Sat, 16 Sep 06
Comments on upgrading to version two of Google Maps
I recently upgraded a simple simple Google Map that I built last spring to display some of the cross country skiing around Boulder. You can see the original version here. I built this based on this XML.com article, using XMLHttpRequest to retrieve the data from the server and Gmarker.openInfoWindoXSLT() with this XSL stylesheet to present the data.
I decided to upgrade this map last week to version two. Since openInfoWindowXSLT is no longer supported on every browser, I feared that the upgrade would take significant effort, even though the map very simple. However, the upgrade ended up being easier than I thought it would be. To get started, I read the Google Upgrade Guide–this document explains just what changes were made in the API. The changes that affected my map included:
- A few method name changes–
centerAndZoombecomessetCenter GPointis no longer used to indicate a latitude and longitude location on a map, and its replacement,GLatLng, reverses the order of the constructor’s arguments.- Zoom levels are flipped around, with larger numbers now signifying higher resolutions
- The biggest effort was modifing the code not to use the XSLT process for generating infoWindows. However, this was easier than I thought it would be. I simply wrote a javascript method that mimicked what the XSL had previously done. Sure, accessing the DOM elements was a bit of a hassle that required some debugging (that’s the win of XSL–declarative DOM access), but the alternatives were either ignore browsers that don’t have built-in XSLT support (Safari) or integrate AJAXSLT, a Google sponsored project to provide cross browser XSLT support. If this were a larger project that depended on more XSLT, I probably would have done the latter.
Upgrading my (admittedly very simple map) took about 1.5 hours. Visit the new map and take a look at the code.
Technorati Tags: google maps upgrade
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Andrew Collins said,
September 19, 2006 at 4:35 pm
The Examples page contains a few asynchronous event processing scenarios.
In particular, look at Example 12 - Asynchronous Events which contains an EventListener bean that can access the Request object, allowing a Cookie to be set.