We are trying to create boundary maps of various zones in a city using Google maps or earth. Creating polygons for each zone makes the common boundary look different with zoom. Hence we are planning to create segments (shared boundary) with polylines. However, this requires joining multiple polylines (boundary segments) to create a zone (closed boundary) with properties of a polygon. I could not get any option where we can do this. Can anyone help us to address this problem?
Try looking into these links, it can be of help
Example:
http://gmaps-samples-v3.googlecode.com/svn/trunk/drawing/drawing-tools.html
Documentation:
https://developers.google.com/maps/documentation/javascript/overlays#drawing_tools
Related
I am using the Here API to search for roads where traffic accidents occur in my home town. My aim is to extract the full road coordinates (as sequence of of lat/lons) where the accident is active in order to draw that road on a reasonable scale.
Using the traffic/6.1/incidents API, I query for the data using a geographical bounding box. An accident in the response is described by one pair of TMC locations as well as one pair of lat/lon geographical points. This data is too coarse-grained for plotting the roadway. (Please correct me if I am wrong here, but I would like to add some more detail about turns of the road.)
My question regards what I found when I turned to examine the rest of the accident/incident response, containing so-called NAVTECH data on this (XML) form:
<NAVTECH><EDGE><EDGE_ID>1150578390</EDGE_ID><EDGE_ID>1150578391</EDGE_ID>
<EDGE_ID>...</EDGE_ID>
<VERSION_ID>201604</VERSION_ID></NAVTECH>
My question is: Is there any available method to map the NAVTECH edges to pairs of lat/lon coordinates?
I have searched Here.com, the here-api stackoverflow tag and tried to Google for an answer, but I find so little documentation on this type of data. I am looking for all information I can find to (i) Describe the NAVTECH edges and their meaning, (ii) How to map NAVTECH to geographical coordinates. In general, (iii) Can I use the Here API to get more geographical information than this about roads where there are accidents?
Kind regards,
Vilhelm from Sweden
You can pass a lat/lon to their routing API and get back the shape point coordinates (and other attributes) for the road edge at that location, like this:
https://route.cit.api.here.com/routing/7.2/getlinkinfo.xml?waypoint=43.066628,-71.471729&app_id=DemoAppId01082013GAL&app_code=AJKnXv84fjrb0KIHawS0Tg&linkattributes=all
Unfortunately, though, this may not be a long term solution, as seaBass states here:
getlinkinfo will depreciated March 31, 2017. In order to get speed limit information you will have to use PDE (Platform Data Extension) which requires an APP ID and Code
Ok, let me preface this question with the fact that I have created a lot of google maps, but they have been strictly markers and polylines denoting routes and a couple with some handler interaction.
Now I am looking to show basically a map of the world, mostly North America and I want to split this continent into my predefined regions with some lats/lngs that I have. Using these regions I want to draw something like a polygon with a light opacity and different color per region.
I then want to use marker clustering but I want the clusters to be specific to these regions. I have looked around but I haven't found an example like this. I have seen pages that say you can do this but not how you would go about doing this. Again, I am definitely a noob when it comes to drawing polygons and using the marker cluster. I know this question is fairly vague but just looking for an example/idea to start off of, and more so I don't want to write a bunch of code against this specific api and then find out that it is not possible.
Any ideas or suggestions are greatly appreciated....Thanks.
It can be done, but will require a rewrite of the MarkerClusterer (probably will simplify it).
You will need to determine how you are going to represent and load the cluster boundary polygons (KML, GeoJSON, native Google Maps API v3 polygons) and probably use the google.maps.geometry.poly.containsLocation(point:LatLng, polygon:Polygon) instead of LatLngBounds.contains to determine which cluster "owns" a marker.
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.
So what I'm trying to do is the following:
Have a map (such as Google Maps or questMaps). It doesn't matter at all which API I need to use.
On that map have an overlay on the streets. So say (for example) the street has bad lightning at night, it will be colored red. If it has good lightning it will have a green overlay.
Based on the overlay the map creates a custom route (for example the user only wants to walk on the green/well lit streets).
I have no idea how to accomplish this (especially step 3).
First, you'll have to decide what data you need. How do you categorize certain streets as lit or unlit? What if some parts of a street are well lit and some have no lights? Do you need to know the location of every streetlight in your area? What if lights burn out?
After figuring out what data you need, you need to build your dataset. I'd be VERY surprised if this data already exists, so you will probably need to gather it yourself. Either go around town and take notes, or crowdsource the project, or figure out some other way.
Once you have gathered your data, learn the drawing API of whatever mapping tool you wish to use. They all should have functions in their API for drawing colored lines (for streets) or points (for streetlights) on top of an existing map.
Finally, learn the navigational API of the mapping tool you chose. You're right, this is a hard step. I know Google Maps lets you specify certain waypoints when requesting directions; maybe your app can calculate well-lit waypoints and feed them to Google Maps' Directions service to influence the route it generates.
Good luck!
For custom routing, you need to read up on "Graph Theory". This ignores the geography of the street map, and considers it as a set of junctions (nodes or vertices in the graph theory jargon) connected by edges. You can assign weights to edges - these could be lengths, travel times, ones and zeroes etc. Anything. They can have no relation to the position on the map.
So for your application, you'd assign a large weight to unlit streets, and a small weight to lit streets, then use a standard minimum-weight algorithm to get a route from one node to another.
I have trouble finding any information on how to use the API to:
Search for streets and get some clickable results that returns a LatLng object or something (at least coordinates). So If I search for a street and click on a result, I'll pan to that street (for example).
How can I calculate distance between markers? and possibly, draw lines between them.
All I get is the API but no guides so it's fairly hard figuring out what types to use.
Here is a fiddle showing how this can be achieved:
http://jsfiddle.net/foxwisp/vQGMr/1/
To convert street names to lat/lng you need to use a Geocoder such as the one provided by Google Maps API.
Then, when you get back the results from the geocode, you use the lat lng properties to create a marker. Once your first marker is placed, you repeat the process for your second street address. We nest these calls so that we can be assured of the order of execution due to their asynchronous nature.
Once we have our second marker we use Google's polyline function to draw a line between the two latlng marker points.
Then we use a slightly complicated mathematical equation to do some distance calculations and voila.
The Google Maps API is fantastically documented, hopefully this fiddle will put it into context for you and you can explore each element step by step by reviewing functions and properties in the documentation