What is the best way to plot points on a Google map? I have a bunch of addresses (about 300) stored in my database, and right now I am outputting each address into a JS array and plotting each address by looping over the array and running a function that geocodes the address and creates a new marker. However, I'm not sure if that is the best approach. Any thoughts?
Your problem is the geocoding part. Geocoding 300 addresses in one go is slow, and you would quickly hit the daily limit.
You should consider doing the geocoding on the server-side, and caching them in your database, or somewhere else. The Google Maps API Terms of Use appear to permit the caching of geocoding results "for the purpose of improving the performance of your Maps API Implementation" (Section 10.3).
If the addresses are relatively constant, then the repeated geocoding isn't terribly efficient. You could geocode each once and submit to Google Maps only the latitude and longitude for plotting. See the KML upload information.
What I ended up doing was geocoding the addresses upon address insertion into my databas using a web service called Tiny Geocoder: http://tinygeocoder.com/.
For the existing addresses I already had, I ran a script that used this same service to loop over my result set, geocode each address, and store the lat/long in the database. It took awhile but it got the job done.
Related
I have a Google spreadsheet with one column of physical addresses, and I want to have a second column be the time in minutes to walk between the address in column 1 and a second address (as determined by Google Maps). Any recommendations on how to accomplish this task?
From my understanding of the Google Maps terms of service, they:
don't like people using their service as a "batch geocoder". This means that
you will need to throttle your requests (place delays between each successive request, to avoid the OVER_QUERY_LIMIT error)
it is against the terms of service to use the geocoder (and maybe the distance service) without displaying a map graphic
If you still want to proceed,
you need some way of extracting the address from your spreadsheet. I think there's a Google docs API that will help you do that. I also found some custom Javascript code that does that for you easily. I don't have a link anymore :(
once you have the addresses readable from the Google Maps Javascript API, you can call the distance or directions API to get the walking distance
then you need to save that back to the spreadsheet.
It sounds like a possible application for the Distance Matrix Service.
But you can only use it if you will be displaying a map
Use of the Distance Matrix API must relate to the display of
information on a Google Map; for example, to determine
origin-destination pairs that fall within a specific driving time from
one another, before requesting and displaying those destinations on a
map. Use of the service in an application that doesn't display a
Google map is prohibited.
Google Maps API has any way to get the street coordinates of an location?
Is simple: I just want to get the nearest street coordinate. To got this i need, for example, all coordinates that compose a street.
Are there something like this?
You may use the directionService.
Pass the given address(or location) as origin and destination to directionsService.route() and use the travelMode DRIVING . The response should contain the nearest street.
Demo: http://jsfiddle.net/doktormolle/W3VGN/
I found this (ReverseGeocoding in v3): https://developers.google.com/maps/documentation/javascript/geocoding#ReverseGeocoding
Since this thread is old I suppose this could be useful.
These answers are all old, and Google has rearranged the maps API significantly since the answers.
In 2018, the best way to turn a location (long, lat) into a "point on road," is to use the snap-to-road or nearest-road service:
https://developers.google.com/maps/documentation/roads/snap
Note that this API charges a cent per API call, and can take up to 100 distinct points per call. If latency and complexity aren't problems, if you need to answer this question on a client, you could build a server that collects up to 100 requests from different clients, makes one request to Google, and then returns the request data back to the appropriate clients. (For this use, make sure to use nearest-road, not snap-to-road.)
Also, currently, Google Maps has a $200 per-month statement credit available, which may make smaller uses of this API not actually end up costing much (or anything at all.)
I want to label around 300K addresses according to their longitudes and latitudes on the google map. By labeling, I mean put an indication sign on the map.
Are there any methods to realize it? Thank you.
Best,
Leon
If you mean you have full, proper addresses and you want to geocode them (find lat/lngs) then consider using Google Fusion Tables - its like a spreadsheet to which you can define a location field.
Then, you can tell Google Fusion Tables to geocode those addresses for you and it fills in the lat/lng location, and creates a kml file from this with "infoboxes" which you can define.
The geocoding process should be seen as one-off operation, and may take somewhere between many minutes and many hours to do this work.
Use the geocoding api
It is easy to use the Google Maps API to find a specific street address and return the latitude and longitude. For example, link.
However, it appears that typing in the name of a specific location, for example a park, causes problems. Often these don't have a specific street number (at least, not easily findable). Despite the fact that Cadigal Reserve is located at the same address as in the link above, if I enter that as part of the query string and remove the street number, the results become rather useless: link
Typing this directly into maps.google.com easily finds the park itself (and of course, you could then find the latitude/longitude by looking in the URL).
Is there not any way of using the Google Maps API to geocode a park location like this?
It is important to understand that geocoding is not an exact science. The recommended practice if you have addresses that you know should geocode to a specific location is to build a cache and use local (client-side) geocoding.
In version 2 of the api you would build your own client-side cache that contains pre-computed geocoder responses by extending the GeocodeCache. Once a cache is defined, you would call the setCache() method and away you go. This is pretty much explained here:
http://code.google.com/apis/maps/documentation/javascript/v2/services.html#Geocoding_Caching
However, AFAIK GeocodeCache was removed in V3 of the api...
So, I would suggest implementing your own client -side caching-strategy of known addresses and their corresponding coordinates. When your application receives a geocode request for a known address the response would come from your cache (rather than Google's geocoding servers).
Failing all that you can always use a payed geocoding service that, in theory, will have a much more accurate dataset (as well as a higher limit on requests, etc).
Finally, you should also take a look through the Geocoding Strategies document as it gives a good handle on some of the issues here.
When I type in addresses in Google maps for locations in Asia, quite a lot of them are off by more than 200 metres. For example, "blk 85 bedok north road, singapore" is off by more than 300 metres. While I don't expect Google Maps to be spot on every time, sometimes the error is too great for certain use cases. What options do I have to handle inaccurate Google Maps locations in a web app? The web app should let the user enter an address or postal code as part of an entry and I will geocode the address and store the lat-long.
You could use bing, yahoo's and google's Geo Location api's to find latitude and longitude for a location, average the results together and use the result. Thus, if they all agree, you still get a good location, but if they disagree you get the best approximation of all three.
You could even programmatically compare the results from each engine and throw out any that don't agree with the others (for instance, if bing and yahoo agree and google does not, you could throw out google).
Beyond that, if you have a collection of addresses you know to be wrong, you could simply store the correct longitude and latitude for those points, and override the results in those cases.
Of course, to get around this problem at all, you'll need to geocode the addresses, check their validity in some way (as described above), and plot them using their latitude and longitude.
You don't have any fixes for this really, you're at the mercy of the accuracy of google maps here. The important part is you don't know if the address in inaccurate when doing one search to the next, so nothing you can do to handle it.
You can post a topic here and google will see it and often respond as well: Google Maps Local Listing Forums. I'd open something there with some of your examples and hope they get more accurate...that's all you can do in this case.
There are always other alternatives as well, yahoo and bing have mapping APIs, but I have no idea how much better or worse off you'd be going that route.
The problem is not the lat/lng data, in fact, they are correct. The problem is that the geo coords of the map tiles of the public Google maps api are inaccurate. The maps at maps.google.com are provided by a different map provider than the map tiles used with the public Google Maps API that you can embed in your website, use in your own applications, etc.
Check my recent posting at Google Maps & apps with mapview have different current positions
Is the result out on maps.google.com as well as through the maps api?
If on google maps live site the result is accurate then you can do an ajax search to return the correct lon/lat.
I have used this when geocoding UK postcodes
Geocoding UK Postcodes with Google Map API
I tried to reply to the upper answer, but I am not qualified enough yet. Just be aware that whatever you're using for geocoding, sometimes has restrictions on the use of that data. For example, google's geocoding API isn't allowed to be used to display information retrieved anywhere but google maps. The same might be for the others, I don't know what your project is, but it's something to be aware of.