In PHPMaster.com's latest tutorial Lukas White introduces you to using the Yahoo "Placemaker" web service to geographically locate a place from a free-form text string. The results include "place details" like the type of the location, latitude, longitude and how confident they are in their match.

The challenge then is to do two things: work out what place you could be talking about, disambiguate if necessary, and then identify exactly where on Earth that is. That's what I'll show you how to do in this article; by using a freely available web service, we'll write a simple program to ask users where they are (and ask them to clarify if necessary) before identifying their responses in concrete terms.

He shows how to make a request to the Placemaker web service, passing it a string coming from the user, to be located. The POST request contains a few pieces of data including an application ID , your desired output type and the language you're using for the input. His example code uses curl to make the request and handles it (the XML response at least) with a call to simplexml_load_string.

New on PHPMaster.com there's a tutorial from Lukas White about targeting users using geolocation based on the Geonames web service and a latitude/longitude. His example makes a call to find the closest "place" to the given coordinates.

Location-aware applications rely on being able to locate where you are, and this is what geolocation is all about. After all, once the application knows your location, it can go on to find the nearest store, guide you through the appropriate route to a destination, or target relevant advertisements to you. Geolocation, then, is simply the mechanism for identifying your geographical location.

He mentions two challenges associated with geolocation - finding where someone is and describing the location. With Geonames, he shows how to call the service's "findNearbyPlaceName" method to find the closest "place" to a given latitude/longitude combination. Included is a bit of sample PHP to connect to the service and Javascript to request the user's current location.

Derick Rethans has a new post today with a bit of code showing how to combine Flickr and OpenStreetMap and make a mapping tool that plots out the location information for the Flickr images.

I like taking pictures, and I usually take a GPS so that I can place them on a map on my Flickr page. On my last excursion however, the battery of my GPS had died, so I did not have location information available to store in my pictures' EXIF headers. Flickr can use the EXIF headers to then show the images on the map. Because I did not have the location information to automatically place my pictures on the map, I wanted to do that by hand.

His script (as used by a local Squid proxy) supports two different versions of the mapping - one for Yahoo! Maps and the other for OpenStreetMaps'. You can see the end result here - a set of Flickr images with a map in the background.

In a post earlier this month Timothy Boronczyk took a look at a common feature for web applications that's popping up more and more given the emphasis of social networking - geolocation of your users. The post shows you how to use various web services and data sets to determine where a user is and how they relate to other locations.

Services that allow users to identify nearby points of interest continue to grow in popularity. I'm sure we're all familiar with social websites that let you search for the profiles of people near a postal code, or mobile applications that use geolocation to identify Thai restaurants within walking distance. [...] The first step is to obtain the latitude and longitude coordinates of any locations you want to make searchable.

He talks about why postal code-based location isn't the best option, a web service (like Geocoder.ca for Canadians) could provide more accurate results. He includes code you can use to help search the data based off of two formulas - one to grab the larger area of locations and the other to filter them down into the closest. Finally, he shows how to use the Geolocation API service to get the results based on the user's search parameters.

In a recent post to his blog Dougal Campbell has posted about a geolocation plugin for WordPress that will let you automatically tag your posts based on here you are.

This Geolocation Plugin will be a nice addition for people who do travel blogging or who write about things in a particular area (restaurant and business reviews, hyperlocal news, etc).

The power of this plugin comes when you're using a device with a GPS in it (like an iPhone) that can feed the information into the plugin. The result is a link that users can hover over and get a map of the location.