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.
Related
When I am searching "Rudy barber Shop, New York" string in http://maps.google.com, google map showing 10 results...
But When I am using google map api in my App, It only returning two results
http://maps.googleapis.com/maps/api/geocode/xml?address=Rudy%20barber%20Shop,%20New%20York&sensor=false
Now my question is that how can get the same result.
Thanks
Mandeepd
I don't think you can get exactly the same results as in Google Maps.
Google Maps is a whole application. It uses multiple kinds of search engines behind the scenes and some may not be available as APIs, e.g. transit (public transport) directions.
Your sample request shows that you are using The Google Geocoding API which is meant for converting addresses (like "1600 Amphitheatre Parkway, Mountain View, CA") into geographic coordinates. This only works for addresses, not businesses. When you put a business name in front of the address, the Geocoding API still tries to figure out where that may be, based on the part of your query that looks like an address. However, the Geocoding API is not meant for that use.
If you are after searching businesses around a given location, maybe you could use the The Google Places API (Experimental) but make sure to comply with its Requirements.
I'm looking for a solution to be able determine landscape type by a given coordinate, for example check if current position is water/forest/town/road and so on. I found google.maps.MapTypeStyleElementType object specification in the Google Maps specification, but not sure if it could help me or not.
Probably, there are some another Maps API with such functioality? Or maybe I should refer to the different types of offline maps?
Nope, the link you send is just for styling the proper features, not to tell which feature is at a given coordinate. If you are interested in landscape, then Corine Land Cover is the thing you are looking for. It describes the types of biotops like forest, water, but also land use - meadow, field, buildings etc. However, I don't know if there is such an online service where you could query particular coordinates. Other solution for you would be to import these GIS layers (they are freely available) to your own gis map server. Maybe this is partially solved as there are e.g. projects how to incorporate these into openstreetmap.
Well not quite, but you could get close to what you're looking for by using the Google Reverse Geocoder and the Google Places API
Google Reverse Geocoding
http://code.google.com/apis/maps/documentation/geocoding/#ReverseGeocoding
If you send the service a geocode it will send back an address type and/or one of several adress components http://code.google.com/apis/maps/documentation/geocoding/#Types
Google Places API
http://code.google.com/apis/maps/documentation/places/
You could use the Google places API to search for for what's near. If the geocode is in the middle of the lake, the Places API may return something like "Lake Michigan" and then you'd know the terrain obviously.
all, which google map API could be use for search nearby business spot information like ATM/Branch (address and coordinates information etc)
thanks for help
This service is provided by Google as part of their Places API. As of today, it is only a developer preview, and you must have an Adsense account to register.
A search request will return up to 20 establishments, which indicate their type, so they can be filtered. There seems to be no way to perform a more direct search by type for now.
I'm trying to use Google Geocoding API, but i keep on getting a very inaccurate answer (off by 3.2 KM).
Here is an example:
http://maps.google.com/maps/api/geocode/json?sensor=true&address=Hava%27ad+Haleumi+21+Jerusalem
I get the coordinate 31.7857,35.2007.
Ff you look up "Hava'ad Haleumi 21 Jerusalem" in maps.google.com, you can see that the location is 3.2KM away from what Google Geocoding API gave me.
Does anyone know why this happens?
Thank you.
Actually, the Google Maps API does not support geocoding in Israel beyond city level, so your solution is to do what you did and finding an alternate geocoding service.
The reason you got the correct location when searching on maps.google.com is because the API uses a different provider than maps.google.com due to licensing issues.
Here is a spreadsheet detailing the coverage area for Google Maps.
It's possible to use waze.co.il instead of google:
Their JSON API is
http://www.waze.co.il/WAS/mozi?q=yourAddress&token=yourToken
(Also, as stated in this thread http://www.waze.co.il/forum/viewtopic.php?f=21&t=6113
reverse geocoding is a paid service.)
Take a look at the response. You are getting a partial match and the location type is approximate. If you look at the veiwport you will probably find that the location you are looking for falls within that viewport. *Edit - Actually it looks like it just matched to city - Jersulem in this case - which is why you are probably off by so far
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.