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Martin Desruisseaux commented on SIS-212: ----------------------------------------- Hello Joseph In my understanding, the next step would be to write a document describing the project that you would like to do. You can copy and edit elements from this page as you wish. Instructions are available there: http://community.apache.org/gsoc.html The document could be written in a Google doc, or on a SIS wiki page (https://cwiki.apache.org/confluence/display/SIS/SIS+Wiki), or in other ways as you prefer. We could propose modifications and do some cycles until the proposal is ready for submission on the Google web site. Would this approach be okay? > Coordinate operation methods to implement > ----------------------------------------- > > Key: SIS-212 > URL: https://issues.apache.org/jira/browse/SIS-212 > Project: Spatial Information Systems > Issue Type: Task > Components: Referencing > Affects Versions: 0.6 > Reporter: Martin Desruisseaux > Assignee: Martin Desruisseaux > Labels: gsoc2016, java, mentor > Fix For: 0.6, 0.7 > > > This is an umbrella task for some coordinate operation methods not yet > supported in Apache SIS. Coordinate operations include _map projections_ > (e.g. Transverse Mercator, Lambert Conic Conformal, _etc._), _datum shifts_ > (e.g. transformations from NAD27 to NAD83 in United States), transformation > of vertical coordinates, _etc_. We can of course not list all possible > formulas that we do not support, but this JIRA task lists at least some of > the operations listed in the EPSG guidance notes. > The main material for this work is the EPSG guidance notes, which can be > downloaded freely from the following site: > {panel} > IOGP Publication 373-7-2 – Geomatics Guidance Note number 7, part 2 > Coordinate Conversions and Transformations including Formulas > http://www.epsg.org/GuidanceNotes > {panel} > Google summer of code students interested in this work would need to be > reasonably comfortable with the Java language (but not necessarily with the > JDK library at large, since this work uses relatively few JDK classes outside > {{Math}}), and in mathematic. In particular, this work requires a good > understanding of _affine transforms_: their representation as a matrix, and > how to map a term in a formula to a coefficient in the affine transform > matrix. > Apache SIS has one advanced feature which is not easily found in popular > geospatial software or text books: the capability to compute the _derivative_ > (or more precisely, the _Jacobian_) of a transformation at a given point. > Implementation of this feature requires the capability to find the analytic > derivative of a non-linear formula and to simplify it. > Implementations of those formulas take place in one of the > {{org.apache.sis.referencing.operation}} sub-packages ({{projection}} or > {{transform}}). Implementations of JUnit test happen partially in Apache SIS, > and partially in the ["conformance module" of the GeoAPI > project|http://www.geoapi.org/geoapi-conformance/index.html], if possible > through the Geospatial Integrity of Geoscience Software (GIGS) tests. -- This message was sent by Atlassian JIRA (v6.3.4#6332)