[geotf] ENU frame projection error

[rikba]

The orthographic projection causes a non-neglectable error when converting geodetic to ENU coordinates.

The current projection should be replaced by a topocentric projection, i.e.,

char enu_proj[250];
sprintf(enu_proj, "+proj=topocentric +ellps=WGS84 +lon_0=%.15f +lat_0=%.15f +h_0=%.15f", lon, lat, alt);
spatial_ref->importFromProj4(enu_proj);

See https://proj.org/operations/conversions/topocentric.html

Unfortunately, this is only available with PROJ4 >= 8.0.0 which is only available with Ubuntu 22.04.

For now one can use the deprecated geodetic_utils for example, but should correct the bug #36

[Jaeyoung-Lim]

@rikba I tried using the topocentric projection with gdal, but was not able to convert coordinates between WGS84 (EPSG:4326)

  local_spatial_ref_ = std::make_shared<OGRSpatialReference>();
  char enu_proj[250];
  sprintf(enu_proj, "+proj=topocentric +ellps=WGS84 +lon_0=%.15f +lat_0=%.15f +h_0=%.15f", global_reference_longitude_, global_reference_latitude_, global_reference_altitude_);
  local_spatial_ref_->importFromProj4(enu_proj);

  auto wgs84_ref = std::make_shared<OGRSpatialReference>();
  wgs84_ref->importFromEPSG(4326); // WGS84 EPSG 4326

  OGRPoint p;
  p.setX(msg.current.lat);
  p.setY(msg.current.lon);
  p.setZ(msg.current.alt);
  p.assignSpatialReference(wgs84_ref.get());

  p.transformTo(local_spatial_ref_.get());
  Eigen::Vector3d target_coordinates(p.getX(), p.getY(), p.getZ());

Error message:

 ERROR 1: PROJ: pipeline: Pipeline: Mismatched units between step 2 and 3

Any ideas / pointers you can suggest to solve this problem would be helpful!

[rikba]

Sorry, but I have not worked with it since them. You are testing it on 22.04?

[Jaeyoung-Lim]

@rikba Yes!