Hello list, My original question was if anyone had opions on the use of
using classes of a continuous variable, not thresholds for indicator
kriging.

Respones are as follows:
Pierre Goovaerts, as helpful as ever, suggested:

Benamghar and Sonnet. 1999. Performance comparison of cumulative and class
indicators approaches for pollution risk assessment. In
J.~G\'omez-Hern\'andez, A.~Soares, and R.~Froidevaux, editors, geoENV II -
Geostatistics for Environmental Applications, pages 357-368. Kluwer Academic
Publishers, Dordrecht.

Wingle, W.L., and E.P. Poeter, 1998, Classes vs. Thresholds: A Modification
to Traditional Indicator Simulation, Advances in Geostatistics, 1998 AAPG
Annual Meeting, Salt Lake City, Utah, May 17-20, 1998, which is available at
http://www.mines.edu/fs_home/wwingle/pubs/aapg_98/class.html.

The only potential drawback with class indicators is that the experimental
semivariograms will tend to be more erratic than for cumulative indicators
because they will be based on a smaller proportions of non-zero data. For
example, if you use decile thresholds to define 10 classes, each class
indicator variable will consist of 10% of 1 and 90% of 0, while for
cumulative indicators this ratio will be observed only for the first and
last threshold. It's the reason why the semivariogram for a median threshold
(50% of 1 and 50% of 0) is usually one of the best behaved.



Simon Kelly suggested:

Our software (Gemcom mining and geological software - www.gemcomsoftware.com
) performs MIK (Multiple Indicator Kriging) in the fashion you describe and
gives an estimate and associated probability for each grade bin for each
cell. However, the overall grade is not given by the grade with the highest
probability. The overall grade is the sum of the mean (median in the top
bin?) of the bin multiplied by the probability of achieving that grade.
Another way to see the indicator probabilities is as proportions of
different grade bins in each block. I hope I've understood you and that you
understand me.

Bob Sandefur suggested:

Traditional IK (indicator kriging) will give delta classes if you subtract
the kriged indicators one from another ie prob(x>=0.1 and
x<0.2)=prob(x>=0.1)-prob(x>=0.2)

I think (but don't know) that the experimental variograms of your suggested
intervals will be harder to interpret that i traditional IK variograms (I
suspect they will look like white noise variograms (ie flat)). Like in IK
where they check order relations you will have to check that the sum of your
indicators=1 (they won't exactly unless all your classes have same
variogram.

I never heard of it until now but its worth a try (I would assume the early
IK people tried this and found it was harder that traditional IK) but in
mining where IK started we're usually interest in totals above a cutoff not
amount between cutoffs.

Thank you all very much.  A very useful webpage about indicator kriging and
UNCERT software is :  http://uncert.mines.edu/sisim/sisim.html .

Regards,
Andy

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Dear group,

I am currently struggling with an interpolation problem dealing with
obstacles and I would like to get advise from more experienced persons.

Data : 8 000 answers to a survey corresponding to roughly to 4000 postal
code centroids.

Goal : interpolate these answers over the Island of Montreal (500 sq.
km) in order to produce a grid allowing further analysis.

Problem : interpolate the answers only in specific land-use polygons,
taking into account holes and not compatible land-use polygons for the
distance calculations.

I have to use VM but it does'nt seem to take into account such obstacles
in its calculations. All it seems to be able to do is mask the results
with the undesirable polygones. Someone told me about gstats, but can it
solve this problem ?

A truck load of thanks,

patrick


--
Patrick Maupin

Ecole Nationale Superieure des Telecommunications de Bretagne
Departement Image et Traitement de l'Information
29285 BREST CEDEX FRANCE

Ecole de technologie superieure
Departement de genie de la production automatisee
1100, rue Notre-Dame Ouest
Montreal (Quebec), Canada H3C 1K3
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Call for Abstracts and for Proposals of Special Sessions

--------------------------------------------------------------------------------\
------------
The 16th Annual Symposium of the US Regional Chapter of the International
                         Association of Landscape Ecology (US-IALE)

      Memorial Union, Arizona State University, Tempe, AZ, April 25-29, 2001
--------------------------------------------------------------------------------\
------------
                                 CALL FOR ABSTRACTS

A major goal of landscape ecology is to understand the interactions between
spatial pattern and ecological processes, the role of scale, and
hierarchical linkages in heterogeneous landscapes that are increasingly
shaped by human activities. This understanding is essential not only for
unraveling how nature works, but also for developing a harmonious
relationship between humanity and nature. The theme of the 2001 US-IALE
Symposium will be understanding the interactions among pattern, process,
scale, and hierarchy in human-dominated and natural landscapes, with a
special emphasis on landscapes that have been profoundly modified by humans.
We welcome oral and poster presentations that are relevant to the symposium
theme.

Abstracts should be sent to the Program Chair: Dr. Jianguo (Jingle) Wu,
Department of Life Sciences, P.O. Box 37100, Arizona State University -
West, Phoenix, AZ 85069 (Email: jingle@..., Phone: 602-543-6131, Fax:
602-543-6131). Note that only electronic submission is acceptable. The
deadline for the submission of abstracts is November 30, 2000. Abstract
submissions must follow the specific instructions below.


                INSTRUCTIONS FOR ABSTRACT PREPARATION AND SUBMISSION

      * Only one presentation (oral or poster) will be allowed for each person
         as the senior author, although one person may be a co-author on
         multiple presentations.

      * Acceptance notice will be sent to submitting authors electronically by
         January 1, 2001, and the presentation schedule will follow as soon as
         it becomes available.

       * It is assumed that the submission of an abstract indicates that the
         author allows its publication in the US-IALE 2001 Program and on the
         US-IALE 2001 web site.

       * Regular slide and overhead projectors will be available for all oral
         presentations. A computer projector with standard PC connections will
         be provided when necessary. But the presenter must have his/her own
         laptop computer and it is up to the presenter to make sure of the
         connection compatibility between the computer and the projector. We
         highly recommend a backup form of the presentation (slides or
         overheads) be available.

       * For poster, boards will be 6 feet in length and 4 feet in height.

         ------------------------------------------------------------------------
         Two Ways of Submitting Your Abstracts
         ------------------------------------------------------------------------

Option 1 - Online Abstract Submission. Go to the web site of US-IALE 2001 at
http://www.west.asu.edu/LEML/iale2001, and follow the on-line instructions
for abstract submission.

Option 2 - E-mail submission. If you choose this option, please follow
instructions below carefully, without omitting any requested information:

      * Please send your abstract to both of the following two email addresses:
         jingle@... AND iale2001@.... You should get a
         confirmation message after your abstract has been received.

      * Use TEXT format directly in email message (No attachments or word
         processing files).

      * All abstracts must be in English with a maximum of 250 words (not
         including the title and information on authors).

      * The abstract should start with author's name, affiliation, and
         presentation title. After a blank line the body of the abstract
         follows. Note that, after the main body of the abstract, additional
         information on the presentation is required (see the example provided
         below).

      * For abstracts with multiple authors, place an asterisk next to the
        presenter's name.

      * Put all authors in order, and then the order of their respective
        affiliations (number them if different). For the first (or sole)
        author, put the last name first, followed by the first name and middle
        initial. For co-authors, the last name should follow the first name and
        middle initial (see the example below).

      * Remember to provide the following information at the end of your
        abstract: (1) contact information on the corresponding author; (2)
        whether you prefer an Oral or Poster presentation and if you are
        willing to make a poster presentation if your oral presentation cannot
        be scheduled; (3) whether the abstract is a student presentation that
        enters the competition for the Best Student Presentation Award (more
        information on awards and procedures on judging are provided in the
        IALE Newsletter and on the US-IALE2001 web site), and (4) whether you
        need special AV equipment other than slide and/or overhead projectors
        (specify).

       * If the abstract contains any special characters, use the following
         conventions:

                 Special Text                  Symbol to Use          Example

                Italics (Stipa grandis)        <i>   </i>  <i>Stipa grandis</i>


               Superscript (m2)             <sup> </sup>       m<sup>2</sup>

               Subscript (NH4)               <sub> </sub>       NH<sub>4</sub>

                Greek letter  (=B5)             (spell out)                MU

--------------------------------------------------------------------------------\
------
ABSTRACT EXAMPLE:

From: hlandskap@...
Subject: us-iale2001 abstract
To: jingle@..., iale2001@...

Wu, Jianguo1, Laura Musacchio2, and Heterogy S. Landskap3,*. 1Department of
Life Sciences, Arizona State University-West, Phoenix, AZ 85069, USA;
2School of Planning and Landscape Architecture, Arizona State University,
Tempe, AZ 85287, USA; and 3Department of Landscape Ecology, University of
Mars, Phoenix, AZ 80000, USA. Pattern and Process in Landscapes from Arizona
and Mars: Generality and Idiosyncrasy.

Understanding how spatial heterogeneity and biotic and abiotic processes
interact is essential in the study of the functioning and dynamics of
complex landscapes. By taking a comparative approach, we have investigated
the pattern and process interactions in several landscapes from the central
Arizona and Mars, respectively. =3D8A=3D8A


Author to contact: Heterogy S. Landskap
Mailing address: Department of Landscape Ecology, University of Mars, PO Box
30000, Phoenix, AZ 80000, USA
Phone number: 666-666-6666
=46ax number: 666-666-6667
E-mail: jingle@...
Preferred form of presentation (oral or poster): Oral
Poster as alternative if necessary: Yes
Best student presentation competition: No
Special AV: PowerPoint presentation (PC)

--------------------------------------------------------------------------------\
-------
--------------------------------------------------------------------------------\
-------

                         CALL FOR SPECIAL SESSION PROPOSALS

The theme of the 2001 US-IALE Symposium will be understanding the
interactions among pattern, process, scale, and hierarchy in human-dominated
and natural landscapes. If you are interested in organizing a special
session on a topic that is relevant to the theme, please submit a proposal,
preferably by email, to the Program Chair:

                              Dr. Jianguo (Jingle) Wu
                            Department of Life Sciences
                  P.O. Box 37100, Arizona State University - West
                                 Phoenix, AZ 85069
                               Email: jingle@...
                        Phone: 602-543-6131 Fax: 602-543-6131

The deadline for the submission of proposals is October 25, 2000. The
decision of acceptance of proposals will be made by November 15, 2000. All
special session proposals must follow the instructions below. After the
proposed special session is accepted, the abstract of each presentation must
be sent to the program chair by November 30, 2000 in the required format
(see Calls for Abstracts and information on the 2001 US-IALE Symposium web
site: http://www.west.asu.edu/LEML/iale2001).

--------------------------------------------------------------------------------\
-------
Instructions for Special Session Proposals

          All proposals for special sessions must contain the following
         information in the order indicated below:

              1. Organizer:
               * Name, affiliation, mailing address, phone, fax, email address

              2. Title of the special session:
                 * Full title of the proposed special session

              3. Proposal Summary:
                 * Describe the significance of the special session and its
                   relevance to the theme of the 16th US-IALE symposium

              4. List of potential speakers:
                 * List all potential speakers you have contacted or will
                   contact, with the tentative titles of their talks and their
                   affiliations
                 * Proposed time duration for each presentation

              5. Possible outcome of the special session:
               * Is any form of publication being planned based on the special
                 session? What other forms of outcome from the special session
                   do you expect?
--------------------------------------------------------------------------------\
-------
--------------------------------------------------------------------------------\
-------
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Dear list,

We are pleased to announce the 4th Conference of the Working
Group on Pedometrics of the International Union of Soil Sciences
to be held in Gent, Belgium, on September 19-21, 2001.

Aim and scope of the conference :
The central theme of this conference is “Applications of
Pedometrics”. Therefore the conference aims to focuson
applications of numerical and statistical methods in soil-related
research. Fields of application typically include : survey and
mapping, evaluation and planning, environmental assessment,
precision agriculture, sampling strategy and design, modelling of
dynamic processes, error management and decision support, …

Scientific committee :
Pierre Goovaerts, University of Michigan, USA
Gerard Heuvelink, University of Amsterdam, The Netherlands
Murray Lark, Silsoe Research Institute, UK
Alex McBratney, University of Sidney, Australia
Alfred Stein, University of Wageningen, The Netherlands
Richard Webster, Rothamsted Experimental Station, UK

More info and a pre-registration form can be found on the web
page :
http://soilman.rug.ac/pedometrics2001

Best regards,

Marc Van Meirvenne
Chairman WG-PM
Dept. Soil Management and Soil Care
Fac. of Agricultural and Applied Biological Sciences
Ghent University
Coupure 653, 9000 Gent, Belgium
Tel. + 32 (0)9 264 6056
Fax  + 32 (0)9 264 6247
e-mail : Marc.Vanmeirvenne@...
http://soilman.rug.ac.be/~mvm


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Dear list,

The correct homepage of the Pedometrics 2001 conference is :
http://soilman.rug.ac.be/pedometrics2001.

Sorry for the confusion.

Marc Van Meirvenne
Dept. Soil Management and Soil Care
Fac. of Agricultural and Applied Biological Sciences
Ghent University
Coupure 653, 9000 Gent, Belgium
Tel. + 32 (0)9 264 6056
Fax  + 32 (0)9 264 6247
e-mail : Marc.Vanmeirvenne@...
http://soilman.rug.ac.be/~mvm


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hello,

I am from Indonesia.
I am very interested to the GIS and know I start to learn by my self about
it by ArcView.
I need some real practise to improve my self, and I will happy to joint for
some real project but i will do by net. ( I will do in my country).
I dont intent to the fee ..... I will do even for free.
If somebody have a real project which possible for me to joint .. I will
happy to joint the team for free.
Please contact me.

Hary Kartiko
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Dear list,

Apparently on-line pre-registrations to the Pedometrics 2001
conference might not reach us in some specific circumstances. If
you have mailed the pre-registartion form on-line from the
conference web page and you have not received a confirmation,
please contact the secretary by e-mail at :
marijke@....

Best regards,

Marc Van Meirvenne
Dept. Soil Management and Soil Care
Fac. of Agricultural and Applied Biological Sciences
Ghent University
Coupure 653, 9000 Gent, Belgium
Tel. + 32 (0)9 264 6056
Fax  + 32 (0)9 264 6247
e-mail : Marc.Vanmeirvenne@...
http://soilman.rug.ac.be/~mvm

Interested in Pedometrics ?
Visit : http://soilman.rug.ac.be/pedometrics2001


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Apologies for cross-posting


Hello,

My name is Nat Evans, and I am at present at the initial stages of carrying
out research for the 'Geo-Crosswalk Project', a project, which I hope, will
be of interest to you. Before I get to the crux of this e-mail I should
provide a brief outline of what the project aims to achieve...

The 'Geo-Crosswalk Project' is a collaborative project (between EDINA, the
History Data Service and the Data Archive, with MIMAS and the Archaeology
Data Service) investigating the feasibility of developing and providing an
online, Z39.50 compliant, British and Irish gazetteer service, which would
play a crucial role supporting geographic searching within the UK Higher
Education community (and associated services).

A gazetteer service would assist metadata creators by providing a means of
converting geographic names to a standard spatial coding scheme. It would
parse metadata records to identify geographic names (current and historical)
and convert them into geographic 'footprints' (i.e. co-ordinates
representing the location of a named place) expressed in a standard spatial
coding scheme such as latitude and longitude or the Ordnance Survey National
Grid. A gazetteer service would also make it possible for information
retrieval systems to support a full range of geographic search options. It
would provide a mechanism by which information retrieval systems could
translate the spatial element of any query into the native spatial coding
scheme.

There will be a vast range of questions that can be asked of the gazetteer,
with the only limit being what data is accessible and how it will be
accessed. Following are some examples of the type of questions this service
would be able to provide answers to:

* Where were locksmith shops located in late 19th century Cardiff?
* Within which county is Colchester?
* What are the national grid co-ordinates for the Roman town of Isca
Dumnoniorum ?
* By what alternative names is Sgurr na Ciche in Knoydart known?
* Which rivers run through Northumberland National Park?
* Here is a list of current parishes in Western Scotland, tell me the
equivalent Civil Parishes in 1850.
* What police force areas cover SW England?
* Through which counties does the M1 pass?
* Here is a piece of text. Find any place names mentioned in the text.
* What were the crime rates in the Easterhouse estate during the
1960's?
* Which ferries go to the Ardnamurchan peninsula?
* What was Cirencester known as during the Roman period, and what was
its extent?
* What is the distribution of school exclusion rates within the postal
districts of Tyne and Wear?

My role within this project is to undertake a preliminary investigation to
fully identify the nature, extent and needs of the user community and then
to identify suitable data sources for populating a British and Irish
gazetteer. Primarily this has been defined as organisations that hold
georeferenced data sets (i.e. datasets with a geo-spatial reference such as
an Ordnance Survey National Grid reference, a postal address, a place name,
et cetera). This encompasses a very broad spectrum of available data, as it
has been estimated that as much as 80% of data collected in Britain today is
georeferenced!

I would therefore be interested to hear from anyone who feels that they may
be a potential constituent of the user community in terms of how they
envisage using this sort of gazetteer service and what sort of functionality
they would expect it to have (e.g. data storage issues, usability,
performance, security, et cetera). I would also be interested to hear from
potential end-users in terms of the functionality they would expect from
such a gazetteer service. Finally any suggestions as to suitable data
sources for populating the gazetteer would be gratefully received.

Please could you reply off-list, unless of course you wish to begin a thread
discussing the uses of gazetteers. I look forward to receiving your replies
and hearing your comments.

Thanks,

Nat Evans


*******************************************************************
Geographic Information Officer (Geo-Crosswalk Project)
The Data Archive
University of Essex
Colchester
CO4 3SQ
United Kingdom

Tel: +44 (0) 1206 873934
e-mail: nevans@...

http://www.data-archive.ac.uk/
http://hds.essex.ac.uk/
*******************************************************************

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This letter informs you of the forestery reference in Rev Ciencia Forestal en México 19 (76) 1994: 141-152 by Bertil Matérn of the Dept of Forest Biometry, University of Agricultural Sciences, Umea, Sweden. The Poisson forest (Keuls et al., 1963), the angle count method (Bitterlich, 1984) and the central satellite model (Warren, 1991) are emphasized. Basal area at breast height going to square meters per hectare is the main target.

Using Goodland’s (1971, J Ecol) work on the Brazilian Cerrado quite apart from Matérn’s brilliant review, the writer calculated these relations for 4 niches—1) grassland, 2) matorral (short open woods), 3) light forest & 4) forest. The relation of the 4 sites (X) to basal area (Y) is logistic, site by number of tree species fits: Species = a + b(Site)3  + c exp-Site, and Site by tree height fits: Height = a + b(Site) + c(Site)2. The coefficients of determination are at unity, and these relations are ideal. As the X and Y axes have only 4 points, perfect curves must result. These relations may help in the statistical management of new data from different niches.

When the foliar morphometric averages in 4 mezquitales (mesquite woods) are so compared, logistic equations explain site by leaflet length and site by rachis length, because the curve that runs through any 4 points is likely to be logistic, sine, exponential, extreme value, rational, etc.  Also, using (or overusing!) averages is just not the same as running a fit through the many original data points. Bias must arrive, because the experiential judgement of the researcher is called upon for expression of reasonable caution in the use of such models since many work as well as another. When several thousand raw data points are run, the results could be DF Adj r2 = 0.25 or less, leaving one to wonder what happened.

More, of course. See Means, JE et al, “Software for computing plant biomass—BIOPAK user’s guide,” USDA, Forest Serv, Gen Tech Rep PNW-GTR-340, which refers to a DOS program on Internet that has a library of equations. Go to http://www.fsl.orst.edu/lter/data/software/biopak.htm

Best Regards, Paul R. Earl

PS See Software at http://www.fs.fed.us/links/software.shtml

Dear Statistician,

This letter informs you of the forestery reference in Rev Ciencia
Forestal
en México 19 (76) 1994: 141-152 by Bertil Matérn of the Dept of Forest
Biometry, University of Agricultural Sciences, Umea, Sweden. The Poisson

forest (Keuls et al., 1963), the angle count method (Bitterlich, 1984)
and
the central satellite model (Warren, 1991) are emphasized. Basal area at

breast height going to square meters per hectare is the main target.

Using Goodland’s (1971, J Ecol) work on the Brazilian Cerrado quite
apart
from Matérn’s brilliant review, the writer calculated these relations
for
4 niches—1) grassland, 2) matorral (short open woods), 3) light forest &

4) forest. The relation of the 4 sites (X) to basal area (Y) is
logistic,
site by number of tree species fits: Species = a + b(Site)3  + c
exp-Site,
and Site by tree height fits: Height = a + b(Site) + c(Site)2. The
coefficients of determination are at unity, and these relations are
ideal.
As the X and Y axes have only 4 points, perfect curves must result.
These
relations may help in the statistical management of new data from
different niches.

When the foliar morphometric averages in 4 mezquitales (mesquite woods)
are so compared, logistic equations explain site by leaflet length and
site by rachis length, because the curve that runs through any 4 points
is
likely to be logistic, sine, exponential, extreme value, rational, etc.
Also, using (or overusing!) averages is just not the same as running a
fit
through the many original data points. Bias must arrive, because the
experiential judgement of the researcher is called upon for expression
of
reasonable caution in the use of such models since many work as well as
another. When several thousand raw data points are run, the results
could
be DF Adj r2 = 0.25 or less, leaving one to wonder what happened.

More, of course. See Means, JE et al, “Software for computing plant
biomass—BIOPAK user’s guide,” USDA, Forest Serv, Gen Tech Rep
PNW-GTR-340,
which refers to a DOS program on Internet that has a library of
equations.
Go to http://www.fsl.orst.edu/lter/data/software/biopak.htm

Best Regards, Paul R. Earl

PS See Software at http://www.fs.fed.us/links/software.shtml

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Hello All:

check out the updated reports http://www.bcforestry.com

they are on the bottom of the front page

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Just to remind everybody that Practical Geostatistics
2000 by Isobel Clark and Bill Harper has finally hit
the streets - well, the Web anyway. You can even get
it on Amazon.com!

The hardcopy book is 442 pages and the "old" Practical
Geostatistics starts half way through Chapter 8!

The book is also available as hypertext on CD. It is
pretty flat at the moment, with only major hypertext
links, but we hope to make it a lot more flexible in
later editions.

The CD also includes a demo copy of the Geostokos
software and 13 data sets for teaching, learning and
generally playing around with.

The software and data sets are also freely available
to anyone -- even cheapskates who won't buy the book.

Check this out at
http://uk.geocities.com/drisobelclark/PG2000_demo.html

There is also information on the Contents of the book
and a rough copy of Chapter 1 on the same site.

The old book is also available as download in a bad
photocopy version or in Latex. The latter is readable
(and printable) using the free Scientific Notebook
Viewer which you can download from
http://www.mackichan.com/products/dwnld-inst.html
[Note: you have to go way down the page to find the
free version!!]

Details on downloading Practical Geostatistics 1979
(yes really, I am only that old) at:
http://uk.geocities.com/drisobelclark/practica.html

I have put all this stuff in folders in my Yahoo
briefcase. If you want to be really rude you can go
straight there:
http://uk.briefcase.yahoo.com/drisobelclark

I would prefer you to at least visit my own pages and
SIGN THE GUESTBOOK!!!!!!!!

Everything in the briefcase is free and freely
distributable. I know we aren't supposed to solicit
data sets, but if you have any you are willing to
share with the geostatistical world, we are willing to
host them in the briefcase and modify for use with the
PG2000 demo software.

Visit http://geoecosse.hypermart.net for Web
purchasing of the book, CD and the 'real' software
(EcoSSe). For direct purchasing contact me for Africa,
Australasia and the Far East and e_cosse@...
for Europe, CIS and the Middle East.

We are currently finishing a separate volume of
"Answers to Exercises". Bona fide teachers can obtain
a free "notes for educators" when buying the second
volume. Now taking suggestions for Volume Two
scheduled for early 2001. So far have simulation,
discrete processes, co-kriging and anecdotes. All
conributions gratefully accepted!

Contact me personally at drisobelclark@...

Enjoy!
Isobel Clark



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Suppose I have a variable (Leaf area index) that shows periodicity in its
semivariograms (at several lags). And this periodicity can be seen in the
E-W direction in a satellite image. There is also a N-S trend (values
increasing to the south). When modeling an omnidirectional variogram, a
nested model including a spherical and hole effect structures fits
adequately the sample variogram. The rose variogram indicates that the
azimuth angle = 160 degrees is the major direction of continuity; so 160 and
70 degrees are the angles selected to approach the problem with anisotropy.
The directional variograms also show periodicity but the hole model effect
cannot be applied in more than one direction (Deutsh and Journel,
Geostatistical Software Library and user's guide, page 25). So each
directional variogram is modeled with a nested model including two spherical
models; this model does not represent the periodicity of the variable. When
performing ordinary kriging or conditional simulation the use of the
omnidirectional model gives better results (visually and statistically)than
the use of the anisotropic model.

Is there a way by which I can include the periodicity in the anisotropic
model or do I just have to accept the omnidirectional approach as the best
one in this case, because it represents better the periodic behavior?

Thanks in advance,
mercedes berterretche
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Hi Mercedes

You have what we call the "Paddington Mix" model -- a
mixture of spherical components with a 'ripple' effect
around it. I have used anisotropic Paddington Mixes
very successfully in several different geological
different applications.

The reason we call it the Paddington Mix is that it
was first included in the Geostokos software for an
application at Paddington Mine in Western Australia.
This is a shear-enhanced gold mineralisation, where
the gold values are not restricted to shear zones
(cyclic) but are richer close to the shears. So we had
a model with a basic two component spherical but with
a cyclic component which varied wildly according to
whether it was parallel to or perpendicular to the
shears. To get the anisotropy, we varied cycle length
and damping parameter to achieve almost pure spherical
'along shears' and strong cycles across shears.

The model has also been used to characterise potholes
or ballrooms in platinum reef mineralisation, and we
(me and Gavin Lind) have a paper to be presented in
South Africa next month on using indicators and the
paddington mix to track down pillars and voids in old
abandoned coal mines.

You can see examples of the Paddington Mix in
Practical Geostatistics 2000, although we don't have
any anisotropic models in the book. Got to leave
something for Volume 2!

Check it out at http://geoecosse.bizland.com and the
book software at
http://uk.geocities.com/drisobelclark/PG2000_demo.html.

Isobel Clark

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Hi-

  Suppose I have some spatial samples with weights (w1 w2 ....)  and I want to
use these weights in addition to  kriging weights and also suppose (and a big
suppose it is) that I have the (a) variogram(gamma).  If I  krige ignoring (w1
w2...) and weight the kriging weights (wk1 wk1 ...) with  (w1 w2) ie

   Answer= Sum(Value1*w1*wk1+Value2*w1*wk2+...)/Sum(w1*wk1+w1*wk2+...)

I get I some cases (zero nugget variogram and some negative weights)
unreasonable results e.g.

V1  w1 wk1
30   .1  1.2
50   .9  -.2
  answer=90

Unreasonable results are a well known result with negative weights and usually
indicate a (local) inconsistency between the data and the variogram but I think
the problem is exacerbated by not allowing for the weights w1.. in the kriging
matrix

My guess is that  the sample weights should be  coupled WITHIN  the kriging
equations something like:
   w1w1Gamma11 w1w2Gamma12 ..... ..... 1               wk1              w1Gamma1b
   w2w1Gamma21 w2w2Gamma22 ..... ....   1               wk2       =   w2Gamma2b
   ......                  ......                  .....  ..... 1                
..               .....
      1                        1                     ..... ......0
mu                      1

Before I work thru the math for my guess and code a solution  I would like input
on
    1) Has this problem been solved before?
    2) Is a C or Fortran or public .exe version of  the solution available (3d
preferred)

thanx

bob sandefur

Principal Geostatistician
Pincock Allen & Holt
International Minerals Consultants
274 Union Suite 200
Lakewood CO 80228
USA
303 914-4467  v
303 987-8907 f




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Hi  All

Could someone please advise me on a decent share/free ware package that has
the ability to run various forms of trend surface analysis on large data
sets (100 000+) e.g. residual, polynomial etc. (URL site for download would
be appreciated), and contour the data set afterwards.

The current software that I am using does not have this functionality built
in and I want to run a number of checks on various parameters that I have in
the data set.

Thank you

Mark Burnett
Evaluation Manager

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Have you checked out the R package available from www.lib.stat.cmu.edu/R and
its various add-on packages.  All free!

Best, Mark Hall


----- Original Message -----
From: "Burnett, Mark" <MBurnett@...>
To: <ai-geostats@...>
Sent: Tuesday, October 24, 2000 10:31 PM
Subject: GEOSTATS: Trend Surface Analysis software


> Hi  All
>
> Could someone please advise me on a decent share/free ware package that
has
> the ability to run various forms of trend surface analysis on large data
> sets (100 000+) e.g. residual, polynomial etc. (URL site for download
would
> be appreciated), and contour the data set afterwards.
>
> The current software that I am using does not have this functionality
built
> in and I want to run a number of checks on various parameters that I have
in
> the data set.
>
> Thank you
>
> Mark Burnett
> Evaluation Manager
>
> --
> *To post a message to the list, send it to ai-geostats@....
> *As a general service to list users, please remember to post a summary
> of any useful responses to your questions.
> *To unsubscribe, send email to majordomo@... with no subject and
> "unsubscribe ai-geostats" in the message body.
> DO NOT SEND Subscribe/Unsubscribe requests to the list!
>
>

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Hi Bob, long time no see

It is traditional in thin reef deposits (such as those
in South Africa) to use an accumulation value which is
length times grade. I have also seen similar composite
values used in iron ore where a weight times grade is
used as the principle variable.

These composite values generally give acceptable
semi-variograms and can then be kriged. The result is
(of course) an accumulation value and has to be
matched with a kriged length, weight or density
variable to achieve estimates in the original grade
units.

As a simple example, in a Wits Reef length times grade
is considered to be the 'natural' variable. This is
modelled and kriged. The width of the reef is also a
natural geological variable and this can be modelled
and kriged. Final grade is then kriged accumulation
divided by kriged width. Error on this is found using
the original combination of relative variances
suggested by Matheron.

This avoids all problems of messing around with
kriging systems and/or the kriging weights.

All of the above is predicated on your "weights" being
a physical phenomenon. If you are talking about
conceptual weights, then you probably need something
like "soft kriging" with a Bayesian input.

Isobel Clark
http://uk.geocities.com/drisobelclark


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Sorry folks about messing up the address for Stat Lib, it is:

http://lib.stat.cmu.edu/

Best, Mark Hall


----- Original Message -----
From: <abedini@...>
To: "Mark Hall" <hall@...>
Sent: Thursday, October 26, 2000 1:55 AM
Subject: Re: GEOSTATS: Trend Surface Analysis software


>
> Dear Mark
>
> I tried to connect to the URl which you provided receiving the following
> reply. Are you sure the address is correct?
>
> Thanks
> Abedini
>
> While trying to retrieve the URL: http://www.lib.stat.cmu.edu/
>
> The following error was encountered:
>
> Unable to determine IP address from host name for www.lib.stat.cmu.edu
> The dnsserver returned:
>
> Name Error: The domain name does not exist.
> This means that:
>
>  The cache was not able to resolve the hostname presented in the URL.
>  Check if the address is correct.
>
> Your cache administrator is root.
>
>
>
> --------------------------------------------------------------------------
------
> Generated Wed, 25 Oct 2000 16:51:46 GMT by proxy.shirazu.ac.ir
> (Squid/2.3.STABLE3)
>
>
>

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26th Oct., 2000

Dear Dr Isobel clark,

I was made part  the list of geostats from yesterday only and it is my
good fortune to see your reply in my first message. I had the opportunity
of corresponding with you on geostatistics during 1983-86.

Currently I am working with iron ore mines of Tata Steel in India. The
ore is won by opencast mining method with 12m high benches. The iron
ore consists of several types of ores each having definable quality
in terms of Fe, Al2O3 and SiO2; and physical characterisics such as
hard ore, soft ore, flaky ore, bluedust etc. making them to be
processed in wet and dry methods. In such a case, using all the iron ore
samples in kriging is leading to over=estimation of lean grade ores
and under-estimation of high grade ores if one sees block-wise. This
type of estiamtes are not acceptable to the production staff. Hence
I used variogram parameters of the entire iron ore samples to specific
ore type estimation for 12m benches with 100mx100m blocks using the
core smaples of that specific ore type, which satisfied the production
staff. Is the procedure correct? If not, can you please suggest a better
method?

In anticipation of your valuable advice.

With regards

Dr P.V. Rao


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Dear Dr. Isobel Clark,

I am new in geostats mail list.

I worked  in Romania many years in geoinformatics, to
use geomathematical and geostatistical methods for
several ores and different geological data, with
commercial, shareware and my own programs. Finally, I
learned ARC/INFO GIS on Silicon Graphics workstation.

In present, I am working as database programmer in
economical field in a private company, for a better
salary, which is a problem for geological domain in
Romania.

My wish is to continue with a better job in
geoinformatics (GIS, geostatistics). Please, give me
an advice to do this. For details see my home page
www7.ewebcity.com/geoinf

Thank you in anticipation.

Best wishes,

George Tudor


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On Wed, 25 Oct 2000, Mark Hall wrote:

> Have you checked out the R package available from www.lib.stat.cmu.edu/R and
> its various add-on packages.  All free!
>
> Best, Mark Hall

The "spatial" package can be used (Venables & Ripley, MASS 3rd
edition; package in the VR bundle on CRAN:

> x <- runif(100000)
> y <- runif(100000)
> z <- 5*x + 3*y + 0.5*x*y + 1*x*x + 1.5*y*y + rnorm(100000, 3, 2)
> summary(z)
    Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  -4.119   5.855   7.915   7.965  10.040  21.110
> library(spatial)
> tr2 <- surf.ls(2, x, y, z)
> str(tr2)
List of 11
  $ x   : num [1:100000] 0.111 0.793 0.581 0.868 0.254 ...
  $ y   : num [1:100000] 0.7505 0.7083 0.3539 0.0571 0.1982 ...
  $ z   : num [1:100000]  2.12 12.15  8.04  5.71 -1.65 ...
  $ np  : num 2
  $ f   : num [1:600000] 1 1 1 1 1 1 1 1 1 1 ...
  $ r   : num [1:21] -3.16e+02 -3.67e-01 -1.82e+02 -1.05e+02 -7.89e-03 ...
  $ beta: num [1:6] 7.753 3.101 0.273 2.376 0.127 ...
  $ wz  : num [1:100000] -4.620  1.400  0.449 -2.569 -6.682 ...
  $ rx  : num [1:2] 6.04e-06 1.00e-00
  $ ry  : num [1:2] 2.71e-05 1.00e-00
  $ call: language surf.ls(np = 2, x = x, y = y, z = z)
  - attr(*, "class")= chr "trls"
> trsurf2 <- trmat(tr2, 0, 1, 0, 1, 100)
> image(trsurf2)
> contour(trsurf2, add=T)
> tr3 <- surf.ls(3, x, y, z)
> image(trsurf2)
> contour(trsurf3, add=T)

However, R does all its work in memory, so I needed a heap size of 32M to
complete the quadratic trend, and over 40M for the cubic. If this is OK,
then the surf.ls() function and trmat() to generate predictions will do
what you need. If you need predictions for other points than a grid over
your study area, you need to look at the way trmat() works - ask if you
need help.

Best wishes,

Roger

>
> ----- Original Message -----
> From: "Burnett, Mark" <MBurnett@...>
> To: <ai-geostats@...>
> Sent: Tuesday, October 24, 2000 10:31 PM
> Subject: GEOSTATS: Trend Surface Analysis software
>
>
> > Hi  All
> >
> > Could someone please advise me on a decent share/free ware package that
> has
> > the ability to run various forms of trend surface analysis on large data
> > sets (100 000+) e.g. residual, polynomial etc. (URL site for download
> would
> > be appreciated), and contour the data set afterwards.
> >
> > The current software that I am using does not have this functionality
> built
> > in and I want to run a number of checks on various parameters that I have
> in
> > the data set.
> >
> > Thank you
> >
> > Mark Burnett
> > Evaluation Manager
> >
>

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@...
and: Department of Geography and Regional Development, University of
Gdansk, al. Mar. J. Pilsudskiego 46, PL-81 378 Gdynia, Poland.

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Thank you very much.

Your suggestion will be a way for my action.
My message it was already in ai-geostats mail list
and I hope to receive an advice from another
people.

Thank you again.

George Tudor


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If you guys are that desperate I published a program
in Computers and Geosciences in 1977 (I think). The
reference will be in
http://uk.geocities.com/drisobelclark/resume/publications.html

It was called SNARK and was for 3-d data.

Trend Surface Analysis is basically just ordinary
least squares. Any stat package which does least
squares regression should do all the relevant tests as
well.

The `theory' of PTSA and Analysis of Variance testing
is in Practical Geostatistics 2000, Chapter 7.

If you are willing (or allowed) to share your data
with the world, contact me and I'll turn it into a
valid file for the free 'book' software

http://uk.geocities.com/drisobelclark/PG2000_demo.html

Isobel Clark
+27 11 726 3729

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On 26 Oct 2000 08:25:06 EDT Patrick.J.Doran@... (Patrick J.
Doran) writes:

Consider looking at the paper:
Englund, E.J. 1990. A Variance of Geostatisticians. J. Math. Geology.
vol. 22, no. 4, pp. 417-455.
The paper describes an experiment in which 12 geostatisticians analyzed
the same data set, and then the results were compared on over a dozen
measures of estimation quality.  You might find some ideas in the
different measures of estimation quality. Moreover, you might see that
such a comparison would be highly dependent on the methods used to
interpolate values.

Charlie Kufs

~~~~~        TERRABYTE CORPORATION
~~~~~        Statistics, Data Mining, and Modeling
~~~~~        Applied to Solving Environmental Problems
~~~~~        http://terrabyte.ws
~~~~~        terrabyte@...

________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk!  For your FREE software, visit:
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2th Oct., 2000

Dear Dr Isobel Clark,

Thanks for your advice on iron ore deposit.  I have a further quiery
to you on the same subject.

You may appreciate that when we take samples (let us say 3m length)
along the vertical boreholes for each 12m bench height, different
ore types with varying lengths willb e encountered. In such a case,
when the mid-slice plans are prepared, usually the maximum length of
ore (core length) is designated in the slice plans. When the variogram
has to be calculated for 12m samples how to composite the radicals
for a given ore type?  if all the samples falling within 12m bench
height are taken for compositing, then the sample assay value don't
truly represent the designated ore type in the slice.

I seek your advice on this please.  You may please note that I do not
have access to internet at my place of work, which is definitely a
constraint in reviewing the published literature.


Dr P.V. RAO
Dy. Divisional Manager (planning)
Tata Steel, India
----------------------------------------------------------------------


On Thu, 26 Oct 2000, [iso-8859-1] Isobel Clark wrote:

> Dear Dr Rao
>
> How lovely to hear from you.
>
> In dealing with an area with several sub-populations
> of different geology, it is always best to use only
> the samples of the relevant geology.
>
> It would improve the estimation further if you can:
>
> (a) produce a semi-variogram model for each ore type
>
> (b) allow for the skewed nature of the data by using
> (say) a modified lognormal transformation.
>
> We have followed this pattern successfully in iron ore
> deposits in South Africa and in the USA.
>
> Let me kno wif I can be of any more help. Perhaps you
> would also like to visit our 'professional' Web pages
> at http://www.stokos.demon.co.uk
>
> With best regards
> Isobel Clark
>
>
>
> ____________________________________________________________
> Do You Yahoo!?
> Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk
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