<div dir="ltr">As reported at OSGeo/PROJ-data [1] and also found on stackexchange 5 years ago [2], it seems it is not possible to install libproj9 in a cross-compilation scenario:<div><br><div>[1] <a href="https://github.com/OSGeo/PROJ-data/issues/94">https://github.com/OSGeo/PROJ-data/issues/94</a></div></div><div>[2] <a href="https://askubuntu.com/questions/997277/multiarch-issue-with-packages-marked-as-supporting-all-architectures">https://askubuntu.com/questions/997277/multiarch-issue-with-packages-marked-as-supporting-all-architectures</a></div><div><br></div><div>When using proj in a multi-architecture environment (compiling cross-platform), the `proj-data` debian package does not exist.  The stackexchange post [2] has some hacky solutions on how to get around this issue.  I was trying to use <a href="https://github.com/cross-rs/cross">https://github.com/cross-rs/cross</a> 's docker image, and inside install proj with:</div><div><br>`docker run --rm -it <a href="http://ghcr.io/cross-rs/aarch64-unknown-linux-gnu:latest`">ghcr.io/cross-rs/aarch64-unknown-linux-gnu:latest`</a><br><br>```bash<br>dpkg --add-architecture arm64<br>apt-get update<br><br>apt show libproj9:arm64<br># shows     Depends: proj-data, libc6 (>= 2.17)<br><br>apt-get install -y libproj9:arm64<br># The following packages have unmet dependencies:<br>#  libproj9:arm64 : Depends: proj-data:arm64 but it is not installable<br><br>apt-get install -y proj-data:arm64<br># E: Package 'proj-data:arm64' has no installation candidate<br>```<br><br>Thanks!<br></div></div>