Point is a fundamental geometry type.

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55
votes
10answers
90k views

Convert Pixels to Points

I have a need to convert Pixels to Points in C#. I've seen some complicated explanations about the topic, but can't seem to locate a simple formula. Let's assume a standard 96dpi, how do I calulate ...
29
votes
7answers
20k views

Determine which side of a line a point lies

I've got a line through points (x1,y1) and (x2, y2). I'd like to see if point (x3, y3) lies to the "left" or "right" of said line. How would I do so?
11
votes
3answers
7k views

See if lat / long falls within a polygon using mysql

I have the created the table below CREATE TABLE geom (g GEOMETRY); and have inserted many rows, example below: INSERT INTO geom (g) VALUES(PolygonFromText('POLYGON(( 9.190586853 45.464518970, ...
4
votes
3answers
2k views

Get polygons close to a lat,long in MySQL

does anyone know of a way to fetch all polgons in a MySQL db within a given distance from a point. The actual distance is not that important since it's calculated for each found polygon later, but it ...
8
votes
2answers
4k views

ELF binary entry point

why is the entry point in each ELF binary something starting with 0x80xxxxx? Why doesn't the program start at (virtual) address 0x0? When executed, program will start running from virtual address ...
4
votes
1answer
4k views

Quadratic Bezier Curve: Calculate Point

Hey, I'd like to calculate a point on a quadratic curve. To use it with the canvas element of html5. When I use the quadraticCurveTo() Function in JavaScript, I have a source point, a target point ...
6
votes
2answers
2k views

Find the distance between two points in MYSQL. (using the Point Datatype)

Suppose I have a 2 column table like this: | user_id | int(11) | NO | UNI | NULL | | | utm | point | NO | MUL | NULL | | As you can see, it's ...
4
votes
2answers
1k views

Check if a point is in polygon (maps)

I'm trying to check if a point is in polygon. At the moment I have try with this function pointInPolygon:function (point,polygon){ var i; var j=polygon.length-1; var inPoly=false; ...
3
votes
4answers
4k views

How do I know if a Lat,Lng point is contained within a circle?

Ok pretty self explanatory. I'm using google maps and I'm trying to find out if a lat,long point is within a circle of radius say x (x is chosen by the user). Bounding box will not work for this. I ...
1
vote
3answers
2k views

opencv finding image cordinates on another image

How to find image "A" coordinates on image "B" which contains image "A". I wrote this program which is only checking pixel values, does anyone know is there any library tool do this.
0
votes
2answers
5k views

get the position of picturebox that has been clicked

I want to get the position of the picturebox that has been cliked by the mouse,but i don't know how?? I mean the position of picturebox not the form that the picturebox on it. thanks.
5
votes
1answer
1k views

Points moving along a curve within MATLAB

I have managed to edit a piece of code that was given to me in order to show a point moving along a curve. I am trying to find a way to edit this in order to create two independent points moving ...
4
votes
1answer
322 views

Why is Lua arithmetic is not equal to itself? [duplicate]

Possible Duplicate: What is a simple example of floating point/rounding error? When I execute the following Lua code: a = 5.6 b = 14 * 0.4 c = 11.2 / 2 d = 28 * 0.2 print( a == b ) print( ...
3
votes
2answers
665 views

How to make the + operator work while adding two Points to each other?

Is there any way to get the + operator to work for the Point object? Take, for example, this tiny snippet: this.cm1.Show((MouseEventArgs)e.Location+this.i_rendered.Location); You see, I try to ...
2
votes
2answers
195 views

How to use a timer inside a vertex shader to animate point sizes in OpenGL

I'm trying to implement a point cloud where the different points shall vary in size based on an uncertainty value associated with them. Let's say, if this value is zero, the size should be constant, ...

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