Category Archives: OSGeo

The SurveyOS Project’s SlitherGrid Toolkit

On January 19th, 2013 the California Chapter of the OSGeo is holding a hack-a-thon. I hope the geogeeks present will be interested in hacking on a new toolkit from the SurveyOS Project called SlitherGrid. Here is a description of the toolkit:

SlitherGrid is an open source toolkit for geospatial raster data processing written in the Python Programming Language. Its focus is on non-traditional raster data (LIDAR, elevation rasters, and other “non-optical” raster datasets). The toolkit is currently in a conceptual stage, although there is preliminary source code available on the SurveyOS Project SVN code repository.

Design Goals

The immediate design goals of the SlitherGrid Toolkit are:

  • Pure Python implementation with no dependencies on C programming language libraries.
  •  Ease of use.
  • Support for basic raster processing operations on 2D raster data grids.
  • Support for basic GIS and land surveying data formats.
  •  Pluggable software architecture that supports easy customization. This includes (1) the addition of support for additional raster and vector data formats, and (2) the addition of additional raster processing algorithms and tools.
  •  Built-in geospatial functionality. (The grids aren’t just simple arrays of numeric values. They support geospatial opertaions.)

The long term design goals of Slither Grid Toolkit are:

  • Support for multi-threading.
  • Support for 3D raster data grids.

Conceptual Toolkit Architecture Summary

The conceptual code of the toolkit is currently organized into four (4) Python modules. contains all of the classes for simple 2D raster data grids. (These are called “SlitherGrids”). contains utility geometry classes used to represent coordinates, angles, and simple vector geometry. contains classes that support basic file input/output, allowing the user to create 2D grids from common raster data formats. contains classes that can take a 2D raster grid and paint, or render it, to common image file formats for visualization.

The Sunburned Surveyor

Update on OSGeo Journal Volume 11

My work on OSGeo Journal Volume 11 continued today. I updated the California Chapter Annual Report Item to include new member activities from chapter members. I also completed the preliminary PDF versions of the Francophone Chapter and PDX Chapter Annual Report Items. Tomorrow I will work on the last chapter report that was submitted, for the one for the Korean Chapter.

I’m only waiting on one other Annual Report Item, from the Deegree Project.

My next step is to work on HTML versions of the report items so we can get this issue of the OSGeo Journal on the web as well as in PDF. I might also find time to convert the HTML files to EPUB.

The Sunburned Surveyor

Work on the OSGeo Journal Volume 9: 2011 Annual Report

I started work in earnest today on the OSGeo Journal Volume 11. This volume is the Annual Report for 2011. I realize I’m almost 7 months behind, but I hope to have next year’s annual report out by the end of March 2012.

Today I finished the preliminary PDF versions of the California Chapter Annual Report Item and the GRASS Software Project Annual Report Item. I’ll be working on the Korean Chapter, Francophone Chapter, and PDX Chapter annual report items next.

It sounds like we may get a topical article contributed this year. The article will be related to the Geopython Projects.

I’ll also be contributing three or four topical articles to this volume. The first will be an article on sharing GIS data models. It will discuss some of the work I’ve been doing to create a standard GIS model for Sanitary Sewer Networks as part of the CCVGPG Utility Working Group.

I’ll post more about this article and the other topical articles I’m contributing to Volume 11 later.

The Sunburned Surveyor

2012 OSGeo California Chapter Meeting Scheduled

The 2012 OSGeo California Chapter Meeting has been tentatively scheduled for Saturday, October 16, 2012. I’m looking for speakers and a place to host the meeting. Please let me know if you are interested in helping out with either.

I’ll try to get a web page up for the event soon. I’d like to coordinate the event with the release of some new training documentation/videos for OpenJUMP. We’ll see how that goes.

The Sunburned Surveyor

OSGeo Volume 9 Almost Here

I’ve haven’t had much time to blog the last two or three weeks. All my free time has been sunk into getting Volume 9 of the OSGeo Journal published. I hope to finally achieve that goal tomorrow. I’ve got one straggler report item to include, some page numbers to tweak, and then I’ll have the master PDF assembled.

I’ve learned quite a bit about Scribus during the process of preparing Volume 9. I wish some things were easier to do in Scribus, like page numbers and hyperlinks, but overall, I’m pleased with the final PDF I’ve produced using the program. I hope the readers are also pleased.

I’m already working to gather the material for Volume 11, the OSGeo Annual Report for 2011. My goal is to have that out by the end of March. That means I need to start work on a topical article for the volume. Volume 9 has two (2) topical articles I’ve written. One is on recent changes to the US patent system, and the other is an introduction to my JTS Warped software library.

I wanted to publish HTML and EPUB versions of Volume 9, but I’m not sure if I will have time. I need to try to integrate this into my workflow for Volume 11, so I can do the work as the PDF version is created. We will have to see how this goes. There is never enough time for everything I want to do.

The Sunburned Surveyor

Why the Free Version of SurveyMonkey Isn’t Really Useful

I recently put up a survey to collect information about what members of the California Chapter of the OSGeo might want from the upcoming annual meeting. This is the second or third time I’ve used SurveyMonkey. The web application makes it very easy to throw up a quick web form.

What I realized today is how limited the free version of SurveyMonkey is. You can’t download, export, or share any of your survey responses with the free version. That means you’ve got to copy them by hand from your screen if you want to do something useful with them. Yuck!

No more SurveyMonkey for me. (The basic plan is 17$ a month. I don’t use it enough to justify that cost.)

I’ll be using Google Docs forms or throwing up my own simple web forms from now on.

The Sunburned Surveyor