feat: added SIS_DATA variable

Author: MathiasVDA

Dockerfile

@@ -7,8 +7,8 @@ FROM eclipse-temurin:21-jre-alpine AS base
 ARG JENA_VERSION=5.4.0
 ENV JENA_VERSION=${JENA_VERSION}
 
-# jq needed for tdb2.xloader, wget for downloading files
-RUN apk add --update bash ca-certificates coreutils findutils jq pwgen ruby wget && rm -rf /var/cache/apk/*
+# jq needed for tdb2.xloader, wget for downloading files, unzip for SIS datasets
+RUN apk add --update bash ca-certificates coreutils findutils jq pwgen ruby wget unzip && rm -rf /var/cache/apk/*
 
 # Config and data
 ENV FUSEKI_BASE=/fuseki-base
@@ -36,6 +36,22 @@ RUN echo "Downloading GeoSPARQL extension ${JENA_VERSION}..." && \
     "https://repo1.maven.org/maven2/org/apache/jena/jena-fuseki-geosparql/${JENA_VERSION}/jena-fuseki-geosparql-${JENA_VERSION}.jar" && \
     echo "GeoSPARQL extension downloaded"
 
+# Download and install Apache SIS binary distribution
+ENV SIS_HOME=/apache-sis
+RUN echo "Downloading Apache SIS binary distribution ${SIS_VERSION}..." && \
+    wget -O /tmp/apache-sis-${SIS_VERSION}-bin.zip \
+    "https://dlcdn.apache.org/sis/${SIS_VERSION}/apache-sis-${SIS_VERSION}-bin.zip" && \
+    echo "Extracting Apache SIS..." && \
+    cd /tmp && \
+    unzip -q apache-sis-${SIS_VERSION}-bin.zip && \
+    mv apache-sis-${SIS_VERSION} $SIS_HOME && \
+    rm apache-sis-${SIS_VERSION}-bin.zip && \
+    echo "Apache SIS binary distribution installed"
+
+# Set SIS_DATA environment variable for coordinate reference system support
+ENV SIS_DATA=$FUSEKI_BASE/SIS_DATA
+ENV PATH=$PATH:$SIS_HOME/bin
+
 # Download, extract and install Jena tools
 RUN echo "Downloading Apache Jena ${JENA_VERSION}..." && \
     wget -O jena.tar.gz "https://dlcdn.apache.org/jena/binaries/apache-jena-${JENA_VERSION}.tar.gz" && \
@@ -70,7 +86,10 @@ RUN mkdir -p $FUSEKI_BASE/databases
 
 # Set permissions to allow fuseki to run as an arbitrary user
 RUN chgrp -R 0 $FUSEKI_BASE \
-    && chmod -R g+rwX $FUSEKI_BASE
+    && chmod -R g+rwX $FUSEKI_BASE \
+    && chgrp -R 0 $SIS_HOME \
+    && chmod -R g+rX $SIS_HOME \
+    && chmod -R g+rwX $SIS_HOME/log
 
 # Tools for loading data
 ENV JAVA_CMD='java -cp "$FUSEKI_HOME/fuseki-server.jar:/javalibs/*"'

README.md

@@ -17,7 +17,8 @@ This Docker container provides Apache Jena Fuseki with built-in GeoSPARQL suppor
 ### Features
 
 - 🌍 **Spatial Queries**: GeoSPARQL 1.0 support for geometric and topological operations
-- 🔍 **Text Search**: Integrated Lucene indexing for SKOS labels and RDF literals
+- �️ **Coordinate Systems**: Apache SIS tools for downloading EPSG datasets
+- �🔍 **Text Search**: Integrated Lucene indexing for SKOS labels and RDF literals
 - 📊 **High Performance**: TDB storage with optimized configurations
 - 🔐 **Secure**: Built-in authentication with configurable admin password
 - 🐳 **Docker Ready**: Production-ready container with proper security settings
@@ -26,7 +27,7 @@ This Docker container provides Apache Jena Fuseki with built-in GeoSPARQL suppor
 
 More information about the GeoSPARQL implementation of Apache Jena Fuseki can be found in the [official documentation](https://jena.apache.org/documentation/geosparql/).
 
-Limitation: coordinate transformations are currently an issue. Distance calculation seems to be related to this. This probably has something to do with SIS_DATA.
+**Note**: This container includes Apache SIS command line tools to enable download of EPSG datasets. The SIS_DATA environment variable is configured to a directory inside /fuseki-base (recommended to as docker volume). It seems that this is insufficient for Jena Fuseki to properly transform coordinates or calculate metric distances for WGS84 coordinates.
 
 ## Usage
 
@@ -192,6 +193,14 @@ The container uses several configuration files in the `config/` directory:
 - `shiro.ini` - Security and authentication configuration
 - `docker-entrypoint.sh` - Container initialization script
 
+### Apache SIS Configuration
+
+The container includes Apache SIS EPSG datasets for coordinate reference system support:
+
+- **SIS_DATA Path**: `/fuseki-base/SIS_DATA`
+- **EPSG Database**: Provides access to thousands of coordinate reference systems
+- **Automatic Detection**: SIS automatically detects and uses the EPSG database for transformations
+
 You can override these by mounting your own configuration files:
 
 ```bash