My Codename One app features a MapContainer. I need to show points of interest (POIs) on it which coordinates reside on the server. There can be hundreds (maybe thousands in the future) of such POIs on the server. That's why I would like to only download from the server the POIs that can be shown on the map. Consequently I need to get the map boundaries to pass them to the server.
I read this for Android and this other SO question for iOS and the key seems to get the map Projection and the map bounding box. However the getProjection() method or the getBoundingBox() seem not to be exposed.
A solution could be to mix the coordinates from getCameraLocation() which is the map center and getZoom() to infer those boundaries. But it may vary depending on the device (see the shown area can be larger).
How can get the map boundaries in Codename one ?
Any help appreciated,
Cheers,
The problem is in the javadocs for getCoordAtPosition(). This will be corrected. getCoordAtPosition() expects absolute coordinates, not relative.
E.g
Coord NE = currentMap.getCoordAtPosition(currentMap.getWidth(), 0);
Coord SW = currentMap.getCoordAtPosition(0, currentMap.getHeight());
Should be
Coord NE = currentMap.getCoordAtPosition(currentMap.getAbsoluteX() + currentMap.getWidth(), currentMap.getAbsoluteY());
Coord SW = currentMap.getCoordAtPosition(currentMap.getAbsoluteX(), currentMap.getAbsoluteY() + currentMap.getHeight());
I tried this out on the coordinates that you provided and it returns valid results.
EDIT March 21, 2017 : It turns out that some of the platforms expected relative coordinates, and others expected absolute coordinates. I have had to standardize it, and I have chosen to use relative coordinates across all platforms to be consistent with the Javadocs. So your first attempt:
Coord NE = currentMap.getCoordAtPosition(currentMap.getWidth(), 0);
Coord SW = currentMap.getCoordAtPosition(0, currentMap.getHeight());
Will now work in the latest version of the library.
I have also added another method : getBoundingBox() that will get the bounding box for you without worrying about relative/absolute coordinates.
This is probably something that can be exposed easily by forking the project and providing a pull request. We're currently working on updating the map component so this is a good time to make changes and add features.
Related
I followed multiple example, to train a custom object detector in TensorflowJS . The main problem I am facing every where it is using pretrained model.
Pretrained models are fine for general use cases, but custom scenario it fails. For example, take this this is example form official Tensorflowjs examples, here it is using mobilenet, and mobilenet and mobilenet has image size restriction 224x224 which defeats all the purpose, because my images are big and also not of same ratio so resizing is not an option.
I have tried multiple example, all follows same path oneway or another.
What I want ?
Any example by which I can train a custom objector from scratch in Tensorflow.js.
Although the answer sounds simple but trust me I searching for this for multiple days. Any help will be greatly appreciated. Thanks
Currently it is not yet possible to use tensorflow object detection api in nodejs. But the image size should not be a restriction. Instead of resizing, you can crop your image and keep only the part that contain your object to be detected.
One approach will be like partition the image in 224x224 and run for all partitions but what if the object is between two partitions
The image does not need to be partitioned for it. When labelling the image, you will need to know the x, y coordinates (from the top left) and the w, h of the detected box. You only need to crop a part of the image that will contain the box. Cropping at the coordinates x - (224-w)/2, y- (224-h)/2 can be a good start. There are two issues with these coordinates:
the detected boxes will always be in the center, so the training will be biaised. To prevent it, a randomn factor can be used. x - (224-w)/r , y- (224-h)/r where r can be randomly taken from [1-10] for instance
if the detected boxes are bigger than 224 * 224 maybe you might first choose to resize the video keeping it ratio before cropping. In this case the boxe size (w, h) will need to be readjusted according to the scale used for the resizing
I have trouble getting Map behave properly when calling ZoomToResolution and PanTo
I need to be able to Zoom into specific coordinate and center map.
The only way I got it working is by removing animations:
this.MapControl.ZoomDuration = new TimeSpan(0);
this.MapControl.PanDuration = new TimeSpan(0);
Otherwise if I make call like this:
control.MapControl.ZoomToResolution(ZoomLevel);
control.MapControl.PanTo(MapPoint());
It does one or another (i.e. pan or zoom, but not both). If (after animation) I call this code second time (map already zoomed or panned to needed position/level) - it does second part.
Tried this:
control.MapControl.ZoomToResolution(ZoomLevel, MapPoint());
Same issue, internally it calls above commands
So, my only workaround right now is to set Zoom/Pan duration to 0. And it makes for bad UX when using mouse.
I also tried something like this:
this.MapControl.ZoomDuration = new TimeSpan(0);
this.MapControl.PanDuration = new TimeSpan(0);
control.MapControl.ZoomToResolution(ZoomLevel);
control.MapControl.PanTo(MapPoint());
this.MapControl.ZoomDuration = new TimeSpan(750);
this.MapControl.PanDuration = new TimeSpan(750);
Which seems to be working, but then mouse interaction becomes "crazy". Mouse scroll will make map jump and zoom to random places.
Is there known solution?
The problem is the second operation replaces the previous one. You would have to wait for one to complete before starting the next one. But that probably doesn't give the effect you want.
Instead zoom to an extent, and you'll get the desired behavior. If you don't have the extent but only center and resolution, you can create one using the following:
var zoomToExtent = new Envelope(point.X - resolution * MapControl.ActualWidth/2, point.Y, point.X + resolution * MapControl.ActualWidth/2, point.Y);
Btw it's a little confusing in your code that you call your resolution "ZoomLevel". I assume this is a map resolution, and not a level number right? The esri map control doesn't deal with service-specific levels, but is agnostic to the data's levels and uses a more generic "units per pixels" resolution value.
I'm using PostGIS on ruby/rails, and have created a simple box-like polygon under which I wish to search for land parcels in a county. The st_overlaps tool has worked for this before and it has worked this time, sort of.
So I created the polygon to search for parcels (multi-polygons, as it turns out) underneath it
factory = RGeo::Cartesian.factory
coords = [[1554780, 1101102], [1561921, 1062647], [1634713, 1097531], [1630867, 1140657]]
points = coords.map { |pair| RGeo::WKRep::WKTParser.new.parse("POINT (#{pair.first} #{pair.last})") }
ring = factory.linear_ring(points)
polygon = factory.polygon(ring)
After running the active record call:
Parcel.where{st_overlaps(:parcel_multipolygon, polygon)}
I get 157 results. Far less than expected. I exported them a kml file using a custom script of mine. I will upload it soon for viewing.
What you'll see in that kml once loaded in Google Earth, is a parallelogram of pins marking parcels whose areas (polygons) are clearly saddling the outer ring of the parameter-polygon I created to search under. There are so many parcels along these invisible lines in such a clear, distinct shape, the fact that there are no pins in the middle of the shape clearly indicate that the search results were only at the overlappings of parcel multipolygons with the exterior edges (LinearRing) of the search polygon.
Based on my re-reading of the documentation for st_overlaps, I'm left puzzled as to what seems to be the problem here.
Here's a link to view the kmz export. (coordinates converted to geographic before export). You can view it in your browser. The search-polygon itself is not included, but its easy to see where its exterior ring is
https://docs.google.com/file/d/0B5inC0VAuhH1TXdTbWQ2RngxZk0/edit?usp=sharing
I think it is behaving as expected. St_overlaps will give features that actually lie on top of each other. If you want all features inside the polygon try ST_Intersects.
I am programming a basic GUI in MATLAB that utilizes the mapping toolbox. The GUI will display a grayscale image and then plot discrete points over the data, all of this over the necessary map projection. It is important that I plot onto map axes (those created by the axesm command) rather than the vanilla cartesian space. I have no problem doing all this from the command line, but I cannot find a way to implement a GUI version and its driving me nuts.
The problem is that I need to specify the map axes as being the child of the parent figure. The normal axes has a property that can be set, doing something like:
axesHandle = axes('Parent', parentHandle, ...);
or
set(axesHandle, 'Parent', parentHandle);
However, there is no equivalent parent property for the map axes created by the axesm function, so I have no way to manipulate the axes within the figure. How can I do this?
Update: If I create a plot within the map axes in an empty figure, get(figureHandle, 'Children') returns the handle of the axesm object (thanks #slayton!), so the map axes object must be implicitly added to the children of the figure by MATLAB.
Should I be concerned that the map axes do not refer back to the parent figure, or should I just let it be? I wonder if this is a classic case of MATLAB forcing me to not comply with the standards the manual tells me to implement.
From reading your question what I think you are trying to do is grab the handle of the axes object. This can be done as the axes is created using either axes or subplot
a = axes();
a = subplot(x,y,z);
% both return an handle to the newly created axes object
Additionally if the axes is created automagically by a function call like plot or image you can get the axes handle that too:
p = plot(1:10); %returns a handle to a line object
a = get(p,'Parent');
i = image(); %returns a handle to an image object
a = get(i, 'Parent');
Finally, neither of those two options is available you can always get the axes handle from its containing figure with:
a = get(figureHandle, 'Children');
Remember though that this will return a vector of axes handles if your figure contains more than one axes.
Finally when it comes time to draw draw your points to the axes that contains your map image you simply need to call:
line(xPoints, yPoints, 'linestyle', 'none', 'marker', '.', 'color', 'r', 'size', 15)
This will draw the vertices of the line using large red dots.
I'm not sure if this answers your question because the code you provided doesn't line up with the question you asked.
The code you provided looks like you are trying to move an axes from one figure to another. You can totally do this!
f = figure('Position', [100 100 100 100]);
a = axes('Parent', f);
pause
f2 = figure('Position', [250 100 100 100]);
set(a,'Parent', f2);
After much trial and error and reading of documentation, I have found that there is no way to explicitly specify the parent of the map axes. Instead, they are implicitly added on top of the current axes. In the instance that no axes exist in the current figure, calling axesm creates an axes object and then places the axesm object inside. When you take this route, you have to grab the axes object handle by calling gca:
mapAxesHandle = axesm(...);
axesHandle = gca(...);
This makes it frustrating to use the mapping toolbox when writing a GUI from scratch, but that's the way Mathworks makes it happen. Thanks to #slayton for useful info. I'd upvote but my reputation is <15 :(
I am now working on an eye tracking project. In this project I am tracking eyes in a webcam video (resolution if 640X480).
I can locate and track the eye in every frame, but I need to locate the pupil. I read a lot of papers and most of them refer to Alan Yuille's deformable template method to extract and track the eye features. Can anyone help me with the code of this method in any languages (matlab/OpenCV)?
I have tried with different thresholds, but due to the low resolution in the eye regions, it does not work very well. I will really appreciate any kind of help regarding finding pupil or even iris in the video.
What you need to do is to convert your webcam to a Near-Infrared Cam. There are plenty of tutorials online for that. Try this.
A Image taken from an NIR cam will look something like this -
You can use OpenCV then to threshold.
Then use the Erode function.
After this fill the image with some color takeing a corner as the seed point.
Eliminate the holes and invert the image.
Use the distance transform to the nearest non-zero value.
Find the max-value's coordinate and draw a circle.
If you're still working on this, check out my OptimEyes project: https://github.com/LukeAllen/optimeyes
It uses Python with OpenCV, and works fairly well with images from a 640x480 webcam. You can check out the "Theory Paper" and demo video on that page also. (It was a class project at Stanford earlier this year; it's not very polished but we made some attempts to comment the code.)
Depending on the application for tracking the pupil I would find a bounding box for the eyes and then find the darkest pixel within that box.
Some psuedocode:
box left_location = findlefteye()
box right_location = findrighteye()
image_matrix left = image[left_location]
image_matrix right = image[right_location]
image_matrix average = left + right
pixel min = min(average)
pixel left_pupil = left_location.corner + min
pixel right_pupil = right_location.corner + min
In the first answer suggested by Anirudth...
Just apply the HoughCirles function after thresholding function (2nd step).
Then you can directly draw the circles around the pupil and using radius(r) and center of eye(x,y) you can easily find out the Center of Eye..