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

Paul Ramsey pramsey at cleverelephant.ca
Thu Dec 3 18:16:22 PST 2009


Thanks for sticking with it, and also reporting on your pain, Simon.
Knowing where your pain is will help us lower it for those in your
train.

P

On Thu, Dec 3, 2009 at 5:55 PM, Simon Cropper (Botanicus Australia Pty
Ltd) <scropper at botanicusaustralia.com.au> wrote:
> Peter,
>
> Sort of answered my own question. Found the EXE in the binary directory of
> PostgreSQL.
>
> Tried to get the program to work but I could not get the file to import the
> shapefile into a database. I will need to spend more time working on coming
> to grips with PostgreGIS, PostGIS and others components. This option is not
> a 'quick fix' rather 'a alternative way of thinking' -- resulting in a high
> learning curve as I have to master each individual component and the nuances
> of how the 2-3 utilities interact. Thanks anyway.
>
> 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
> web: www.botanicusaustralia.com.au
>
>
> Peter Batty wrote:
>
> Simon, you could do this as a PostGIS query. To take the polygon case, if
> you loaded the data into a table in PostGIS called parcel (say), you could
> run a query something like the following (not guaranteeing this is exactly
> correct but something along these lines):
> select a.id, b.id,
> ST_distance(a.geom, b.geom),
> ST_distance(ST_centroid(a.geom), ST_centroid(b.geom)),
> ST_azimuth(ST_centroid(a.geom), ST_centroid(b.geom))
> from parcel a, parcel b
>
> This would give you ids, shortest distance, distance between centroids and
> angle between centroids. There are no doubt others here who can correct my
> SQL syntax :) !
> There is a simple utility to load a shape file into PostGIS.
> Cheers,
>     Peter.
> On Thu, Dec 3, 2009 at 3:49 PM, Simon Cropper (Botanicus Australia Pty Ltd)
> <scropper at botanicusaustralia.com.au> 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...
>>
>> 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: scropper at botanicusaustralia.com.au
>> web: www.botanicusaustralia.com.au
>>
>> _______________________________________________
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>> Discuss at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/discuss
>>
>
>
>
> --
> Peter Batty - President, Spatial Networking
> W: +1 303 339 0957  M: +1 720 346 3954
> Blog: http://geothought.blogspot.com
>
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