Geek Answers Handbook

GPS point compression

I have a device that records GPS data. Reading is done every 2-10 seconds. For an activity that takes 2 hours, there are many GPS points.

Does anyone know of a data set compression algorithm by removing redundant data points. those. if the row of data points is in a straight line, then only the start and end points are required.

+5
source share
5 answers

check out the Douglas Peucker Algorithm , which is used to simplify the polygon. I used this successfully to reduce the number of gps waypoints when they were handed over to clients for display purposes.

+6
source

, , x (t), y (t) . - : http://www.youtube.com/watch?v=YtcZXlKbDJY???

+1

, , .

, ++, :

struct Point
{
   double x;
   double y;
};

double calculate_slope(Point const& p1, Point const& p2)
{
    //      dy     y2 - y1
    // m = ---- = ---------
    //      dx     x2 - x1
    return ((p2.y - p1.y) / (p2.x - p1.x));
}

// 1. Read first two points from GPS stream source
Point p0 = ... ;
Point p1 = ... ;

// 2. Accept p0 as it first point

// 3. Calculate slope
double m0 = calculate_slope(p0, p1);

// 4. next point is now previous
p0 = p1;

// 5. Read another point
p1 = ... ;
double m1 = calculate_slope(p0, p1);

// 6. Eliminate Compare slopes
double const tolerance = 0.1; // choose your tolerance
double const diff = m0 - m1;
bool if (!((diff <= tolerance) && (diff >= -tolerance)))
{
    // 7. Accept p0 and eliminate p1

    m0 = m1;
}

// Repeat steps from 4 to 7 for the rest of points.

, .

+1

GPS .

, CodeProject GPS. , , , - , . , .

0

, :

  • " " , , NNE-NNW , NE SE ( , y -).

    , . ( , .) . .

  • , , ENE, ESE, , ENE ESE.

, , - , , . . . lib2geom bezier-utils.cpp. , (i) , ; (ii) , , , , ( - ).

0

More articles:


All Articles