I have a bunch of lat/long coordinates and I need to draw a square polygon around each one. Each square will be a set size (e.g. 50x50) with the coordinate in the centre. I see there is a MKCircle class but is there an MKSquare equivalent (I couldn't fine one but that doesn't mean there isn't) and if there isn't, any suggestions on how this could be achieved? I have done some searching and didn't produce any solid suggestions.
I would also like to make the square 3D as in if the map is tilted it would show a height kind of like buildings.
You can use MKPolygon for this. Simply provide four coordinates the correct distance from your center point and the four coordinates will form a square.
Related
I am using opencv to determine coordinates the lane between two red lines like this:
Lane-detection:
It is not rectangle so I can't use cv2.rectangle to cover on it.
Does everyone have some ideas?
So first some background. Im developing a really simple 2D game, in Delphi 10.3, FMX, which at the bottom of the screen draws a random terrain for each level of the game.
Anyway, the terrain is just some random numbers which are used in Tpathdata and then i use fillpath to draw this 2d "terrain".
I want to check when a "falling" object, a trect for example, intersects with this terrain.
My idea was to get all the points of the tpathdata, every Y position of every X position of the screen width. This way i could easily check when an object intersects with the terrain.
I just cannout figure the way how to do it, or if anyone has any other solution. Id really appreciate any help. Thanks
This is not really a Delphi problem but a math problem.
You should have a math representation of your terrain. The polygon representing the boundary of the terrain. Then you need to use the math to know if a point is inside the polygon. See Wikipedia.
You may also implement it purely graphically using a B/W bitmap of the same resolution of the screen. You set the entire bitmap as white and draw the terrain on the bottom in white. Then checking the color of a pixel in that bitmap you'll know if it is outside of the terrain (black) or inside the terrain (white).
Given a photo containing a circle, for example this photo of a fountain:
is it possible to define the 3D position and rotation of the fountain in relation to the camera?
I realise we have to define the scale, so lets say the fountain is 2m wide (the diameter of the circle consisting of the inner rim of the fountain is 2m).
So assuming the circle is a perfect circle, and defining the diameter to 2m, is it possible to determine how the circle and the camera relate spatially? I dont know any camera matrix or anything, the only information i have is the picture.
I specifically want to determine the 3D coordinates of a given pixel on the rim of the fountain.
What would be the math and/or OpenCV code to do this?
Circle with perspective is an ellipse. So you basicly you need an ellipse detector.
This algorithm should work:
Detect all ellipses in the given image.
Filter ellipses that you think they are not a circles in origin. (This is not possible using just 1 Camera so you have to depend on previous knowledge. Something like that you knows that you are taking a photo for a circle).
mmm I stopped typing here and bring a paper&pen and started figuring how to estimate the Homography and it is not that easy! you should deal with the circle a special case of an ellipse and then try to construct a linear system of equations. However, I made quick googling :
https://www.researchgate.net/publication/265212988_Homography_estimation_using_one_ellipse_correspondence_and_minimal_additional_information
http://www.macs.hw.ac.uk/bmvc2006/papers/306.pdf
Seems very interesting topic, I am going to spare sometimes on it later!
What is best strategy to recreate part of a street in iOS SceneKit using .osm XML data?
Please assume part of a street is offered in the OSM XML data and contains the necessary geopoints with latitude and longitude denoting the Nodes to describe the paths/footprints of 6 buildings (i.e. ground floor plans that line the side of a street).
Specifically, what's the best strategy to convert latitude and longitude Nodes in order to locate these building footprints/polygons on the ground floor in a scene within SceneKit iOS? (i.e. running through position 0,0,0)? Thank you.
Very roughly and briefly, based on my own experience with 3D map rendering:
Transform the XML data from lat/long to appropriate coordinates for a 2D map (that is, project it to a plane using a map projection, then apply a 2D affine transform to get it into screen pixel coordinates). Create a 2D map that's wider and taller than the actual screen, because of what's going to happen in step 2:
Using a 3D coordinate system with your map vertical (i.e., set all the Z coordinates to zero), rotate the map so that it reclines at an appropriate shallow angle, as if you're in an aeroplane looking down on it; the angle might be 30 degrees from horizontal. To rotate the map you'll need to create a 3D rotation matrix. The axis of rotation will be the X axis: that is, the horizontal line that is the bottom border of your 2D map. The rotation is exactly the same as what happens when you rotate your laptop screen away from you.
Supply the new 3D coordinates to your rendering system. I haven't used SceneKit but I had a quick look at the documentation and you can use any coordinate system you like, so you will be able to use one that is convenient for the process I have just described: something that uses units the size of a screen pixel at the viewing plane, with Y going upwards, X going right, and Z going away from the viewer.
One final caveat: if you want to add extrusions giving a rough approximation of the 3D building shapes (such data is available in OSM for some areas) note that my scheme requires the tops of buildings, and indeed anything above ground level, to have negative Z coordinates.
Pretty simple. First, convert Your CLLocationCoordinate2D to a MKMapPoint, which is exactly the same as a CGRect. Second, scale down the MKMapPoint by some arbitrary number so it fits in with how you want it on your scene graph, let's say by 200. Since scenekit's coordinate system is centered at (0,0), you'll need to make sure your location is correct. Then just create your scnvector3's with the x/y of he MKMapPoint, and you will be locked to coordinates.
I have some polygon region (HRGN), and I want receive array of corner points. How can I do it in simple way in Delphi
In general case, there is no way to retrieve initial polygon vertices from HRGN.
Internally windows region consists of some rectangles.
Exact representation is possible for rectilinear region, but any slanted edge gives a lot of small rectangles (and slightly different polygons could give equal regions)
If your problem is to obtain a set of rectangles, then use GetRegionData function.