I have calculated the bearing of two sets of points using the ST_Azimuth (geometry) function of Postgis.
I get values like
1.42985896479537
1.44293722688266
1.45994672393791
1.48436591051383
1.51617271196433
4.22987568535437
4.27561945155804
can anyone tell me how to make sense of them.
I am trying to locate points which are on right and which are on left side of other point set.
Use like this:
select
degrees(st_azimuth(geom,geom)) as your_column
from
your_table;
Related
I'm trying to move an object called "car" via the dat.gui. If the user changes the x value using the dat.gui slider, the car should move along the x-axis of its local coordinate system.
here I have copied the part of the code that is causing me problems:
var m = new THREE.Vector3;
m.copy(car.position);
if (changed.key=='X') car.translateX(changed.value-car.worldToLocal(m).x);
My problem is that the expression in car.translateX always evaluates to the value that is in changed.value. The part after the minus has no effect at all or maybe is permanently 0. I have printed the values with console.log and the values of car.position.x and m change in each step, but the subtraction still delivers in every step only the result that is already in changed.value anyway. Can someone help me and tell me why this happens?
Unfortunately, I am absolutely stuck.
car.worldToLocal(m)
I'm afraid this piece of code makes no sense since car.position (and thus m) already represents the car's position in local space.
Instead of using translateX() you achieve the same result by modifying car.position directly:
car.position.x = changed.value;
I'm not seeing an IndexOf or FindIndex method for SKPath.Points. I need to be able to get neighbouring points on both sides of a specified point. Path.Iterator only has .Next, so I am looking for using the index of the SKPoint instead.
With IndexOf or FindIndex seemingly missing, I am thinking of inheriting and maintaining a 2nd dataset in the background for getting the index.
Am I missing something obvious? How are others getting the index, so far?
This post helped. Calling IndexOf directly on Array works. Just need to make sure your SKPoint X and Y are unique from other SKPoints stored in the SKPath.Points. It is doing the check based on the SKPoint's position, so if you have multiple SKPoints at (0, 0), for example, it will return the first one at that position.
Luckily, I should never be in the situation for my use case.
I am migrating a THREE.js app from r60 to r70. Amongst other changes I notice that r60 constructs of the following form no longer work in r70.
mesh.position.set(0,0,0);
myVector3 = new THREE.Vector3 (100,200,300);
mesh.position = myVector3;
This applies to meshes, pointLights, presumably to all Object3D's but I havent tested further.
In the above example the mesh.position x,y,z values remain unchanged at (0,0,0). For illustration see this JSFiddle and compare lines 70 and 73.
//...The next line DOES NOT update Sphere_mesh.position.x
Sphere_mesh.position = NewPos_vector3;//...
//...The next line DOES update Sphere_mesh.position.x
Sphere_mesh.position.x = NewPos_vector3.x
In a debugger no console warning is given during execution that the assignment has not worked. In the very brief THREE.js migration notes for (r68 --> r69) I see something about an Object3D's position no longer being immutable but I don't know what that means.
Anyway, my question
Is there a standard THREE construct or function I can use to copy x,y,z values from a Vector3 object to the x,y,z values of a mesh.position rather than the effective, but verbose, form such as
mesh.position.x = myVector3.x;
mesh.position.y = myVector3.y;
mesh.position.z = myVector3.z; ?
e.g. something such as
mesh.position = F_Get_Object3DPosition_from_Vector3(myVector3); ?
I know it would be easy to write my own function but a standard THREE function would be more likely to evolve smoothly with future versions of THREE.
position beeing immutable means that the position property can not be changed.
so
mesh.position = anything;
won't work (but you already discovered this)
what you can do is not change the position, but you have to change position values.
in your case, the easiest way is
mesh.position.copy (myVector3);
I think you meant myVector3 not myVector3() in the last line... Anyway, I though that would work too but the thing is, you are applying a Vector to something that supposed to be a point/Vertex. Even if that worked in my opinion it wasn't the right way to do it. How about using a simple array:
mesh.position.set(0,0,0);
new_position = [100,200,300]
mesh.position.fromArray(new_position,0)
in which 0 is the starting index. So you can have multiple position sets in one array
I'm currently tying to geocode addresses in Austria. From a given postal code and street etc. I want to automatically find latitude and longitude in WGS84 format. My first approach was to use a webservice like OpenStreetMaps Nominatim. Actually this gives decent results.
Still it is mandatory to use a disk with addresses (PAC) and their respective geolocation as a ground truth. Only if I'm not able to match the address within this data I can use the web service approach as a backup solution.
So much for context, now the problem:
On this disk the gelocation is given as X_LAMBERT and Y_LAMBERT and I can't quite figure out how to convert into latitude+longitude.
The diks's data is loaded into an Oracle 11g database with Locator and I'm doing the following:
Step 1:
Creation of spatial geometry object: MDSYS.SDO_GEOMETRY(2003,31287,NULL, MDSYS.SDO_ELEM_INFO_ARRAY(1,1003,1), MDSYS.SDO_ORDINATE_ARRAY(X_LAMBERT,Y_LAMBERT))
Step 2: Projection from WGS84 to LatLng:
SDO_CS.TRANSFORM( GEOMETRY, 4326) in my Java client I obtain latitude, longitude from the geometry via oracle.spatial.geometry.JGeometry.
Note:
I suspect 31287 to be SRID of the lambert format, I tried 8307 and 3416, but latter give even worse results.Step 2 works fine with other geometry objects, where I know the correct SRID for sure... so I guess the error is somewhere in Step 1.
Do I have to set something in USER_SDO_GEOM_METADATA ? Wrong usage of SDO_GEOMETRY constructor ? Am I still mixing up datum and projection? Maybe you can enlighten me there aswell...
The result of my action and example for input are:
Input: X_LAMBERT 602823, Y_LAMBERT 464397
Resulting Output: WGS84 (48.0469757028535, 16.0542604612583)
Expected Output: WGS84 (48.546363, 16.085735)
Its like almost correct, but still some 100 kilometers off ;-)
I have been looking everywhere but I can't find a site that shows how to do this.
The thing I want is to be able to select an object from an axes when I click it, so that I can change its colours and stuff.
I just can't figure out how to select a child, I can create objects but not select them.
I have this piece of code I use to create a line:
coord = ginput (2)
x = coord(:,1)
y = coord(:,2)
hline = line(x,y)
I'm not sure If i need to create the objects in an array so that I can select edit/delete them.
I believe I would need to use ButtonDownFcn, but probably I'm doing something completely wrong.
Any help would be appreciated, If I'm missing any information please let me know
Thanks
It is not necessary to use ginput and extract the coordinates. This is done automatically by an built-in "listener" in the figure-window. You are correct in assuming that you can use the ButtonDownFcn property on the object (line, lineseries, or other handle graphics object).
Try to create at simple line from (0,0) to (1,1):
hline = line([0,1],[0,1]) %# create line, save handle in hline
Then you can set the ButtonDownFcn to, for instance, a function handle to an anonymous function:
set( ...
hline, ...
'ButtonDownFcn', #(handle,event)(disp(['You clicked on the line!'])) ...
);
Now try to click on the line. It should print the text in the command window.
The function needs to be able to receive atleast two arguments: (1) the handle of the object itself (the line) and (2) an "event structure". I believe the second argument is just empty when you use line-objects. But your function still needs to receive atleast these two arguments (even if you do not use them).
Read more here: http://www.mathworks.com/help/techdoc/ref/line_props.html.
You can also use your own function (a named function in a file):
set( ...
hline, ...
'ButtonDownFcn', #(handle,event)(namedFunction(handle,event)) ...
);
... or you can use a struct-array if you (expectedly) have other arguments beyound those two.