Ditching GeoExt– building simple clients for MapFish

I’ve been enamored with the GeoExt interface for grabbing MapFish based print services since I first saw it. It’s a slick little interface, and can even been extended for multi-page print layouts pretty easily, ala http://tinyurl.com/mapfishmultipageprint. But as I’ve started to give thought not to what an organization full of professionals needs but what a public interface should looks (and probably those interfaces for professional … Continue reading Ditching GeoExt– building simple clients for MapFish

Leaflet, GeoServer, and Open Source Software Ramblings

I posted this post about an apparent problem in rendering of GeoJSON in Leaflet, and now it’s fixed a week later.  Why gush now, when for a few years developers on the GeoServer board have been fixing bugs I’ve found (often by the next day)?  Well for one, I very rarely find bugs in GeoServer– I just think I do, document everything, send it on, … Continue reading Leaflet, GeoServer, and Open Source Software Ramblings

Complex Symbolization in GeoServer or Compass Rose Mania– the GeoServer Version

At my place of employment, we have a vegetation survey program with enough potential plots to serve 50 years of data collection. The points are laid out in a Generalized Random Tessellation Stratified (GRTS) to maximize the statistical power of the analyses we do with them. Read more about GRTS. I dare you. Actually, it’s not so bad if you understand Quad-Trees and the like– … Continue reading Complex Symbolization in GeoServer or Compass Rose Mania– the GeoServer Version

What is the center line of a complex polygon? (cont. 3)

Just a quick post on this one, this time. I haven’t implemented an approximation of Bálint Miklós‘ Scale Axis Transform in PostGIS yet, and I don’t think I’ll dare try in GeoTools for GeoServer just yet, but I thought I’d give a preview of the sensitivity of the medial axis calculations in “bumpy” streams with the following image: As you can see, the problem isn’t … Continue reading What is the center line of a complex polygon? (cont. 3)

What is the center line of a complex polygon? (cont. 2)

I glossed over the difficulties of finding the centerline of a complex polygon in the last couple of posts, and didn’t realize the disservice until we got to the nitty-gritty of finding the centerline of “bumpy” streams, for which our solution, which is arguably a discretized version of the traditional medial axis, is quite sensitive to noise and “bumpiness”. With a little more googling, my … Continue reading What is the center line of a complex polygon? (cont. 2)

OGC Web Services and Security

I’ve been starting to inform myself on authentication/authorization schemes for OGC Web Services (OWS). This is because, while I’m pretty pleased with most of the functionality basic mapping of our internal GeoExt/GeoServer/PostGIS stack, user editing is the next natural step. As it is now, users can access a variety of really detailed useful layers, print to PDF, and for the most part the interface is … Continue reading OGC Web Services and Security

What is the center line of a complex polygon? (cont.)

If we try to extract the centerline of a polygon using Voronoi polygons, like in my previous post, it works pretty well for hydrologic cases, like extracting a stream centerline from stream banks, e.g.: We’ll use this to extract flow lines, in order to build out a better hydrologic network, but also use it to update property boundaries based on deed descriptions which may alternately … Continue reading What is the center line of a complex polygon? (cont.)

What is the center line of a complex polygon?

Sat in on a great presentation yesterday by Tim Schaub and Justin Deoliveira on GeoScript. Definitely check out their tutorials. To practice what I learned, I thought I’d apply it to the problem of how to find the centerline of a polygon. What do I mean by the centerline of a polygon? Well in the case of a stream that is drawn with both it’s … Continue reading What is the center line of a complex polygon?

PostgreSQL Views within GeoServer, GetFeatureInfo with Freemarker Templates, etc.

GeoServer now has the ability to consume database views from PostGIS, not just raw tables. I say it “now” has that ability– I think that came online with GeoServer 2.x series, but I’m just “now” starting to take advantage of it. You can also create views on the fly within GeoServer, but I prefer to apply the logic at the database level, just in case … Continue reading PostgreSQL Views within GeoServer, GetFeatureInfo with Freemarker Templates, etc.

Really loooong WMS requests

We have a GeoExt/Mapfish/GeoServer/PostGIS stack in house that allows us to print nice maps through a web interface. There has been a ceiling, however, as far as size– 140dpi and 22×34 has been the largest we’ve been able to render maps, and even then, sometimes the layers are too complicated. For a long time I was under the naïve impression that it was a memory … Continue reading Really loooong WMS requests