Newbie question.
Has anybody run into isoChrone (Drive Time Polygons) where the resulting points represent a self-intersecting polygon?
I presume this is to be expected with the algorithm and underlying network data?
I guess you mean the isoline calculation done by Here API. Do you have a specific scenario where you observe such a self intersecting ploygon ?
Related
I would like to draw a map of NYC where the distances between neighborhoods are scaled by transit time. I computed a distance matrix using the Google Maps Distance Matrix API for public transit.
To visualize it, I tried embedding using sklearn.manifold.MDS (metric MDS) and then making a scatter plot. This works kind of ok. Unfortunately, the axes are rescaled as part of this process, and I would like to provide a scale that reflects the raw transit time. In addition, the orientation of the points does not influence the fit, but for drawing a map, it would be nice if I could specify the orientation.
Does anyone have other methods that would be a better fit for my problem? I thought about fixing some reference points and using them to triangulate the remaining points on a map, but I don't know of an off-the-shelf way to do this.
I have a SpatialLinesDataFrame that is meant to represent survey tracks. These tracks are not strait lines where the route goes from a>b by the shortest distance, but instead the route twists and turns over its path (although no overlaps). My ultimate goal is to segment these curvy lines into specified distances, taking into account the twists and turns, to calculate presence/absence for each segment. Both in R and Arcmap I have segmented these lines, but it doesn't take into account the twists and turns along the path.
I believe the problem is that I need to convert the polylines into some kind of route class object, then segment that. Suggestions of how this can be done? Thanks in advance, Robin
What I'm looking forward is something like this:
I want the geographical(29 states points in the case) presented on the maps, with a mass amount users out side it.
All the examples I've found with leaflet package, igraph and ggmaps package is merely edges on maps or networks beside map. The only idea I have is to give the non geographical vertices a set of restricted lat/lon coordinates, for examples throw them to the Antarctic Pole.
I think there may be some method better to solve the problems.
I have Latitude and Longitude of a given point and I'd like to calculate the distance from this given point and some POIs (Point of Interest).
Moreover I'd like to use OSM (OpenStreetMap) and R.
Anyone can hel me?
Tnx
Have you looked into using the osmar project (http://osmar.r-forge.r-project.org/) for accessing POI data from OpenStreetMap? Here is a tutorial for using it - https://journal.r-project.org/archive/2013-1/eugster-schlesinger.pdf.
So, osmar will allow you to access POI data via an API and then you can use any standard R package for handling spatial data to get distances.
I am unable to find any documentation on how to do what has been accomplished on the map in the page of the link below. Does anyone know how this was accomplished?
Link to interactive map
The technology is called quadtree and quadkey. It uses a z curve to reduce the dimension complexity. Each quadrant is a part of a bigger map. The entire map is made of 21^4 tiles. Each tile has it unique address. You can also look for a geohash or Nick's spatial index quadtree hilbert curve blog. I've written a hilbert curve quadkey script in php at phpclasses org (hilbert-curve). It uses a script to transform a lat/lng pair to WSG 84 datum and compute a quadkey. For example you can use it for a fast proximity lookup.