From time to time some issues are reported regarding a discrepancy in distance between JRC ECDIS types and NavStation Software. We did some testing in regard to this JRC issues (For clarification see the below screenshots). We did export NAVTOR formats also to SAM and FURUNO ECDIS types and did not encounter big differences in distances since they use the same calculation methods as we do.1 Scenario 1 Curved line:
2 NavStation presentation and distances^
^JRC ECDIS presentation. ECDIS imports the turn radius values as entered in NavSt. but does not take them in consideration when it comes to distance calculations. The Distance in JRC systems is measured from Wpt to WPT. This is an unrealistic display course alterations of 90 degrees and sharper can exclusively performed by vessels equipped with Azipods, Voith Schneider systems, or a vessel in manoeuvring mode using bow/stern thrusters.
3 Scenario 2.1 GC
We also discovered a difference in distance when it comes to voyages with 2 waypoints using GC and RL. We have non reported issues from other ECDIS manufacturers regarding a mismatch in calculated distances and for our own verification we uploaded a route made in NavStation into the JRC and into a SAM ECDIS. The result of the calculated distance in SAM was identical to the NavStation, The JRC ECDIS calculated a different result on both GC and RL. Please see pictures below for reference:
4 ^GC in NavStation 4103,8 NM
5 ^GC in SAM ECDIS 4103,79NM
^GC in JRC ECDIS 4091,6NM> difference = -12 NM
6 Scenario 2.2 RL
7 ^RL in NavStation 4283,6NM
8 ^RL in SAM ECDIS 4283,6NM
^RL in JRC ECDIS 4289,1 NM> difference = +6,6NM
The only solution we find to improve compatibility with JRC ECDIS systems is to add an alternative distance calculation (excluding curved line method). Like we did with the option to choose WPT 0 as departure WPT instead of WPT 1. However the difference in distance when using RL or GC requires further research. When it comes to the result of a calculation output NavStation for sure matches the majority of the ECDIS manufacturers.