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GeoServer, GeoWebCache

GeoServer and efficient delivery of raster data (image pyramid layer) (update)

A perennial favorite on this blog is “GeoServer and efficient delivery of raster data (image pyramid layer)“. I am neither the last nor the first authority on this topic (check the GeoSolutions blog for authoritative work on GeoServer and raster, also look to the GeoServer documentation), but I’ve had some good experiences with serving rasters in GeoServer, especially using image pyramid layers Read the original, … Continue reading GeoServer and efficient delivery of raster data (image pyramid layer) (update)

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FOSS4G-NA

G. I. O.: A Real American Hero (FOSS4G-NA)

Whew! What a conference! All the classic FOSS4G stuff was there, from why the breaks in version for PostGIS (serialization + more…) = 2.0 rather than 1.6, to “here are the new combinations of existing technology stacks”, to the “tribes” of Open Source GIS. I will confess: when I went to FOSS4G 2011 in Denver, I was a little terrified to actually meet and interact … Continue reading G. I. O.: A Real American Hero (FOSS4G-NA)

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Security

Arming an escaped convict– giving Artillery to a Jailbroken iPod Touch

Some achievements are too easy, but that shouldn’t be construed as complaint. This one was pure fun. Keeping in mind dire warnings of the dangers of rooting my iPod from security professionals I know and respect, I decided to root a spare iPod, so I wouldn’t have to worry so much about security for my primary one with all its precious info. Once rooted, how … Continue reading Arming an escaped convict– giving Artillery to a Jailbroken iPod Touch

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Analysis, Cartography, Database, PostGIS, PostgreSQL, SQL, Trail Curation, Trails

PostGIS Cartographic Effects– Cartoonify Nearly Coincident Lines

I’m still working on this query, but I thought I’d post what I’ve done so far. My intent is to produce scale-dependent exaggeration of the distances between quasi-parallel lines. The reason for this is so that lines such as street lines which are nearly coincident at a particular viewing scale can be spread from each other, much in the same way great cartography lies a … Continue reading PostGIS Cartographic Effects– Cartoonify Nearly Coincident Lines

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Database, PostGIS, PostgreSQL

PostgreSQL dump for PostGIS upgrade

I’m working through the Hard Upgrade instructions for PostGIS 2.0SVN install instructions. No great surprises, but a succinct set of steps for trying out PostGIS 2.0 early. In our case, we needed to exclude larger (30GB) tables from the dump needed to do an upgrade– we’ll build those into the new database selectively. Looking to the pg_dump instructions, the dash “T” (-T) flag is what … Continue reading PostgreSQL dump for PostGIS upgrade

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Analysis, GeoServer, PostGIS

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)

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Analysis, Database, Ecology, PostGIS, Security, SQL

Postgis for breakfast: ST_Donut

This post typed into my iPod as an homage. Assisted today by my collegue, J. Stein. Moderate obfuscation of locations is an important technique for the protection of data, say something sensitive like the nesting locations of the very rare and strange fuzzy-bellied gnat catcher. We still want to display the data, but want to make it slightly wrong. A naive approach would place it … Continue reading Postgis for breakfast: ST_Donut

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Recreation, Trail Curation, Trails

Looping Trails– alternate routing for recreational use (cont.)

I’ve been thinking more about the recreational looping problem, given a start location and a given range of travel (e.g. 0-3 miles). A way to approach this is to build up loops from a set of nodes to which has been applied a traveling salesman algorithm. To test this on a piece of paper, before digging under the hood of e.g. pgRouting or OpenTripPlanner, I … Continue reading Looping Trails– alternate routing for recreational use (cont.)

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GeoServer

GeoServer Optimization

As we move away from a simple stack of PostGIS/GeoServer/GeoWebCache/Openlayers to wrapping a MapFish print service into the stack, it’s time to think more seriously about optimizing and stabilizing GeoServer. In preparation for this step, I’ve been setting up a series of VMWare ESX-hosted Debian Linux VMs to function as the cluster of geospatial services. Fortunately for me, there’s plenty of great advice in Andre … Continue reading GeoServer Optimization

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