slow rendering when exporting a complex area feature

[thommyboy]

dear customer support,
i load some srtm/dem/tif tiles and would like to export a special area. when i choose "draw a box" from "export bounds" everything gets exported pretty fast. but when i load a shp file including country-borders and use "select all features with digitizer" and then "crop to selected area features" from "export bounds" the export is very slow- several minutes compared to 5 secs for the "same" area. is that normal behaviour or do i do something wrong?
regards
tom

[global_mapper]

Tom,

That is normal and depends heavily on the complexity of the area features that you are cropping your export to. Performing a point-in-polygon operation for each exported pixel against the crop polygons can be very slow compared to a simple bounding box check for the normal box export.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[thommyboy]

ok, makes sense to me and my area contains lot's of small islands. maybe one more question on this topic (i'm pretty new to GM)
i load high definition data but finally don't need high definition raster export. will changing the "export at a fixed scale" setting speed things up?
exporting just a bounding box could work for me too- but i would need a given aspect ratio for that- can i somehow achieve that?

and thanks for your quick reply by the way- this customer support is outstanding compared to many i know...

[global_mapper]

Exporting at a fixed scale won't speed things up, but if you don't need the full definition of your crop areas, what you can do to speed things up dramatically is select those areas with the Digitizer Tool, then right-click and select the option to simplify/reduce the areas. You will then get areas with less vertices that still maintain the same basic shape that you can then crop to and the operation should be much faster.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com