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

[Simon Cropper (Botanicus Australia Pty Ltd)]

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... POINTS -- UID_A, UID_B, DISTANCE, ANGLE LINES -- UID_A, UID_B, DISTANCE_AT_CLOSEST _POINT POLYGON --  UID_A, UID_B, MIN_DISTANCE, MAX_DISTANCE, HAUSDORFF_DISTANCE, CENTROID_DISTANCE, ANGLE_BETWEEN_CENTROIDS 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: scrop...@botanicusaustralia.com.au web: www.botanicusaustralia.com.au

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