I have 2 custom long-lat data sources, one for area polygon, and one for point data as follows:
area polygon data
point data
I tried to map them on tableau using instructions on https://onlinehelp.tableau.com/current/pro/desktop/en-us/maps_dualaxis.htm
, but I cannot get the spread-ed point data on the second layer. all I get is one point.
output
Using OSRM API, I found the coordinates of the intersections along a route.
I want to know what are the corresponding node IDs.
Is there any API to find the node IDS from the coordinate points?
Is there any API to find the node IDS from the coordinate points?
Yes. You need to pass annotations=nodes as additional query parameter. routes[i].legs[j].annotations.nodes will be an array of OSM IDs that you can use to link the data with OSM.
Linking this to the coordinates in the step is a little bit complicated: You would need to concatenate all RouteStep.geometry and remove the duplicated coordinates (steps[i].geometry[-1] == steps[i+1].geometry[0]).
Can anybody get me with how to add multiple markers to a leaflet map using geocoding ? There are two parts which I wish to implement.
First part is that can I place markers on the map based on the address of each marker instead of latitude and longitude in the data file which is in .json format?
The next part is, once the address is placed on the map using geocoding, can I retrieve the latitude and longitude of the markers using reverse geocoding and store in a file?
Kindly help me with these queries.
I need a framework which takes a set of latitude longitude points and plots on a world map, grouped by country having the count of points as a marker on each country. Grouping here is the count of latitude longitude points in a country.
And as I drill down into a country, the clustering should change to state based one. And the next level, to districts.
Leaflet marker cluster is something very similar to what I have asked for, but the grouping is based on proximity and it doesn't consider country or state boundaries. That is, they are not region aware.
Regionbound.com has tweaked in some code in the leaflet code for making it region aware,
Sample marker definition:
var marker1 = new L.marker([-37.8, 145], {regions: ["Asia-Pac", "Australia", "VIC", "Melbourne"]} );
But the sample code says, every latitude longitude must be defined along with some extra parameter containing place information.
I could get the place information using reverse geocoding, but reverse geocoding every latitude longitude is time consuming right.
Highmaps provided by Highcharts is one another solution, but there, every country has code which should be assigned a value[count of point coordinates belonging to that country].
But all I have is latitude longitude points, no country or state information.
Thus, I need something which takes only a set of latitude longitude and does clustering based on country, state, district depending on the zoom level.
You have 2 separate needs in your questions:
Map your lat/lng coordinates to appropriate administrative areas. E.g. through the reverse geocoding that you mention.
Display "clusters" on those administrative areas depending on zoom level.
As for point 1, you know that lat/lng points do not say by themselves which administrative area(s) they belong to. So "reverse geocoding every latitude longitude" is a mandatory step. Whether time consuming or not depends on the solution you choose to perform this operation.
If I understand correctly, you would like a "framework" that could do that automatically for you. But frameworks are usually data agnostic, and if they do not have data about boundaries of those administrative areas, they cannot help you.
You may rather look for "services" (like the Mapbox Geocoding API that you mention) or software that would already have such data. It is not time consuming if you can program the lookup (or perform "bulk" operations) and if you are not limited by the requests rate and your amount of points to map (which may be the case with Mapbox).
You could very well set up your own application to perform this mapping:
As for the dataset for administrative areas boundaries, you would probably be interested in links in this post: Are there any free administrative boundaries available as shapefiles? If your points are limited to a few countries, it will be easier for you to find the appropriate data source(s).
Once you have that data, many GIS software should be capable of mapping your lat/lng points to the areas they belong to. This would be mainly for a "one-shot" operation, if your set of points do not change much.
A "web-compatible" alternative would be for example to use Leaflet with point in polygon for Leaflet plugin. You would need your boundaries data converted to GeoJSON format first. Again, GIS software should be capable of doing so, or many online services as well (search for "convert geojson" for example).
A server-side solution would avoid having to manage the entire boundaries data through network and in client browser (if you need to perform the mapping dynamically). I am sure many GIS servers are capable of performing this operation, once they are fed with the boundaries data.
For point 2, once you have completed the above step, I think you would have many options available, including those you mention (RegionBound, Highmaps).
Even with standard mapping libraries (Leaflet, OpenLayers 3), you would just need to build your "clusters" (markers on administrative areas with a number saying how many points are in there), like you have to do with Highmaps anyway for example.
Computing the number of "clustered" point is as easy as filtering your points per area name / code. Then switch the clusters to the desired administrative level when the map zoom changes.
So the key is really to determine first to which areas your points belong to (point 1).
Then a small question would rise about where to place the "cluster" marker:
On centroid of the administrative area? You need the coordinates of that centroid from your data source, or a good algorithm to compute it from the boundaries (good luck on that…).
On "center" of the bounding box of the area? Leaflet can easily compute that: from your area vector shape, you would do myShape.getBounds().getCenter().
On barycentre / centroid of the clustered points? This is what Leaflet.markercluster and RegionBound do (do not know for Highmaps).
Good luck!
I drop a pin in an MKMapView with longitude and latitude. When I place same longitude and latitude on google map the pin on both are slightly different.
I have a web/iPhone app that renders a map for positions sourced from the same database and haven't seen this issue. I would check your assumptions:
Are you truncating your values over the wire?
Are you rounding the position values differently on the two platforms?
Check the values you are passing into Google Maps and MapKit by logging them and comparing.
You can see from the following screenshots that the same latitude/longitude are rendered on the same position on the map:
Update
I tried the coordinates you mentioned in the comments and got the same position for both. You need to check your assumptions. The values that you are using on the web or on the device are not the values you think they are: