[gdal-dev] compiling GDAL with GEOS on Windows

[Yilmaz Arslanoglu]

Hi Peter;

Thank you very much for the references. Actually I was considering too
to utilize
the Natural Neighbours concept, not only for nearest neighbour
identification, but also for
interpolating the values attributed to spatial points. I guess this
time a dynamic version of needs to be implemented,
since one needs to adapt the tesellation with the newly inserted query
point at eachnew query.
(assume that I have a set of points with their associated depth
values, and I use this set as
a source of querying new points with unknown depth)

Actually if it is not a problem for you, I would be pleased to see the
code to get a better
understanding about the algorithms involved.

Best regards,
Yilmaz

On Fri, Oct 2, 2009 at 8:24 AM, Peter J Halls <P.Halls at york.ac.uk> wrote:
> Yilmaz,
>
>   I'll leave the GEOS / Windows compilation bit to those who know!  However,
> I can help on the nearest neighbour issue as I have done some research in
> this area.  To do it properly is non-trivial: indeed, it is effectively a
> Dirichlet / Voronoi tessellation problem.  For an outline and some
> bibliography see
> Halls, P.J, Bulling, M., White, P.C.L., Garland, L., Harris, S., 2001,
> Dirichlet neighbours: revisiting Dirichlet tessellation for neighbourhood
> analysis, Computers, Environment and Urban Systems (CEUS) 25 pp105-117.
> This is based on Robin Sibson and Peter Green's 'Natural Neighbours'
> algorithm, Green, P., & Sibson, R, 1978, Computing Dirichlet tessellations
> in the plane; Computer Journal 21 pp168-173.
> This approach appears to be one of the fastest and most reliable algorithms
> for computing a Dirichlet Tessellation.  Once you have that tessellation,
> the neighbours of each point are easy to identify - indeed, they 'fall out'
> of the structure used by the Green and Sibson algorithm.
>
>   My software is written in Simula (the 'original' object programming
> language), using the CIM Open Source Simula cross-compiler from the
> University of Oslo and the OGR library via c calls.  My 'neighbours' program
> computes for each point in a dataset the set of 'natural neighbours' for
> each point, identifies that which is nearest and reports the distances and
> angles to each neighbour.  CIM is written in c and cross compiles into c.  I
> use the Cygwin interface on Windows and the gcc compilers: I cannot comment
> on building CIM in Visual Studio.  However, should you wish, I would be
> willing to supply you with my source.
>
> Best wishes,
>
> Peter
>
> Yilmaz Arslanoglu wrote:
>>
>> Hi;
>>
>> I am trying to build and install the GDAL library on Windows XP
>> using the following commands:
>>
>>   nmake /f makefile.vc
>>   nmake /f makefile.vc install
>>   nmake /f makefile.vc devinstall
>>
>> In order to build with GEOS support, I uncommented the lines
>> in the "nmake.opt" as follows:
>>
>> GEOS_DIR=C:\geos-3.1.1
>> GEOS_CFLAGS = -I$(GEOS_DIR)/capi -I$(GEOS_DIR)/source/headers -DHAVE_GEOS
>> GEOS_LIB     = $(GEOS_DIR)/source/geos_c_i.lib
>>
>> However, I still get the same .dll and .lib files as if no GEOS
>> support was turned on
>> (the sizes are exactly the same). When I try to call
>> "OGRGeometry::Contains()" method,
>> I also get the error:
>>
>> "ERROR 6: GEOS support not enabled."
>>
>> What could be wrong?
>>
>> 2) I was also wondering whether OGR library provides a kind of nearest
>> neighbour finding facilities?
>>   If not, does anybody know any library that could be integrated with
>> OGR for this purpose?
>>   I plan to use it to find the n nearest sounding points (SOUNDG)
>> given a point, to make a prediction
>>   about its depth.
>>
>> 3) Finally, is there any facility in OGR for querying a layer such that
>>    it will only return the features on it, which contain a given
>> point as parameter?
>>    Because I could not come up with an SQL statement to perform this task.
>>    Actually I was planning to use this on the DEPARE (depth area) layer on
>>    an S-57 file to find the depth area polygon that covers the given
>> point.
>>
>>     Any idea or references about these issues would greatly be
>> appreciated.
>>
>> Best regards,
>> Yilmaz
>> _______________________________________________
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>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>
> --
> --------------------------------------------------------------------------------
> Peter J Halls, GIS Advisor, University of York
> Telephone: 01904 433806     Fax: 01904 433740
> Snail mail: Computing Service, University of York, Heslington, York YO10 5DD
> This message has the status of a private and personal communication
> --------------------------------------------------------------------------------
>