I have a directed graph in Orientdb. When I connect it to Gephi, it is shown as an undirected graph. Why is it happening and how should I solve this?
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I'm creating an Blazor application for marketing research. The application reads the data from an API and I want to display a quite complex graph based on Chart.js.
In this graph I have same groups of data and stack bar charts.
I can quite replicate the graph with Chart.js but I don't know how to use it properly in Blazor. I saw few components like ChartJs.Blazor and its fork, Radzen components or Blazorize but none of them has a demo for a graph like that.
Is there any example or demo how to create complex graphs like that?
I have created and trained an object detection model in IBM Watson studio to detect a specific part of images. I was wondering how would I then extract that detected image and store it as a separate image? Is there something built into IBM Watson that does this or would I have to use something else to integrate the model with? If I do have to use something else, what would that be and how would I do it?
Thank you in advance!
IBM Watson doesn't have anything to do that extraction that I'm aware of. But a quick search showed a few utilities that can do that. The API returns the location of the detected object as a bounding box with X and Y positions and width and height.
I want to query openstreetmaps api for amenitys near a specified city / coords. So something like
Find all hospitals near denver, within a radius of 50km. The openstreetmaps API Documentation doesn't say anything about amenitys or i didn't found that.
Is this possible via REST and if yes, how?
For this kind of request, you'll likely want to use Overpass API, which is a read-only API that's designed for queries (unlike the main OSM API, also known as Editing API, which is mostly useful for contributing to OSM).
Overpass API supports an around filter.
Your example – hospitals in a 50 km radius around Denver – might look like this. (This is a link to Overpass Turbo, which is a frontend that lets helps with building and testing Overpass API queries. Note that the Geocoding in the example is a convenience feature of Overpass Turbo. For regular Overpass API queries, you'll need to provide either the coordinates or OSM element(s) you want to filter around.)
To build your query, you will want to know which OpenStreetMap tags correspond to the feature types you're interested in. The OpenStreetMap wiki provides documentation for most commonly used tags, e.g. amenity=hospital in this example.
I am building a navigation app using the Mapbox Direction API.
I want to obtain the OSM tag information along the route.
The tag information like speed limits, stop signs, traffic signals, number of lanes, one way, etc
Could anyone please help me?
If you have access to a backend, you can use OSM's Atlas tool:
Download an osm pbf file for the location you are looking at, for example from geofabrik.
Load the pbf into an Atlas object: https://github.com/osmlab/atlas#building-an-atlas-from-an-osmpbf-file Make sure to use a bounding box to save up memory.
Use the Atlas APIs to access the data: https://github.com/osmlab/atlas#using-atlas
Example: From a latitude/longitude use Location and then query using a small bounding box:
long osmIdentifier;
Location location;
atlas.edgesIntersecting(location.bounds().expand(Distance.ONE_METER))
.forEach(edge ->
{
if (edge.getOsmIdentifier() == osmIdentifier)
{
System.out.println(edge.getTags());
}
});
Does titan provide RDBMS trigger kind of thing that will be triggered whenever a new vertex or edge is added to the graph?
How will I know that a new vertex or edge was added to the graph?
Titan does not have a way to deal with that natively. You could, however, use EventGraph which is a graph wrapper over blueprints:
https://github.com/tinkerpop/blueprints/wiki/Event-Implementation
EvenGraph will pop off events to a listener that you write to gather the events.
EDIT: The above answer applies to TinkerPop 2.x and Titan 0.5.x and earlier. In Titan 1.x and TinkerPop 3.x one would rely on EventStrategy or Titan's Transaction Log.