1. Canadian Geographer paper published

    Mon 12 October 2009
    cfarmer

    My article “Spatial-temporal patterns of snow cover in western Canada”, has now been published on-line with The Canadian Geographer. At this stage, only the proof copy is available online. The article is now officially published, and can be cited as:

    Farmer, C. J. Q., Nelson, T. A., Wulder, M.A. and Derksen, C. (2009). Spatial-temporal patterns of snow cover in western Canada, Canadian Geographer, 53 (4): 473-487.

    If you would like a copy, but do not have access to the article, please email me and I can forward you a PDF version.

    C

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  2. Remote Sensing of Environment paper published

    Tue 06 October 2009
    cfarmer

    My latest article, “Identification of snow cover regimes through spatial and temporal clustering of satellite microwave brightness temperatures”, has recently been published on-line, with the journalRemote Sensing of Environment. For now, UPDATE: The article can be cited as:

    Farmer, C. J. Q., Nelson, T. A., Wulder, M.A. and Derksen, C. (2010). Identification of snow cover regimes through spatial and temporal clustering of satellite microwave brightness temperatures, Remote Sensing of Environment, 114 (1): 199-210.

    If you would like a copy, but do not have access to the article, please email me and I can forward you a PDF version.

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  4. Voronoi polygons with R

    Wed 16 September 2009
    cfarmer

    To create a nice bounded Voronoi polygons tessellation of a point layer in R, we need two libraries: sp and deldir. The following function takes a SpatialPointsDataFrame as input, and returns a SpatialPolygonsDataFrame that represents the Voronoi tessellation of the input point layer.

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  6. Python, Matlab, and R

    Wed 12 August 2009
    cfarmer

    One project I’m working on at the moment involves exploring a dynamic extension of the Isomap algorithm for visualising constantly varying real-world road networks. Currently, we are testing out the method on a small scale simulated road network, and most of the original code (written by Laurens van der Maaten, with updates by Alexei Pozdnoukhov), was done in Matlab. Since this work is eventually going to have to run on relatively large datasets, and probably behind the scenes on a server somewhere, we decided that Python was the way to go. The goal therefore was to reproduce the Matlab code using only Python libraries, and the fewer additional libraries required, the better.

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  7. FOSS4G and teaching GIS

    Mon 20 July 2009
    cfarmer

    Two quicks notes to share:

    Firstly, please check out this excellent introduction to GIS by Tim Sutton, Otto Dassau, and Marcelle Sutton in partnership with the Chief Directorate for Spatial Planning & Information, Department of Land Affairs, Eastern Cape, South Africa, and the Spatial Information Management Unit, Office of the Premier, Eastern Cape, South Africa. They use QGIS to present some basic GIS concepts and skills, and I particularly like their section on Coordinate Reference Systems.

    Secondly, don’t forget to checkout the FOSS4G 2009 Free and open source software for geospatial conference in Sydney in October. There will be loads ...

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  8. ‘Watch’ long running processes

    Wed 08 July 2009
    cfarmer

    The other day I was loading a shapefile of approximately 11 million records into a PostGIS database (stay tuned for more on that later) and I wanted to know when shp2pgsql was done. Instead of continually checking the console, I decided to ‘watch’ the process using the *nix command watch. I discovered this handy tool a while ago, and have found that for long running processes, I can use watch to notify me when the process has finished, using the following command:

    watch -ben 1 "ps u -C shp2pgsql"

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