Tinkerpop Frames: Get Edge when adding a vertex - orientdb

i followed the example on https://github.com/tinkerpop/frames/wiki/Getting-Started and wanted to do the following: When adding a new Project, for example
marko.addCreatedProject(pr);
i also want to get the edge between marko and pr to set the weight, for example. One way to do this is to get all outgoing vertices of marko and find pr in the list of vertices. Is there a better way to do this? Is it possible to return the edge, when i call addCreatedProject, to do the following:
CreatededInfo cr = marko.addCreatedProject(pr);
cr.setWeight(3);

You could try using the addEdge method on FramedGraph which returns the Edge when you supply two vertices to relate. So a little more fine grained.
E.g.
com.tinkerpop.frames.FramedGraphFactory.FramedTransactionalGraph graph = ...
Vertex user1 = graph.addVertex(null);
Vertex project1 = graph.addVertex(null);
Edge newEdge = graph.addEdge(null, user1, project1, "CREATED");
// ... do something with newEdge
The tinkerpop FramedGraph interface also has overloaded methods for addVertex and addEdge, so that you can supply your framed Class type, to have a Framed vertex or edge returned which can be convenient.
E.g.
Vertex user1 = graph.addVertex(null, Person.class);
Vertex project1 = graph.addVertex(null, Project.class);
Edge newEdge = graph.addEdge(null, user1, project1, "CREATED",Direction.OUT, MyEdge.class);
And of course you can graph.frame(newEdge, MyEdge.class) after the fact too, if you only have a com.tinkerpop.blueprints.Edge.
Here is the Javadoc for FramedGraph

Related

Orientdb - Traverse based on a specific edge field

In the figure below each vertex is connected to others with edges of class E_FIELD. Each edge has a field called propName. Starting from a vertex I need to traverse through edges with propName set a specific value. In the figure below, I need to start from vertex 1 and traverse through the edges which have 'place' as their propName fields (going from 1 to 2 and then to 3). It should exclude vertex 4 as its propName is not set to place. How can I do this?
The following query should help you in your quest:
SELECT FROM (TRAVERSE * FROM <your_vertex_rid>) WHERE #class = "E_FIELD" AND propName = "place"

Compare value of property of all instances of class in python

I'm trying to write an object oriented program (as a learning exercise, I know there may be simpler ways to do it) in which beads bounce around a 2D plane bounded by a ring. Each bead is an object defined by a class ball. In setting the initial positions of the balls I need to check that no other ball has already been placed at the same x and y coordinates.
#Class for the beads
class ball:
NumbBalls = 0
#Constructor
def __init__(self,Beads):
self.ball = sphere(pos = vector(0,0,0), radius = radiusBall,color=color.red)
ball.NumbBalls += 1
self.ball.pos = self.createInitialPosition(Beads)
#Assign ball its initial position
def createInitialPosition(self,other):
#CODE to compare self.ball.pos and other.ball.pos which returns a unique position coordinate
#Main program
NumbBeads = 100
Beads = []#Create empty list for all the beads
#create balls in random initial positions
Beads = [ball(Beads) for item in range(NumbBeads)]
I can get this to work if I create two objects bead1 and bead2 and then pass bead1 and bead2 as arguments ie bead2 = ball(bead1) but how do I do this if I am generating a list of beads and want all of them to be compared with self. Hopefully that makes sense.
Perhaps rather than the approach you are currently taking, you should consider something along these lines (of course, with the necessary changes to your class definition/methods):
N = 100
initialPositions = []
while len(initialPositions) <= N:
newPosition = generateRandomPosition()
if newPosition in initialPositions:
pass
else:
initialPositions.append(newPosition)
ballList = [ ball(p) for p in initialPositions ]
In other words, generate a list of initial positions outside of the creation of your objects, and do whatever validation/restriction you need during that creation. Then just create your objects from that list. If N is really large, you might want to consider a dictionary (or a mutable set of some sort) instead of a list for initialPositions, to help speed up the membership testing, but it's still the same concept...

World.QueryAABB giving incorrect results in libgdx

I'm trying to implement mouse selection for my game. When I QueryAABB it looks like it's treating objects much larger than they really are.
Here's what's going on in the image
The blue box is an actor containing a body that I'd like to select
The outline on the blue box is drawn by Box2DDebugRenderer
The mouse selects a region on the screen (white box), this is entirely graphical
The AABB is converted to meters and passed to QueryAABB
The callback was called for the blue box and turned it red
The green outline left behind is a separate body to check if my conversions were correct, this is not used for the actual selection process
It seems to be connected to my meter size, the larger it is, the more inaccurate the result is. At 1 meter = 1 pixel it works perfectly.
Meter conversions
val MetersToPixels = 160f
val PixelsToMeters = 1/MetersToPixels
def toMeters(n: Float) = n * PixelsToMeters
def toPixels(n: Float) = n * MetersToPixels
In the image I'm using MetersToPixels = 160f so the inaccuracy is more visible, but I really want MetersToPixels = 16f.
Relevant selection code
val x1 = selectPos.x
val y1 = selectPos.y
val x2 = getX
val y2 = getY + getHeight
val (l,r) =
if (x2 < x1)
(x2,x1)
else
(x1,x2)
val (b,t) =
if (y2 < y1)
(y2,y1)
else
(y1,y2)
world.QueryAABB(selectCallback, toMeters(l),toMeters(b), toMeters(r),toMeters(t))
This code is inside the act method of my CursorActor class. And selectPos represents the initial point where the use pressed down the left mouse button and getX and getY are Actor methods giving the current position. The next bit sorts them because they might be out of order. Then they are converted to meters because they are all in pixel units.
selectCallback: QueryCallback
override def reportFixture(fixture: Fixture): Boolean = {
fixture.getBody.getUserData match {
case selectable: Selectable =>
selected += selectable
true
case _ => true
}
}
Selectable is a trait that sets a boolean flag internally after the query which helps determines the color of the blue box. And selected is a mutable.HashSet[Selectable] defined inside of CursorActor.
Other things possibly worth noting
I'm new to libgdx and box2d.
The camera is scaled x2
My Box2DDebugRenderer uses the camera's combined matrix multiplied by MetersToPixels
From what I was able to gather, QueryAABB is naturally inaccurate for optimization. However, I've hit a roadblock with libgdx because it doesn't have any publicly visible function like b2testOverlap and from what I understand, there's no plan for there to be one any time soon.
I think my best solution would probably be to use jbox2d and pretend that libgdx's physics implementation doesn't exist.
Or as noone suggested I could add it to libgdx myself.
UPDATE
I decided to go with a simple solution of gathering the vertices from the fixture's shape and using com.badlogic.gdx.math.Intersector against the vertices of the selection. It works I guess. I may stop using QueryAABB all together if I decide to switch to using a sensor for the select box.

Intersecting Layers Returns Empty Collection Despite Visible Intersection

When I perform an intersection of a polygon I draw in OpenLayers and a postgis database layer, it seems that I am getting incorrect results.
Intersection works correctly on some layers. For instance, if I intersect a triangle with a layer of polygons that represent crop fields, I get the following:
The query my app generates to produce the above result is:
SELECT ST_AsText(ST_Intersection(%(geometries_0)s::geometry, %(geometry)s::geometry))
where geometries_0 is my triangle:
POLYGON((-104.84928345939991 40.518951354186285,-104.82319093011056 40.51953858115158,-104.83700967095314 40.50707521626648,-104.84928345939991 40.518951354186285))
and geometry is my layer of crop fields, as well-known text:
MULTIPOLYGON(((-104.841309611298 40.5075331998226,-104.84173356681 40.5069932245841,-104.842041204329 40.50640946683,-104.842224948796 40.5057962996657,-104.842280275816 40.5051688207073,-104.842205823049 40.5045424803865,-104.842003423773 40.5039327015263,-104.841678061729 40.5033544995574,-104.841237748411 40.502822112724,-104.840693325791 40.5023486513933,-104.840058199365 40.5019457751149,-104.839348008051 40.5016234053897,-104.838580239118 40.5013894812384,-104.837773797582 40.5012497635973,-104.836948540713 40.501207693373,-104.836124789073 40.5012643066572,-104.83532282616 40.5014182091969,-104.834562398965 40.5016656107496,-104.833862231727 40.5020004184754,-104.833239564888 40.5024143870601,-104.832709730574 40.5028973218633,-104.83228577506 40.5034373300773,-104.831978137541 40.5040211136997,-104.831794393074 40.5046342970926,-104.831739066055 40.5052617810515,-104.831813518821 40.5058881146554,-104.832015918097 40.5064978757385,-104.832341280141 40.5070760506105,-104.83278159346 40.5076084036796,-104.833326016079 40.5080818278834,-104.833961142505 40.5084846673069,-104.834671333819 40.5088070040565,-104.835439102753 40.5090409023397,-104.836245544289 40.5091806037522,-104.837070801158 40.5092226689759,-104.837894552799 40.5091660624086,-104.83869651571 40.509012177646,-104.839456942906 40.5087648031902,-104.840157110143 40.5084300292289,-104.840779776982 40.5080160977709,-104.841309611298 40.5075331998226)))
However, if I perform the same query with a different layer ("soils"), I get an empty result:
The query is the same:
SELECT ST_AsText(ST_Intersection(%(geometries_0)s::geometry, %(geometry)s::geometry))
with a polygon geometries_0 that should overlap:
POLYGON((-104.84627938530097 40.54511058649626,-104.83460641167578 40.545175808723876,-104.84070039055733 40.537283458057615,-104.84627938530097 40.54511058649626))
and a geometry layer representing soils, similar to the crop fields in the above query:
MULTIPOLYGON(((-104.939716 40.258166,-104.939775 40.258174,-104.939963 40.258159,-104.940159 40.258065,-104.940039 40.257671,-104.939917 40.25749,-104.939928 40.257419,-104.94003 40.257404,-104.940265 40.257641,-104.940632 40.257902,-104.940826 40.258061,-104.941051 40.258188,-104.941123 40.258235,-104.941205 40.258283,-104.941246 40.258275,-104.941287 40.258212,-104.941186 40.258094,-104.941186 40.258007,-104.941167 40.257921,-104.941105 40.257858,-104.941044 40.257786,-104.941045 40.257716,-104.941127 40.257676,-104.94122 40.257653,-104.94141 40.257731,-104.941559 40.257671,-104.941255 40.257181,-104.940857 40.256794,-104.940644 40.256478,-104.940319 40.255997,-104.940003 40.255728,-104.939676 40.255561,-104.939419 40.255544,-104.938895 40.255529,-104.938287 40.255512,-104.938046 40.255528,-104.937733 40.255549,-104.937322 40.255533,-104.937012 40.255577,-104.936947 40.255593,-104.936623 40.255774,-104.936581 40.255924,-104.93658 40.256042,-104.936661 40.256223,-104.93671 40.256436,-104.936842 40.256618,-104.937262 40.256753,-104.937662 40.256818,-104.937897 40.257,-104.938181 40.25745,-104.938374 40.257742,-104.938465 40.257931,-104.938782 40.258051,-104.939121 40.258092,-104.939439 40.258133,-104.939716 40.258166)))
I use the postgis ST_AsText function to convert database layers to well-known text, and I checked to make sure that all layers have the EPSG:4326 projection (using the Find_SRID function).
Why would one layer (crop fields) intersect correctly, and another (soils) not? I've tried the same query using geographies instead of geometries, with the same result.
It returns an empty collection because they don't intersect. In fact, they are 32 km away from each other.
SELECT ST_Intersects(A, B), ST_Distance(A, B)/1000 AS dist_km
FROM (
SELECT
'POLYGON((-104.84627938530097 40.54511058649626,-104.83460641167578 40.545175808723876,-104.84070039055733 40.537283458057615,-104.84627938530097 40.54511058649626))'::geography AS A,
'MULTIPOLYGON(((-104.939716 40.258166,-104.939775 40.258174,-104.939963 40.258159,-104.940159 40.258065,-104.940039 40.257671,-104.939917 40.25749,-104.939928 40.257419,-104.94003 40.257404,-104.940265 40.257641,-104.940632 40.257902,-104.940826 40.258061,-104.941051 40.258188,-104.941123 40.258235,-104.941205 40.258283,-104.941246 40.258275,-104.941287 40.258212,-104.941186 40.258094,-104.941186 40.258007,-104.941167 40.257921,-104.941105 40.257858,-104.941044 40.257786,-104.941045 40.257716,-104.941127 40.257676,-104.94122 40.257653,-104.94141 40.257731,-104.941559 40.257671,-104.941255 40.257181,-104.940857 40.256794,-104.940644 40.256478,-104.940319 40.255997,-104.940003 40.255728,-104.939676 40.255561,-104.939419 40.255544,-104.938895 40.255529,-104.938287 40.255512,-104.938046 40.255528,-104.937733 40.255549,-104.937322 40.255533,-104.937012 40.255577,-104.936947 40.255593,-104.936623 40.255774,-104.936581 40.255924,-104.93658 40.256042,-104.936661 40.256223,-104.93671 40.256436,-104.936842 40.256618,-104.937262 40.256753,-104.937662 40.256818,-104.937897 40.257,-104.938181 40.25745,-104.938374 40.257742,-104.938465 40.257931,-104.938782 40.258051,-104.939121 40.258092,-104.939439 40.258133,-104.939716 40.258166)))'::geography AS B
) AS data;
st_intersects | dist_km
---------------+------------------
f | 32.1052124928391
Something with your map is incorrect.
After some debugging (in addition to some helpful troubleshooting steps) I realized that I was building my WKT blobs incorrectly using the ST_AsText function, specifically for my soils layer. As a result, my intersection was not being applied to the entire set of geometries contained within my soils layer.
Currently my soils layer contains a subset of SSURGO soil map units, some of which do not actually contain a geometry. In order to correctly build a text string representing all non-null geometries, I needed to explicitly join the geometries before converting the result to WKT:
SELECT ST_AsText(ST_Union(the_geom)) FROM schema.layer
did the trick.

FromPoint does not intersect it's own IPolyline5

I have a Polyline and a Point FeatureClass.
I create a point feature on the Point layer for both the FromPoint and the ToPoint of the IPolyline5 similar to below:
IFeature pointFeature1 = pointFeatureClass.CreateFeature ();
pointFeature1.Shape = polyline.FromPoint;
IFeature pointFeature2 = pointFeatureClass.CreateFeature ();
pointFeature2.Shape = polyline.ToPoint;
Later, I then run both the from point and to point geometries through a method like the below to find all the intersecting polyline features from the polyline feature class.
ISpatialFilter filter = new SpatialFilter ();
filter.Geometry = pointGeometry;
filter.SpatialRel = esriSpatialRelEnum.esriSpatialRelIntersects;
IFeatureCursor cursor = lineFeatureClass.FeatureClass.Search (filter, false);
At the very least, the intersect filter should find the polyline off which I got the 2 points. The strange thing is, it works for the FromPoint, but not with the ToPoint.
Both feature classes are using the same Geographic Coordinate System and Projected Coordinate System.
I hope I am doing something stupid, but just can't figure out what.
I got it to work consistently with esriSpatialRelIntersects by just buffering the point by 0.001.
When creating new features from existing features, you should not use the direct reference, but the ShapeCopy. Try to change yout first block to:
pointFeature1.Shape = polyline.FromPoint.ShapeCopy;
pointFeature2.Shape = polyline.ToPoint.ShapeCopy;
instead of
pointFeature1.Shape = polyline.FromPoint;
use
PointFeature1.Shape = ((polyline.FromPoint as IPoint) as IFeature).ShapeCopy;
and for
pointFeature2.Shape = polyline.ToPoint;
use
PointFeature1.Shape = ((polyline.ToPoint as IPoint) as IFeature).ShapeCopy;