The error does not occur for. therion 6.3.4 (2025-04-08) cavern - Survex 1.4.17 therion 6.3.4+1f7444ab (2025-08-12) therion 6.3.4+ba4385e9 (2025-11-19) And for . therion 6.3.4+df4b6741 (2026-01-18) therion 6.3.4+999e03f9 (2026-02-21) I get. C:\Program Files\Therion\therion.exe: error -- Press ENTER to exit!./GreenlinkArea/./middleearthcave/INDEXMiddleEarthElev290.th [225] -- incompatible map projection -- MiddleEarthElev290Map .which is a different bug, previously reported, initially as https://github.com/therion/therion/issues/744. Bruce From: bruce@tomo.co.nz <bruce@tomo.co.nz> Sent: Sunday, 19 April 2026 08:59 To: 'List for Therion users' <therion@speleo.sk> Subject: map survey option now causes (fatal) error For a few maps in a few surveys I have been using the -survey option to constrain map statistics to match the underlying survey (page 34-35 of Therion Book). I think some recent version of Therion has broken this. The start of my map definition. map MiddleEarthElev290Map \ -title "Middle Earth and<br>Lower Greenlink Caves<br>Elevation looking 290 deg" \ -projection [elevation 290 deg] \ -survey MiddleEarth # survey option forces map statistics to match the survey The error reported. via Mapiah. C:\Program Files\Therion\therion.exe: error -- Press ENTER to exit!./GreenlinkArea/./middleearthcave/INDEXMiddleEarthElev290.th [579] -- invalid survey reference - MiddleEarth via XTherion C:\Program Files\Therion\therion.exe: error -- ./GreenlinkArea/./middleearthcave/INDEXMiddleEarthElev290.th [579] -- invalid survey reference -- MiddleEarth writing xtherion file ... done I am using. therion 6.3.4+d9c313ac (2026-03-29) - using Proj 9.8.0, compiled against 9.8.0 Anyone else noticed this? Thanks Bruce