I have to display the Earth's map in azimuthal equidistant projection, by giving the lattitude and longnitude as input in Matlab. I am using the eqdazim projection, but I am still getting the map with point (0,0) in the center. I want to be able to change the point that is the center if the circle map.
landareas = shaperead('landareas.shp','UseGeoCoords',true);
axesm ('eqdazim', 'Frame', 'on');
geoshow(landareas);
Also, I don't know how to change the radius of the image. I don't need the circle with the whole Earth but instead something about ~2000km radius around center point.
I need it in order to put its image on a dome. Below is a simple example with such a dome and random fragment of the Earth's surface. Keep in mind, that it's just an image that I cropped manually from large Mercator map.
I was hoping that I can use the Mapping Toolbox in order to get such a map automatically, by giving lattitude, longnitude and radius. I have all necessary data, which is:
Lattitude & Longnitude
The radius of the circle
I just don't know how can I get this part of Earth's map. I think I have to use the azimuthal equidistant projection. I just don't know how to do this in MATLAB/Mapping Toolbox.
Related
I'm trying to programatically "draw" a circle with multiple Marker with React leaflet.
I'm doing it with cosinus and sinus trying to calculate theirs coordinate from the center point ...
But the more I'm near the pole the more the circle is an ellipssis ... Is it a way to transform the calculus to take this into account ?
In this example I'm in Oulu (near the pole) If you just change the x var into '0' you'll notice that the markers are now in circle !
please see this CodePen
Because a Leaflet map is a projection of a sphere onto a flat map, distortions will happen near the poles. You want to project your spherical Lat/Lng into flat Points, calculate the marker placements in flat Points and then unproject the points back to spherical LatLng.
I'm using canny edge detection to detect the edges of a rope and eliminate the background, then using morphological filters I'm filling these edges then thinning them to be in pixel size. The plot indicates the xy coordinates of the rope. What I need to do is to get the intersection of the scattered data (blue *) with the red circle (get the coordinates of Points (1,2,3,4).
Then I need to get the whole points coordinates from the point of intersection (point1,2,3,4) to the center,grouped as A,B,C,D.
The center of the circle, the origin of the axes, and the radius are all known.
I've tried some Matlab functions to get the four intersections points like
InterX,intersections
and also I tried to manually find the intersections
idx=find(y1-y2<eps);
but no method gives me the 4 intersection points.
Thank you in Advance
You'll need a thick circle. I presume (from your previous question) that the rope points are at contiguous integer coordinates. Using a thick circle (donut) with a width of 1 ensures you'll find at least one point in each rope end. Connected component analysis will then tell you which of these points belong to the same rope end.
I'm trying to find a way to rotate an arbitrary polygon around its own geometric center. It was drawn in a blackboard built with creating js.
I've been trying many approaches, but any of them has worked.
How can I accomplish it?
Find the geometric centre as the average of all the points' coordinates. Make all the points relative to this centre (such that the centre is (0,0)), then rotate them by the desired angle using a rotation matrix. You can then draw using these points.
This is assuming you have the coordinates of all the points.
I want to plot 3D cube of size 2x2x5 (x,y,z) around an interest point to get the nearest points to it and inside the cube. The interest point may be at the center of cube.
How can I get the nearest points to the interest point?
There are several techniques for drawing cubes here. You will need to choose one that lets you specify size and origin. The sizes will be 2,2,5, and the origin will be the coordinates of the interest point.
Can anyone point me in the right direction when it comes to understanding MKMapPoint?
I understand that it has to do with laying suface of the globe on a 2D surface. But I don't understand how each "point" is measured?
Can anyone give me an example in code?
There is nothing much to it.. just a structure to display point on a 2D map... here is what the documentation says..
MKMapPoint A point on a two-dimensional map projection.
typedef struct {
double x;
double y; } MKMapPoint;
Fields x The location of the point along the x-axis of the
map. y The location of the point along the y-axis of
the map. Discussion If you project the curved surface of the globe
onto a flat surface, what you get is a two-dimensional version of a
map where longitude lines appear to be parallel. Such maps are often
used to show the entire surface of the globe all at once. An
MKMapPoint data structure represents a point on this two-dimensional
map.
The actual units of a map point are tied to the underlying units used
to draw the contents of an MKMapView, but you should never need to
worry about these units directly. You use map points primarily to
simplify computations that would be complex to do using coordinate
values on a curved surface. By converting to map points, you can
perform those calculations on a flat surface, which is generally much
simpler, and then convert back as needed. You can map between
coordinate values and map points using the MKMapPointForCoordinate and
MKCoordinateForMapPoint functions.
When saving map-related data to a file, you should always save
coordinate values (latitude and longitude) and not map points.
Availability Available in iOS 4.0 and later. Declared In MKGeometry.h
If you want to draw something over a map that has a certain real-world size, for example, a scale, then in your calculations you would multiply any given length in meters with the result of MKMapPointsPerMeterAtLatitude(...) to get the size in MKMapPoint units.
If your map displays only of small portion of the globe, MKMapPointsPerMeterAtLatitude(...) will deliver roughly the same constant value for all the latitudes involved in your map. In this case, you can simply use the latitude in the middle of your map as the argument of this function.
Also read in the documentation that a Mercator projection is used for the transformation. Here is an additional observation: northing (y) axis direction seems to be in reverse direction of standard mercator projections (positive direction is down instead of up).