I have some csv files of latitude/ longitude points and I want to draw some maps using Here.
Points,Latitude,Longitude
Start_Point,37.8279,23.80773
Point_7,37.83347,23.80042
Point_6,37.83374,23.80056
I want to be able to see the directions from point A to point B on road.
I have uploaded the csv via "Your Geospace" but seems like I don't have access to GPX traces on support layers. Is this available only when you upload GPX files?
Is there a way not to only draw the points on map, but draw the whole route. I want something like a travelling salesman problem.
We have HERE TCS examples page https://tcs.ext.here.com , https://tcs.ext.here.com/examples/v3.1/ where you can find how to develop your applications - just mouse right click on an example and select 'View page source'
We have RME API (Route Match Extension) where you can upload your GPS coordinates in CSV format: https://tcs.ext.here.com/examples/v3.1/rme_basic - this example makes a route match the points and calculate a route with showing on the map.
Travelling salesman problem you can resolve with HERE APIs:
HERE WSE API (Waypoints Sequence)
https://developer.here.com/documentation/routing-waypoints/dev_guide/index.html
HERE Tour Planning API - https://developer.here.com/documentation/tour-planning/2.3.0/dev_guide/index.html
Related
I want to write an application that gives me the exact route of a subway.
When you use Google Maps it just connects two stops linearly, but not the actual way.
Is there a way to move a route anywhere on a map without being bound to roads?
If there's any solution (doesn't have to be with the Google Maps API) please let me know.
Edit:
Example
Google shows the train route like the brown line, but the train actually drives the blue line. What I would like to do is get the blue line so that I can get the coordinates of the route and calculate the curves and elevation.
I know that I could add like 50 waypoint and get get a "fake" route with them, but I would like to have it automatic and not done by hand.
To show the transit directions (subway, bus, tram, etc.) Google Maps uses the data provided by transit agencies in the form of GTFS feeds. This is a responsibility of the agency to provide a detailed shape of the route for the transport according to the GTFS specification. You can have a look at GTFS documentation to figure out how does it work:
https://developers.google.com/transit/gtfs/
https://developers.google.com/transit/gtfs/reference/#general_transit_feed_specification_reference
I hope this helps.
I'm using the Here.com "maptile" api to populate my map with map tiles. Now I want to add routes from point A to B to the map. I figured Here's routing api would provide me with a nice set of coordinates to use for plotting a line in the map, but the api only provides one coordinate pair per "maneuver" (that is, at roundabouts, exits, intersections etc). That is not detailed enough to use for plotting routes since all roads are not perfectly straight ;)
Example
This example at Here's api playground shows a red route plotted perfectly along a road using their map image api. However, if you run the start and end coordinates in the "m1" field through the routing api, you will get the following coordinates:
52.5408395,13.2626364,52.5403011,13.2630944,52.5289285,13.2687593,52.51873,13.2800306
If you enter these coordinates in the "r1" field and click Send Request, you will see that the route is plotted differently (straight line across the park, instead of along the yellow road).
Question
Is there any way to get more detailed data from Here.com's routing api (or any other Here api I may have overlooked), suitable for plotting roads?
Or is there perhaps some way to get map tiles from the maptile api with a route properly pre-rendered?
In HERE Routing API, you can ask for route shape with parameter &routeattributes=shape
This will return an array of coordinates which represents the exact shape of the route on the road. You can also use pedestrian mode which will take into account the roads only accessible on foot.
Unfortunately it's not possible to get map tiles with rendered route shape using Map Tiles API. This API is just for fetching tiles.
I am working with a security company that has a patrol car travel around a neighborhood. Every 30 seconds, they record a GPS coordinate/point which I can download and use. I'm trying to map a 'path of travel' for the patrol vehicle using Google Maps API.
I understand how to map (marker) all the points using the Google Maps v3 API. I also understand how I can do a driving route between a few points using directionsService. According to Google and StackOverflow, the maximum number of waypoints is 26.
The problem is that I have dozens of these points (1 hour = 120 points). I can't just draw a polyline between the points because I need it to show the path of travel on the actual street - not as the crow flies between 2 points. Also, I don't have 10K to purchase an Enterprise license.
Any ideas on how this might be accomplished or am I SOL? Can you draw 120 multiple 'routes' on the same map? Speed is not important here.
Thanks,
Mike
Can you draw 120 multiple 'routes' on the same map?
You can. When you want to draw the routes by using the DirectionsRenderer you must use a separate DirectionsRenderer-instance for each route.
Another approach: request the routes via the DirectionsService, but use a custom Polyline to draw the route. Each time you get a new route you'll only have to push the points of the new route to the path of the polyline.
I need a polygon for every German state. I go all the GeoPoints in one JavaScript-file but the file is because of the amout of points about 4MB. I've been googling and thinking about this problem all day but couldn't figure out a solution...
How can I use Google Maps polygons without forcing the user to download a huge js-file with the coordinates?
Thanks!
Ron
You can encode the polygon points to vastly reduce the size of the javascript file. To do this, you must include the geometry library.
https://developers.google.com/maps/documentation/javascript/reference#encoding
https://developers.google.com/maps/documentation/javascript/geometry#Encoding
One option is to use a FusionTablesLayer to display the polygons. They are available in the Natural Earth data set that is publicly available.
Example
You could do the same with your points and a KmlLayer if you convert your data to KML.
Well... somehow the points have to get to the user. You could think of the following solutions to reduce the data usage:
Use different polygons for different zoom levels. For example zoomed out you won't need the full details.
only send parts of your polygon back to the user. You can for example send the viewport coordinates to an AJAX script. This one queries your database and/or shapefile and only returns the polygon parts that are visible in the user's viewport
preprocess tiles. If you can generate images from your shape, you can overlay these on Google Maps.
I am looking for advice for an application I am developing that uses Google Map.
Summary:
A user has a list of criteria for searching a street segment that fulfills the criteria. The street segments will be colored with 3 colors for showing those below average, average and over average. Then the user clicks on the street segment to see an information window showing the properties of that specific segment hiding those not selected until he/she closes the window and other polyline becomes visible again. This looks quite like the Monopoly City Streets game Hasbro made some month ago the difference being I do not use Flash, I can’t use Open Street Map because it doesn’t list street segment (if it does the IDs won’t be the same anyway) and I do not have to show Google sketch building over.
Information:
I have a database of street segments with IDs, polyline points and centroid.
The database has 6,000,000 street segment records in it. To narrow the generated data a bit we focus on city. The largest city we must show has 250,000 street segments. This means 250,000 line segment polyline to show.
Our longest polyline uses 9600 characters which is stored in two 8000 varchar columns in SQL Server 2008.
We need to use the API v3 because it is faster than the API v2 and the application will be ported to iPhone. For now it's an ASP.NET 3.5 with SQl Server 2008 application.
Performance is a priority.
Problems:
Most of the demo projects that do this are made with API v2. So besides tutorial on the Google API v3 reference page I have nothing to compare performance or technology use to achieve my goal.
There is no available .NET wrapper for the API v3 yet.
Generating a 250,000 line segment polyline creates a heavy file which takes time to transfer and parse. (I have found a demo of one polyline of 390,000 points. I think the encoder would be far less efficient with more polylines with less points since there will be less rounding.)
Since streets segments are shown based on criteria, polylines must be dynamically created and cache can't be used.
Some thoughts:
KML/KMZ:
Pros:
Since it is a standard we can easily load Bing maps, Yahoo! maps, Google maps, Google Earth, with the same KML file. The data generation would be the same.
Cons:
LineString in KML cannot be encoded polyline like the Google map API can handle. So it would probably be bigger and slower to display. Zipping the file at the size it will take more processing time and require the client side to uncompress the data and I am not quite sure with 250,000 data how an iPhone would handle this and how a server would handle 40 users browsing at the same time.
JavaScript file:
Pros:
JavaScript file can have encoded polyline and would significantly reduce the file to transfer.
Cons:
Have to create my own stripped version of API v3 to add overlays, create polyline, etc. It is more complex than just create a KML file and point to the source.
GeoRSS:
This option isn't adapted for my needs I think, but I could be wrong.
MapServer:
I saw some post suggesting using MapServer to generate overlays. Not quite sure for the connection with our database and the performance it would give. Plus it requires a plugin for generating KML. It seems to me that it wouldn't allow me to do better than creating my own KML or JavaScript file. Maintenance would be simpler without.
Monopoly City Streets:
The game is now over, but for those who know what I am talking about Monopoly City Streets was showing at max zoom level only the streets that the centroid was inside the Bounds of the window. Moving the map was sending request to the server for the new streets to show. While I think this was ingenious, I have no idea how to implement something similar. The only thing I thought about was to compare if the long was inside the bound of map area X and same with Y. While this could improve performance significantly at high zoom level, this would give nothing when showing a whole city.
Clustering:
While cluster is awesome for marker, it seems we cannot cluster polylines. I would have liked something like MarkerClusterer for polylines and be able to cluster by my 3 polyline colors. This will probably stay as a “would have been freaking awesome but forget it”.
Arrow:
I will have in a future version to show a direction for the polyline and will have to show an arrow at the centroid. Loading an image or marker will only double my data so creating a custom overlay will probably be my only option. I have found that demo for something similar I would like to achieve. Unfortunately, the demo is very slow, but I only wish to show 1 arrow per polyline and not multiple like the demo. This functionality will depend on the format of data since I don't think KML support custom overlays.
Criteria:
While the application is done with ASP.NET 3.5, the port to the iPhone won't use the web to show the application and be limited in screen size for selecting the criteria. This is why I was more orienting on a service or page generating the file based on criteria passed in parameters. The service would than generate the file I need to display the polylines on the map. I could also create an aspx page that does this. The aspx page is more documented than the service way. There should be a reason.
Questions:
Should I create a web service to returns the street segments file or create an aspx page that return the file?
Should I create a JavaScript file with encoded polyline or a KML with longitude/latitude based on the fact that maximum longitude/latitude polyline have 9600 characters and I have to render maximum 250,000 line segment polyline. Or should I go with a MapServer that generate the overlay?
Will I be able to display simple arrow on the polyline on the next version.
In case of KML generation is it faster to create the file with XDocument, XmlDocument, XmlWriter and this manually or just serialize the street segment in the stream?
This is more a brainstorming Stack Overflow question than an actual code problem. Any answer helping narrow the possibilities is as good as someone having all the knowledge to point me out a better choice.
Large numbers of short GPolylines run massively slower than small numbers of long GPolylines.
The speed difference between Google Maps v2 and Google Maps v3 is not going to be significant, because most of the CPU time will be taken up by the actual graphics system of the browser. Google Maps uses the VML, SVG or Canvas graphics systems, depending on the browser. Of these, VML is by far the slowest, and that gets used whenever the browser is MSIE.
Before embarking on tackling 250,000 line segments, I suggest you take a look at this quick speed test of 200 random polylines. Try zooming and paning that map in MSIE.
Then, also consider the amount of data that needs to be sent from the server to the client to specify 250,000 line segments. The amount of data will vary depending on whether you choose KML or JSON or GeoRSS, but if you end up with 20 bytes per line segment that would take 50 seconds to fetch on a 1 megabit broadband connection. Consider whether your users would be prepared to sit around for 50 seconds.
The only solution that really makes sense is to do what Google do for their traffic overlay, and draw the lines onto tiles in the server, and have those tiles be displayed as a GTileLayerOverlay in the client.
What you need is a spatially aware database, and a server-side graphics library like gd or ImageMagik. The client asks for a tile from the server. If the zoom is above a certain level the server scans the database for line segments that have bounding boxes that overlap the bounding box of the requested tile and use the graphics library to draw them.
The zoom level limit is there to limit the amount of work that your database and server needs to do. You don't want to end up drawing 250,000 line segments onto a single zoomed out tile because that's an awful lot of hard work for the server, and isn't going to mean very much to the user.
Regarding click handling:
The easy thing to do is to listen for clicks on the map, rather than on the objects, and send the click details to a server. The server then uses the click location to search the spatially aware database and returns the details of the clicked object if there is one. The client code does this:
GEvent.addListener(map,"click",function(overlay,point) {
var url="clickserver.php?lat=" + point.lat() + "&lng=" +point.lng();
GDownloadUrl(url, function(html) {
if (html.length) {
map.openInfoWindow(html)
}
});
});
The harder thing to do is to handle the changing of the cursor when the pointer is over the polylines. There's a known technique for doing cursor changes for small markers, which works like this:
Whenever a tile is fetched, the .getTileUrl() also makes a call to a server that returns a list of hotspot boxes for that tile. As the mouse moves, the client constantly calculates which tile the mouse is over, and then scans the corresponding list of hotspot boxes.
Google themselves, in their GLayer() code, add the sophistication of performing a quadtree search to speed up the search for hotspots within a tile, but other people who have implemented this strategy in their own code reckon that's not necessary, and a linear scan of the hotspot list is fast enough.
I've no idea how to extend that to handling cursor over polyline detection.