[Gvsig_english] spatial query rules in Selection by layer tool

[José Antonio Canalejo Alonso]

Hello Ernesto,
thank you very much for this good set of layers. Maybe we can also use them to 
test the topology extension [1], [2].
I think, it is really interesting what you are proposing here with specific data 
and workflows. You are probably the best person to coordinate this working 
group. I would like to join this group if you could coordinate us. Is it ok for 
you?
Do we have a web platform where we could document our results and look into the 
matter ourselves? Maybe we can use a google.doc to work together on this? We 
will give later our results to the project.
Nice to hear from you.
José

[1] http://www.gvsig.org/web/projects/gvsig-desktop/devel
[2] 
http://www.gvsig.org/web/projects/gvsig-desktop/docs/user/ext/topologia/topologia-0-1.0/topology-0-1-0/view?set_language=en


 --
José Antonio Canalejo Alonso
http://www.csgis.de




________________________________
De: ernesto sferlazza <e.sferlazza at gmail.com>
Para: gvsig_internacional at listserv.gva.es; martinez_lucpal at gva.es
Enviado: vie,20 mayo, 2011 14:07
Asunto: Re: [Gvsig_english] spatial query rules in Selection by layer tool

> From: Luc?a Mart?nez <martinez_lucpal at gva.es>
> Hello Ernesto,
> I was also testing every option of the tool.
> I am afraid but we do not have enough documentation to determine the
> exact behavior of some of the options.
> As you say, they may need some adjustments.


Hello, I have created a set of layers almost complete, suitable to
perform tests on topological rules used in spatial query, implemented
in ArcGIS Desktop and in gvSIG.
The layers can be downloaded from url [1].

[1] http://sit.provincia.agrigento.it/scaricabili/temp/

The names of the layers are self explanatory (I hope): inputLines,
inputPolygons and inputPoints are the layers from which we want to
select features performing the spatial query; maskPoints, maskLines
and maskPolygons are the layers where we select features to be used as
comparison (example: select features from layer inputPolygons that
INTERSECT WITH selected features from layer maskLines).

The input theme's attribute table contains, among the other,  fields
R1, R2, ... , R32. From R1 to R13 they refer to the following ArcGIS
Desktop rules:

R1 = intersect
R2 = are within a distance of
R3 = contain
R4 = completely contain
R5 = contain (Clementini)
R6 = are identical to
R7 = touch the boundary of
R8 = share a line segment with
R9 = are crossed by the outline of
R10= have their centroid in
R11= are within
R12= are completely within
R13= are within (Clementini)

From R14 to R21 fields refer to the following gvSIG rules:
R14 = are the same as
R15 = are disjoint from
R16 = intersect with
R17 = touch
R18 = cross over
R19 = contain
R20 = are contained in
R21 = are on the top of

The other fields refer to the rules implemented in AdB-Toolbox
(developed from OpenJump), but I have not yet tested rules for this
software.

The meaning of the value for each rule is:
1: the feature from the input layer is selected when the rule is applied;
0: the feature from the input layer is NOT selected when the rule is applied;
9: depends on effective value of distance specified (i.e, not tested
for rule R2)
-99: the rule cannot be applied for the geometries involved in the
comparison   (for example polygons cannot be  contained in points or
in polylines).
The values have been obtained using the test I have performed on data,
therefore they are liable to contain mistakes.

I have found sometimes a strange or senseless behaviour applying some
of the rules implemented in gvSIG, so that actually I think that
spatial query in gvSIG is not yet quite reliable.
Developers and volunteers can perform their own tests to verify or to
rebut my assertions.
The data can be used to improve documentation, too.
Best regards

--
ing. Ernesto Sferlazza
responsabile nodo provinciale di Agrigento del SITR Sicilia
resp. gruppo Sistema Informativo Territoriale
Provincia regionale di Agrigento
sede istituzionale: piazza Aldo Moro, 1 - 92100 AGRIGENTO
sede operativa: via Acrone, 27 - 92100 AGRIGENTO
cell. 3392718463 (personale)
       3316874296 (aziendale)
tel. uff 0922593752
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