 20), or somehow making a giant movieClip scroll all of them all the way across, bypassing the first boundry box, and acknowledging the movieClips.
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Mar 27, 2009
How to calculate the area of a triangle giving 3 (X, Y) points?
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Dec 7, 2009
I'm trying to sync animation to music at a specific BPM. I've tried using the Timer but it isn't accurate when dealing with small intervals in milliseconds. I did some reading and found an alternate method that uses a small silent audio file and the SOUND_COMPLETE event as a Timer.[code]...
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Mar 17, 2010
For a schoolassigment me and some buddies of mine are creating an application that is showing many similarities with the C-Mon & Kypski musicvideo on [URL]. The application is being developed in Flex.
We want to get a random point of a clip, let it pause so a user can mimic the pose and make a snapshot out of it.
What i managed to do is get a random point of the movie. I did this by getting a random value between 0 and de total duration of the movie.
But what i didn't managed to do is let the screen pause on every 24st of a frame. As the movie concist out of 24FPS. It looks like the the random value of the movie that is being requested is being rounded by the movie itself. As example: There appears to be no difference between the frames requested at 2.40 or 2.41.
It appears it got something to do with keyframing i've read on the Adobe® Flex™ 3.5 Language Reference. The movie is a FLV file and i use the VideoDisplay object to display the movie.
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Nov 10, 2011
I just want to do not allow editing at some area of text area in flex. How it can be done?let suppose text length in text area is 50 characters, i want to allow editing if cursor position is less than 15, and if cursor position in text area is greater than 15 it should not allow user to add more text in text area.If user press any key it should not add any character in text area.[code]
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Aug 5, 2010
I have a couple of images, representing tents, that look like this: The red and blue parts on each side of the tents are doorways, and several tents can be connected together via these doorways. For example, I want to connect the two blue doorways so that they match up like in this picture: If the first tent is stationary, around which point do I rotate the second tent and how do I calculate where to place it?
Currently, I have the upper left corner of each doorway as an x and a y value, together with the width and direction (in degrees) of the door. I'm treating the doorways as one dimensional, so they don't have heights. Would another representation suit this better? Perhaps a start point and an end point plus direction?
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Nov 3, 2010
I am treating a spark TextArea as text input(by setting heightInLines="1"). The TextArea is part of an mxml component and I want to resize the component when the text is changed.
I haven't been able to use textArea.measureaText(textArea.text) to get line metrics and use it. I get this error "Parameter antiAliasType must be non-null."
Is there any way to get the width of a TextArea which it is going to consume at runtime for a particular string or a particular TextFlow?
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May 26, 2010
I'm trying to calculate how WIDE to make my button, based on the text that it will contain, and when I try to google for how to calcuate something as simplistic as the WIDTH OF SOME TEXT, I go cross-eyed just trying to wade through apparently nonsensical esoteric counter-intuitive voodoo. how I would write a function like this:
public function HowWideWouldThisTextBeIfItWereInThisButton(Text:String,Container:Button):int {
...
}
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