I'm using OsmDroid on OpenStreetMaps and can make markers and polylines, but I can't find any examples on how I'd make 161m/528ft circles around a marker.
a) How do I make circles?
b) How do I make them 161m/528ft in size?
Thanks to MKer, I got an idea on how to solve the problem and made this piece of code, which works:
oPolygon = new org.osmdroid.bonuspack.overlays.Polygon(this);
final double radius = 161;
ArrayList<GeoPoint> circlePoints = new ArrayList<GeoPoint>();
for (float f = 0; f < 360; f += 1){
circlePoints.add(new GeoPoint(latitude , longitude ).destinationPoint(radius, f));
}
oPolygon.setPoints(circlePoints);
oMap.getOverlays().add(oPolygon);`
I know this can be optimized. I'm drawing 360 points, no matter what the zoom is!
If you want a "graphical" circle, then you can implement easily your own CircleOverlay, using the DirectedLocationOverlay as a very good starting point.
If you want a "geographical" circle (than will appear more or less as an ellipse), then you can use the OSMBonusPack Polygon, that you will define with this array of GeoPoints:
ArrayList<GeoPoint> circlePoints = new ArrayList<GeoPoint>();
iSteps = (radius * 40000)^2;
fStepSize = M_2_PI/iSteps;
for (double f = 0; f < M_2_PI; f += fStepSize){
circlePoints.add(new GeoPoint(centerLat + radius*sin(f), centerLon + radius*cos(f)));
}
(warning: I translated from a Nominatim piece of code in PHP, without testing)
Related
the drawing algorithm which I currently use:
a_max = Pi*2 (float)(num_segments - 1.0f)/(float)num_segments;
for (unsigned int i = 0; i<=num_segments;i++)
{
const float a = (float)i / (float)num_segments * a_max;
SetPixel(centre.x + cos(a) *radius, centre.y +sin(a) *radius);
}
Works fine, but it starts drawing at (centre.x+radius, centre.y). I would like to have it to start at the top , because I want to draw a compass and zero degree is at the top, not on the right, so that I don't have to make a hacky solution.
Try rotating 90 degrees to the left before you start drawing, this should solve it for you.
A compass not only starts at "north" instead of "east" but also goes clockwise instead of counter-clockwise.
For this case, just swap sin(a) and cos(a):
x = centre.x + sin(a) * radius
y = centre.y + cos(a) * radius
I am having trouble configuring ICP in PCL 1.6(I use Android) and I believe that is the cause of an incorrect transformation matrix. What I've tried so far is this;
Downsample the point clouds I use in ICP with the following code:
pcl::VoxelGrid <pcl::PointXYZ> grid;
grid.setLeafSize(6, 6, 6);
grid.setInputCloud(output);
grid.filter(*tgt);
grid.setInputCloud(cloud_src);
grid.filter(*src);
Try to align the two point clouds with the following code :
pcl::IterativeClosestPoint<pcl::PointXYZ, pcl::PointXYZ> icp;
icp.setInputCloud(tgt);
icp.setInputTarget(src);
pcl::PointCloud<pcl::PointXYZ> Final;
pcl::PointCloud<pcl::PointXYZ> transformedCloud;
icp.setMaxCorrespondenceDistance(0.08);
icp.setMaximumIterations(500);
//icp.setTransformationEpsilon (0.000000000000000000001);
icp.setTransformationEpsilon(1e-12);
icp.setEuclideanFitnessEpsilon(1e-12);
icp.setRANSACIterations(2000);
icp.setRANSACOutlierRejectionThreshold(0.6);
I have tried all kinds of values in the options of ICP but with no success.
The code I use to create the point cloud:
int density = 1;
for (int y = 0; y < depthFrame.getHeight(); y = y + density) {
for (int x = 0; x < depthFrame.getWidth(); x = x + density) {
short z = pDepthRow[y * depthVideoMode.getResolutionX() + x];
if (z > 0 && z < depthStream.getMaxPixelValue()) {
cloud_src->points[counter].x = x;
cloud_src->points[counter].y = y;
cloud_src->points[counter].z = z;
}
}
}
Any chance somebody can help me out configuring ICP?
From what I know, PCL uses meters as a unit of measurement. so, is it intended that leaf size for downsampling is 6*6*6 !? I think it's huge !!
Try with some lower values and if it didn't work either, try ICP with the most simple configuration as follows :
pcl::IterativeClosestPoint<pcl::PointXYZ, pcl::PointXYZ> icp;
icp.setInputCloud(tgt);
icp.setInputTarget(src);
pcl::PointCloud<pcl::PointXYZ> Final;
icp.align(Final);
once, you got this working (and it should be), then start tuning the other parameters and it shouldn't be that hard to do.
Hope that helps, Cheers!
I'm having troubles finding a way to calculate a "cross-field" inside an arbitrary polygon.
A Cross field, as defined by one paper is the smoothest field that is tangential to the domain boundary (in this case the polygon) I find it a lot in quad re-topology papers but surprisingly not even in Wikipedia I can find the definition of a Cross field.
I have images but since I'm new here the system said I need at least 10 reputation points to upload images.
Any ideas?
I think it could be something along the lines of an interpolation? given an inner point determine the distance to each edge and integrate or weight sum the tangent and perpendicular vector of every edge by the distance? (or any other factor in fact)
But other simpler approaches may exist?
Thanks in advance!
//I've come up with something like this (for the 3D case), very raw, educational purposes
float ditance2segment(Vector3D p, Vector3D p0, Vector3D p1){
Vector3D v = p1 - p0;
Vector3D w = p - p0;
float c1 = v.Dot(w);
if (c1 <= 0)
return (p - p1).Length();
float c2 = v.Dot(v);
if (c2 <= c1)
return (p - p1).Length();
float b = c1 / c2;
Vector3D pb = p0 + b*v;
return (p - pb).Length();
}
void CrossFieldInterpolation(List<Vector3D>& Contour, List<Vector3D>& ContourN, Vector3D p, Vector3D& crossU, Vector3D& crossV){
int N = Contour.Amount();
for (int i=0; i < N; i++){
Vector3D u = Contour[(i + 1) % N] - Contour[i];
Vector3D n = 0.5*(ContourN[(i + 1) % N] + ContourN[i]);
Vector3D v = -Vector3D::Cross(u,n); //perpendicular vector
u = Vector3D::Normalize(u);
n = Vector3D::Normalize(n);
v = Vector3D::Normalize(v);
float dist = ditance2segment(p, Contour[i], Contour[(i+1)%N]);
crossU += u / (1+dist); //to avoid infinity at points over the segment
crossV += v / (1+dist);
}
crossU = Vector3D::Normalize(crossU);
crossV = Vector3D::Normalize(crossV);
}
You can check the OpenSource Graphite software that I'm developping, it implements the "Periodic Global Parameterization" algorithm [1] that was developed in my research team. You may be also interested in the following research articles with algorithms that we developed more recently [2],[3]
Graphite website:
http://alice.loria.fr/software/graphite
How to use Periodic Global Parameterization:
http://alice.loria.fr/WIKI/index.php/Graphite/PGP
[1] http://alice.loria.fr/index.php/publications.html?Paper=TOG_pgp%402006
[2] http://alice.loria.fr/index.php/publications.html?Paper=DGF#2008
[3] http://alice.loria.fr/index.php/publications.html?redirect=0&Paper=DFD#2008&Author=vallet
I tweaked https://github.com/daCapricorn/ArcMenu library to make it work from my purpose and that is working fine. Is there anyway I can build a menu like as in tumblr app or is it possible by tweaking the ArcMenu project or https://github.com/siyamed/android-satellite-menu ? I have doubts on the mathematical functions to be applied to create the style.
I am looking for a animation similar to tumblr app's animation.
try to use , Arc Menu
implement RayMenu and modify RayLayout
and modify the private static AnimationcreateExpandAnimation()` method with your specific coordinate.
There are many ways I do this in iOS. In iOS we have Views similar to that of Android and we can specify coordinates (frame of view) to place them in their superview.
Assumptions :
1)Assume you have a locus i.e circle with equation x^2 + y^2 = c
( Hint : All views are on this locus i.e center of all views coincide with this circle)
2) You need select a value of C depending on the curve you need and initial point which is
(0,HEIGHT_OF_SCREEN) as stating point for placing views.
Algorithm :
int angularDisplacementBetweenEachView = 10; // distance between two views in radians
// coordinates of X button in your screen
int startPositionOfViewX = 0;
int startPositionOfViewY = HEIGHT_OF_SCREEN;
// constant to decide curve
int C = 125;
-(void) main (){ // this is generally done in view controller
for(int i = 1; i< menu_items.count; i++){
Rect position = getCoordinatesForView(menu_item.get(i),menu_item.get(i-1).rect.x,menu_item.get(i-1).rect.y);
addView(menu_item.get(i),position.x,position.y);
}
}
// method returns the coordinates (x,y) at which the view is required to be
//placed.
-(Rect)getCoordinatesForView(View currentView, int prevViewX, int prevViewY){
// convert to polar cordinates
// refer diagram
// this is also the radius of the virtual circle
float r = sqrt(pow(x,2),pow(y,2));
float theta = atan(y,x);
//r & theta are polar coordinates of previous menu item
float theta2 = (angularDisplacementBetweenEachView + r*theta)/r;
// convert back to cartesian coordinates
int x2 = r * cos (theta);
int y2 = r * sin (theta);
return new rect(x2,y2);
}
try this for Arc menu. u can use this sattelite menu
https://github.com/ketanpatel25/android-satellite-menu-center
I'm responsible for delivering pages to display primary results for the US elections State by State. Each page needs a banner with an image of the State, approx 250px by 250px. Now all I need to do is figure out how to serve / generate those images...
I've dug into the docs / examples for Protovis and think I
could probably lift the State coordinate outlines- I would have to
manually transform the coordinate data to be justified and sized
properly (ick)
At the other end of the clever/brute spectrum is an enormous sprite
or series of sprites. Even with png 8 compression the file size of
a grid of 50 non-overlapping 250x250px sprites is a concern, and
sadly such a file doesn't seem to exist so I'd have to create it
from hand. Also unpleasant.
Who's got a better idea?
Answered: the right solution is to switch to d3.
What we hacked in for now:
drawStateInBox = function(box, state, color) {
var w = $("#" + box).width(),
h = $("#" + box).height(),
off_x = 0,
off_y = 0;
borders = us_lowres[state].borders;
//Preserve aspect ratio
delta_lat = pv.max(borders[0], function(b) b.lat) - pv.min(borders[0], function(b) b.lat);
delta_lng = pv.max(borders[0], function(b) b.lng) - pv.min(borders[0], function(b) b.lng);
if (delta_lat / h > delta_lng / w) {
scaled_h = h;
scaled_w = w * delta_lat / delta_lng;
off_x = (w - scaled_w) / 2;
} else {
scaled_h = h * delta_lat / delta_lng;
scaled_w = w;
off_y = (h - scaled_h) / 2;
}
var scale = pv.Geo.scale()
.domain(us_lowres[state].borders[0])
.range({x: off_x, y: off_y},
{x: scaled_w + off_x, y: scaled_h + off_y});
var vis = new pv.Panel(state)
.canvas(box)
.width(w)
.height(h)
.data(borders)
.add(pv.Line)
.data(function(l) l)
.left(scale.x)
.top(scale.y)
.fillStyle(function(d, l, c) {
return(color);
})
.lineWidth(0)
.strokeStyle(color)
.antialias(false);
vis.render();
};
d3 seems to have the capability to do maps similar to what you want. The example shows both counties and states so you would just omit the counties and then provide the election results in the right format.
There is a set of maps on 50states.com, e.g. http://www.50states.com/maps/alabama.htm, which is about 5KB. Roughly, then, that's 250KB for the whole set. Since you mention using these separately, there's your answer.
Or are you doing more with this than just showing the outline?