[SoC] Creation of new topological rules in gvSIG desktop - Final Report

Mon Aug 26 05:25:22 PDT 2019

 Thanks for your final report.

Helmut on behalf of the OSGeo GSoC admins

Am Mo., 26. Aug. 2019 um 14:16 Uhr schrieb Héctor <hectorth23 at gmail.com>:

> Dear community,
>
> The GSoC 2019 end has arrived and I share you the final report of my work
> during the coding period.
>
>
> *1. Title*
>
> Creation of new topological rules in gvSIG desktop
>
>
> *2. Software community*
>
> OSGeo, gvSIG
>
>
> *3. Abstract*
>
> This GSoC project consisted of implementing and integrating three new
> rules in the gvSIG topology framework to model spatial relationships that
> verify the integrity of the spatial information, validate the
> representations and correct posible errors. These three rules are Must Be
> Disjoint, Must Not Have Dangles and Must Be Larger Than Cluster Tolerance.
>
> The Must Be Disjoint rule requires that points be spatially separated from
> other points in the same layer, so any point that overlaps is an error. The
> action implemented to solve posible violations of this rule is
> deletePointsAction, which eliminates points that are not spatially
> separated.
>
> The Must Not Have Dangles rule requires that a line feature must touch
> line features from the same layer at both ends. An endpoint that is not
> connected to another line is an error, called dangle. One solution to this
> action is extendAction that extends the dangling end if they fix to other
> line features within a given distance by the user. Other solution is
> trimAction that trims dangling line features if a point of intersection is
> found within a given distance by the user. And another solution is
> snapAction that snaps dangling line features to the nearest line feature
> within a given distance by the user. Unlike the first solution, snapAction
> first tries to snap endpoints to the vertices, and secondly to the edge of
> line features.
>
> The Must Be Larger Than Cluster Tolerance rule requires that the vertices
> of each line or polygon feature must be spaced a distance larger than the
> tolerance established by the user. Vertices that fall within the tolerance
> are considered errors. This rule is mandatory for all topology. The
> simplest solution, called deleteFeatureAction, is to eliminate line or
> polygon features that collapse during the validation process. The other
> solution, deletePointsAction, modifies line or polygon features whose
> points collapse during the validation process.
>
>
>
> *4. Motivation*
>
> My main motivation behind this project was to be able to collaborate in
> the gvSIG topological framework development project to provide this
> application with greater functionality at the stage of processing and
> cleaning geographic data to be able to perform better and accurate data
> analysis, especially in Big data environments. Other motivations were:
>
> - Participate in an open source project.
>
> - Improve my programming skills.
>
> - Generate other skills around programming such as the repository for the
> code.
>
> - Way to generate open documentation of the work done.
>
> - Know the interaction between the open source community.
>
>
> *5. State of the Project before GSoC 2019*
>
> The gvSIG topology framework before my GSoC 2019 only allowed to apply
> some topological rules regarding an entity that does not contain a null
> geometry, that each polygon of a polygon layer always contains a point in
> another layer and that two polygon geometries do not overlap between them.
> In some of these rules it was still necessary to develop the appropiate
> actions to be able to apply them. Therefore, a good topological analysis
> could not be performed for the data sets to verify the integrity of the
> spatial information, validate representations and correct possible errors
> automatically.
>
>
> *6. Value of GSoC Project*
>
> With the three rules that I created and with their integration into the
> gvSIG topological framework, now it is posible to improve the data sets
> topological analysis and apply different actions to correct the features in
> an automated way.
>
>
> *7. Work to be done*
>
> There is still a little work to be done on the project. The tasks for the
> future are to finish developing the actions code so that they can be
> applied in data sets that can not create spatial indexes automatically. It
> would also have to adapt the Must Not Have Dangles rule code and of the
> extendAction and trimAction actions for data sets with multiline geometries
> as well as include the code part to be able to update two entities at the
> same time when the gvSIG bug is fixed.
>
>
> *8. Future opportunities*
>
> The gvSIG topological framework development project is still underway and
> there are still many other rules to be developed.
>
>
> *9. Links*
>
> *Work Product*
>
> Please test my code following instructions here
> <https://github.com/hecnita/gvsig-gsoc2019-topology/wiki/Work-Product>
>
> *Code Documentation*
>
> - Must Be Disjoint Rule
> <https://github.com/hecnita/gvsig-gsoc2019-topology/wiki/Rule-Must-be-disjoint>
>
> - Must Not Have Dangles Rule
> <https://github.com/hecnita/gvsig-gsoc2019-topology/wiki/Rule-Must-not-have-dangles>
>
> - Must Be Larger Than Cluster Tolerance Rule
> <https://github.com/hecnita/gvsig-gsoc2019-topology/wiki/Rule-Must-be-larger-than-cluster-tolerance>
>
> *Pull Requests*
>
> - Must Be Disjoint Rule
> <https://github.com/gvsig-sandbox/TopologyRuleMustBeDisjointPoint>
>
> - Must Not Have Dangles Rule
> <https://github.com/gvsig-sandbox/TopologyRuleMustNotHaveDanglesLine>
>
> - Must Be Larger Than Cluster Tolerance Rule
> <https://github.com/gvsig-sandbox/TopologyRuleMustBeLargerThanClusterTolerance>
>
> *Last GSoC 2019 commits*
>
> - Must Be Disjoint Rule
> <https://github.com/hecnita/TopologyRuleMustBeDisjointPoint/commit/73faef953f23d20a88fcc261b4aa51075e05306f>
>
> - Must Not Have Dangles Rule
> <https://github.com/hecnita/TopologyRuleMustNotHaveDanglesLine/commit/3f26bba25b3dedd697b9d91a4ee5c783f53d64bf>
>
> - Must Be Larger Than Cluster Tolerance Rule
> <https://github.com/hecnita/TopologyRuleMustBeLargerThanClusterTolerance/commit/ddf7deef47c1ded432b2cd8531364fd8c6c12198>
>
> *Project Documentation (Wiki Page)*
>
> Wiki Page
> <https://github.com/hecnita/gvsig-gsoc2019-topology/wiki/Creation-of-new-topological-rules-in-gvSIG-desktop>
>
> *Project sample*
>
> Image
> <https://github.com/hecnita/gvsig-gsoc2019-topology/blob/master/images/image.png>
>
>
> Thank you very much everyone for this opportunity and all your support. It
> has been a great experience working with the gvSIG association people and
> sharing the weekly work with the OSGeo community. These months have helped
> me to learn a lot.
>
> Best Regards
>
> Héctor Tundidor
> _______________________________________________
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> SoC at lists.osgeo.org
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