Paddyworks.com »technotes

I’ve recently been working on some Model-View-Controller software for PHP that I’ve dubbed MirageVC. I wanted a subversion repository that I could access from anywhere, so I requested some project space at Sourceforge. It was accepted. Hurray! Here are a couple of URLs:

Main project website:
http://miragevc.paddyworks.com

Sourceforge project page:
http://sourceforge.net/projects/miragevc

For some reason I only recently got excited by the web geography phenomenon – i.e. GeoUrl and GeoUrl.info. I think for a long time I was fairly concerned with preserving a sense of anonymity with regards to my presence on the web; or perhaps with maintaining a distinction between my web identity and my personal identity. And while nearly the entire history of my professional career can be revealed by Google and other internet tools, somehow attaching my coordinates to a web site seemed a little too much like rolling over for Big Brother.

And so rather than thinking that broadcasting my coordinates across the ether was an interesting idea or had any real merit – much less that it could have some pretty cool applications – I preferred to remain sheltered behind a half-imagined sense of privacy that comes with publishing information in name only.

But somehow I’ve recently had a change of heart. Perhaps it’s because publishing on the web somehow generates a certain desire for notoriety. Perhaps it’s related to the fact that in the past year, even the past month, location has exploded in popularity as a focus of new web technologies – take Google Maps and Memory Maps on Flickr as evidence of this.

Whatever the reason, a few weeks ago I added GeoUrl meta tags to a couple of my websites. And then I more or less forgot about it.

Until a little while ago.

I was skimming through the referring URLs from the log of my personal blog when I noticed a hit from http://brainoff.com/geoblog/. I thought to myself, Hmmm, that’s an interesting URL, and went to check it out.

Wow! What a cool tool. Geoblogs is this: A near-realtime worldmap of geo-indexed blogs that updates as they ping Weblogs.com. Wow! And it’s built using worldKit, a light-weight Flash tool by Mikel Maron that renders points on a map from geocoded RSS (i.e. XML).

I feel almost a little embarassed to say it, but finding this tool is like a light coming on. Though I’ve spent several years working with web-based mapping applications, I had never truly ventured far from the realm of duplicating basic GIS functionality on the web. While this is no small task, it does fit into a fairly square box. While providing sophisticated geospatial information via a web interface is a challenging and notable pursuit, the beauty of geocoded RSS is both in it’s simplicity (recording point locations) and in the dynamism of its data source (RSS or Atom).

Simply put, this has all kinds of applications: from locating individual blog entries to logging photographic waypoints during a trip; from aggregating the geographic contexts of conversations that take place in ether-space to plotting time-series events in real time. Basically…lots of things…many more than I could possibly think of all at once.

Well, this is both humbling and exciting. And I have some research to do. And some tools to learn about. And hopefully before long I’ll have more to say on this topic.

UPDATES:

4.8.05
Just found Mappr, a site that displays locations of recently uploaded images on Flickr.

4.9.05
There’s also Flickr World Map that uses a site’s GeoUrl ICBM coordinates.

4.14.05
I’ve installed a version of Mikel Maron’s’s excellent worldKit package. The current installation shows global earthquake data from a USGS feed.

Being both a GIS head and a Mac aficionado, I’m very interested to hear of the release of GrassPro, which looks to be a complete desktop GIS for Macintosh and includes UMN Mapserver for web publishing. What a great looking application!

Of course, as I’m also an Open Source enthusiast, I’d probably just as soon opt to use Lorenzo Moretti’s GRASS for OSX implementation and install Mapserver independently. In this I see at least two advantages:

1. There is a small fee for GrassPro – though compared to the licensing fees for anything from ESRI, it’s nothing;
2. More importantly, compiling and installing Mapserver yourself ensures you have all the libraries you’ll need and none that you don’t .

Hopefully I’ll find an excuse to make use of these soon!

_{Thanks to The Map Room for the info and links.}

pAuthorize is a tool I sometimes use to implement a basic user/resource authentication functionality for websites where different users need access to different site resources. Using it will require a MySQL database and bit of tayloring.

The current release, version 0.3.4, is available under the GPL: pAuthorize.tgz

What follows is an excerpt from the README:

Out-of-the-box, pAuthorize applies a hierarchical value to each user and resource in order to determine a user’s authority to access the resource. A user’s authorization level must be equal-to or greater-than the authorization level of the resource in order to be granted access to the resource. For example, if user BOB has an auth-level 3, then BOB will be allowed to view all resources with auth-level 3 or lower. By default, there are four authorization levels defined at the time the database is created. This could be altered to suit any purpose by editing the file ‘tables.sql’. If desired, the hierarchical functionality of pAuthorize can be fairly easily changed, and a set of user-resource relationships established instead. By default, the SQL script creates a relate table (‘rel_user_resource’) that will handle these kinds of relationships.

I’ve already posted this on my personal blog, but I feel it fits more appropriately here:

Many content management software packages are configured to ping one or more syndication services upon submitting a new post. If you’re “rolling your own” blog or content management tool using php, the following code should do the trick:

<?php
require_once "XML/RPC.php";
$postURL = "http://www.myurl.com" ; // change to fit your blog host
$params = array( new XML_RPC_Value( $title, "string" ), new XML_RPC_Value( $postURL, "string" ));
$msg = new XML_RPC_Message("weblogUpdates.ping", $params);
$client = new XML_RPC_CLIENT( "/rpc/ping", "rpc.technorati.com", "80" ) ; // change for other ping hosts
$response = $client->send($msg);
$v = $response->value();
if (!$response->faultCode()) {
$rpcValue = $v->scalarval() ;
$rpcMessage = $rpcValue['message'] ;
$rpcMe = $rpcMessage->me ;
$rpcString = $rpcMe['string'] ;
print "<div>" ;
print $clientHosts[$i] ;
print " Response: <span> " . $rpcString . "</span>";
print "</div>" ;
} else {
print "<div>" ;
print $clientHosts[$i] . " Fault Code: <span> " . $response->faultCode() . "</span>";
print "<div>" ;
print "</div>" ;
print $clientHosts[$i] . " Fault Reason: <span> " . $response->faultString() . "</span>";
print "</div>" ;
}
?>

The following set of tools is carried over from my old website, “Paddy’s Wagon”. This collection of ARC/INFO AMLs (and a couple of ArcView Avenue scripts) may save some time doing batch processing of grids and coverages. The lot of them can be downloaded here: pbarabe_gis_toolbox.tgz.

ARC/INFO

• DOTarc – A “dot” arc file for configuring your A/I sessions
• ls.aml – Forced to work in NT-land? Too used to UNIX and/or don’t want to &sys dir all the time? Well then…
• cartoprism.aml – Makes a nice surface for display from coarse PRISM data
• clipem.aml – Clip multiple coverages in a directory or list of coverage names
• gridclipem.aml – Same as clipem.aml but uses the GRIDCLIP command in GRID module
• impcov.aml – Import multiple coverages from a list of e00 files
• jpgplot.aml – Use ARCPRESS to plot those jpegs you had to export from buggy ArcView (instead of just plotting your layouts)
• manyrename.aml – Rename multiple coverages or grids in a workspace based on string matching
• mergwkspc.aml – Merge two workspaces
• mvcov.aml – Copy a coverage to another workspace and kill the original
• mvgrid.aml – Same as mvcov.aml but moves a grid
• prjcov.aml – Project multiple coverages in a directory or list of coverage names
• quarterimg.aml – Split images from a list or directory into 4 quarters each.
• prjgrid.aml – Same as prjcov.aml but projects grids

ArcView

• l_quadzoom.ave – Zooms a View graphic in a layout to the extent of a user-chosen quad or region
• v_quadzoom.ave – Zooms a View to the extent of a user-chosen quad or region
• uniqueID.ave – Calculates consecutive, unique IDs into a field of the user’s choice