[OSGeo-Discuss] Quick hello and request for assistance finding Open Source

Stephen Woodbridge woodbri at swoodbridge.com
Thu Dec 3 15:25:47 PST 2009


You might want to look at PostGIS. It is a GIS extension to the 
posgresql database. There are windows installers for it. There is a 
shapefile loaded and dumper, so you can easily load a shapefiles into 
tables then do SQL queries with geospatial function. The postgis support 
list has a bunch of very sharp people that can help you get started 
doing the queries that you need to generate you results.

-Steve W

Simon Cropper (Botanicus Australia Pty Ltd) wrote:
> Hi Everyone,
> My name is Simon and I am an environmental consultant. I use a variety 
> of open source GIS systems and tools almost every day to analyse flora, 
> fauna and vegetation data. I am interested in OSGeo both from the 
> standpoint (or my underlying belief) that software and data should be 
> free (you know how the mantra goes) and my desire to contribute to a 
> broader community effort to develop appropriate software for users. I 
> have been actively using OpenJUMP, Kosmo, OpenEV, EveryDWG and Sextante. 
> I have tinkered with Ilwis, GRASS, Quantum (various versions) and a few 
> others I have lost track of. I am currently using GVSIG+Sextante, which 
> I find very useful and easy to use. I am an old user of ArcView 
> 3.1+(numerous scripts/extensions).
> I have a common GIS problem but can not find any OSGeo project that has 
> provided a set of tools to combat it. I need to establish the 
> distance+angle between various geometries (points, lines, polygons) in 
> same layer and in different layers. A specific problem I currently have 
> is finding the minimum distance and angle between 200 odd polygons in 
> the same layer. Each polygon has a unique id and I want to get a table 
> with UID_A, UID_B, MINIMUM_DISTANCE, ANGLE. I know that ArcGIS and 
> ArcView have this functionality, and script exist for old versions of 
> ArcView, but I am looking for an Open Source alternative.
> Ideally such a tool would create the following data for each geometry 
> type...
> What I have found already...
>     * I have noted that Sextante can create a matrix of distances
>       between points within the same layer. With rows and column
>       representing the complete set of points being compared.
>     * I have also found QGIS has a fTools Plugin that allows you to
>       "Measure distances between two point layers, and output results as
>       a) Square distance matrix, b) Linear distance matrix, or c)
>       Summary of distances." QGIS 2009.
>     * I suspect that GRASS would provide this functionality but can't
>       get that package to work on my system (even WinGRASS), so if you
>       point me here please also point me to a tutorial on getting the
>       thing to work (this system is not intuitive; My problem has been
>       in establishing a repository and getting data into it for viewing,
>       let alone analysis; it failed the age old test that if you can't
>       even get the thing running in half an hour, the learning curve is
>       going to be way too high to use in in normal business activities;
>       I have tried - yes following their instructions - several times,
>       and spent several days reading manuals, wiki's,etc to no avail).
> BUT I can't find any tool that allows me to calculate the minimum 
> distance between polygons and indicate the direction of the polygon.
> Anyone out there know of such a tool?
> Note: I am using Windows XP Pro SP3 and store all my GIS data as shapefiles.
> -- 
> Cheers Simon
> Simon Cropper
> Botanicus Australia Pty Ltd
> PO Box 160, Sunshine, Victoria 3020.
> P: 9311 5822. M: 041 830 3437.
> mailto: scropper at botanicusaustralia.com.au 
> <mailto:scropper at botanicusaustralia.com.au>
> web: www.botanicusaustralia.com.au <http://www.botanicusaustralia.com.au>
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