Thanks Stacho That is a good solution. It is appropriate that previews are ignored when calculating map extents. My experimental use case was to have a generic preview only map that I could then select in tandem with (non-previewed) maps, with the extents determined by the (non-previewed) maps. It was an idea to allow further ‘modularisation’ and standardisation of my datasets. It is easy to arrange map definitions to give the same effect, just have to make sure there is a non-previewed map in each. And as you suggest, a ‘preview’ that contributes to map extent definition can be emulated with map-fg and hiding all symbols. Impressed by the time and effort you are putting in. Much appreciated. Bruce From: Therion <therion-bounces@speleo.sk> On Behalf Of Stacho Mudrak Sent: Tuesday, 5 October 2021 10:16 To: List for Therion users <therion@speleo.sk> Subject: Re: [Therion] Selecting map defined with preview only causes error Hi Bruce, thanks for pointing it out. I have tried to allow map containing only previews, but there were apparently a lot of subsequent issues with its zero dimensions. Normally, previews are ignored when calculating the extent of a map. So I have modified the error message according to your suggestion. I assume the same map can be generated using a single map-fg color and hiding all symbols. Or am I missing something? S. On Mon, 4 Oct 2021 at 06:54, Bruce Mutton <bruce@tomo.co.nz <mailto:bruce@tomo.co.nz> > wrote: Hello Team I think this may be a bug. Selecting a map with only previews inside of it is causing an error, where possibly it should not. And if it is by design that it triggers an error, then the message it gives is not helpful. A better message would be “map cannot contain only previews” The error message. therion.exe: error -- GreenlinkArea/INDEXGLMESM_System.th [164] -- incompatible map projection -- SwissM_PlanMap@GLMESM_system The map definition. map GLMESMPreviewOnlyMap -projection plan preview below SwissM_PlanMap@GLMESM_system #map preview below DwarfsDoorPlanMap@GLMESM_system #map preview below MiddleEarthPlanMap@GLMESM_system #map endmap GLMESMPreviewOnlyMap The maps all have -projection plan explicitly defined, and the error is unchanged if I remove the projection option from the definition above. The thconfig. select QEII-01GreenLinkPlanCL select QEII-01GreenLinkPlan select GLMESMPreviewOnlyMap I have selected three maps, two contain valid maps, and one contains only previews. If I remove one of the ‘preview below’ statements preceding any of the previewed maps, the project compiles as expected. If I try to type the preview below directly into the thconfig, there is an error also, but I suspect this might be by design. Using 6.0.3, but am not assuming this was introduced recently. I have never tried it before. Regards Bruce _______________________________________________ Therion mailing list Therion@speleo.sk <mailto:Therion@speleo.sk> https://mailman.speleo.sk/listinfo/therion