Hi Martin,
thanks for the response and info.
I tried something different and have therefore a general question of the
reprojection process.
I am using the maven dependencies org.apache.sis.core (v.1.0) and
org.apache.sis.non-free and I want to reproject a SIS DirectPosition2D point.
I assume that my WGS84 point is in lng / lat that's why I use a special
axisConvention.
So here my example:
CoordinateReferenceSystem sourceCRS = CRS.forCode("EPSG:4326");
CoordinateReferenceSystem targetCRS = CRS.forCode("EPSG:32632");
CoordinateReferenceSystem alternativCRSsource =
AbstractCRS.castOrCopy(sourceCRS).forConvention(AxesConvention.RIGHT_HANDED);
CoordinateOperation op = CRS.findOperation(alternativCRSsource, targetCRS,
null);
DirectPosition2D sisPoint = new DirectPosition2D(8.4036527, 49.0068901);
DirectPosition2D projPoint = (DirectPosition2D)
op.getMathTransform().transform(sisPoint, null);
System.out.println(projPoint.toString()); // POINT(456387.7786436868
5428393.033233286)
To get this run I need following packages:
import org.apache.sis.geometry.DirectPosition2D;
import org.apache.sis.referencing.CRS;
import org.apache.sis.referencing.crs.AbstractCRS;
import org.apache.sis.referencing.cs.AxesConvention;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
import org.opengis.referencing.operation.CoordinateOperation;
import org.opengis.referencing.operation.TransformException;
import org.opengis.util.FactoryException;
I found a similar example on https://sis.apache.org/book/en/developer-guide.html
I am wondering off the org.opengis.* packades and why I have to cast the op
object result from org.opengis.geometry.DirectPosition; to
org.apache.sis.geometry.DirectPosition2D;
The apache project I am working on is not allowed to use LGPL and I know this
packages from another geotools project.
So is my example correct? Under which license do the org.opengis packages run
which are apparently included in one of the sis dependencies (just to be save
in this part)
Thanks!
Florian
Am 08.03.20 um 21:49 schrieb Martin Desruisseaux:
Hello Florian, and welcome!
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Le 08/03/2020 à 21:17, Florian Micklich a écrit :
I am pretty new to Apache SIS but did already some coordinate transformations
like this example:
https://sis.apache.org/book/en/developer-guide.html#CoordinateOperations
Is there also a possibility to reproject other geometries like LineStrings and
Polygons or do I have to use a CoordinateSequens to reproject such kind of
types?
Yes, but not yet with a public, committed API. The support of geometries in
Apache SIS is a work in progress. Geometries are defined by the ISO 19107
international standard, which supports up to three-dimensional geometries with
curves. JTS can been seen as a subset of that standard for two-dimensional line
strings in Cartesian space. Our plan is to define an API based on ISO 19107,
then create wrappers around JTS objects for exposing those objects through that
API. That way the same API can also be used with ESRI API (another library
which can pretty much compete with JTS), and the API is ready for 3 dimensional
objects in the future.
But we are not yet there. In the meantime it is possible to do some operations
on JTS objects using the given class:
* org.apache.sis.internal.feature.jts.JTS
It has a static method like below:
* public static Geometry transform(Geometry geometry, CoordinateOperation
operation)
However everything in "internal" packages are not committed API; they may
change in any future SIS version. As said before we plan to provide this service in the
future through an API which work with JTS as well as with ESRI API and future libraries.
But we are not yet there and for now that internal API is the only way.
Is there an example to do a transformation with JTS geometry with SIS?
If "source" and "target" are two EPSG code as Strings, it could be:
CoordinateReferenceSystem sourceCRS = CRS.forCode(source);
CoordinateReferenceSystem targetCRS = CRS.forCode(target);
CoordinateOperation op = CRS.findOperation(sourceCRS, targetCRS, null);
Geometry original = ...;
Geometry converted = JRS.transform(original, op); // WARNING: internal
class, may change in any future version.
Regards,
Martin
