Ich hatte nix besseres zu tun, hier regnet es in Strömen 
[{"id":"4a0e027c2d05bed7","type":"ui_gauge","z":"7251fa91e7e8f813","name":"Luftdruck NN","group":"6785c9b7f3b3e0bd","order":3,"width":6,"height":6,"gtype":"gage","title":"Luftdruck NN","label":"hPa","format":"{{msg.payload}} hPa","min":"900","max":"1060","colors":["#ff0000","#00ff00","#00ff00"],"seg1":"980","seg2":"1100","diff":false,"className":"","x":990,"y":540,"wires":[]},{"id":"8d3879dca83fb2d6","type":"ui_text","z":"7251fa91e7e8f813","group":"b8db3199.f0dbe","order":19,"width":0,"height":0,"name":"Luftdruck NN","label":"Luftdruck NN","format":"{{msg.payload}}.hPa","layout":"row-spread","className":"","style":false,"font":"","fontSize":"","color":"#000000","x":1150,"y":540,"wires":[]},{"id":"a041aab0780f245f","type":"function","z":"7251fa91e7e8f813","name":"Luftdruck NN","func":"let druck = msg.payload.pressure_hPa | 2;\nlet hoehe = global.get (\"GV_Höhe\");\nlet hk = hoehe/10;\nlet druckNN = druck + hk;\nmsg.payload = druckNN\n\n\nreturn msg;\n\n/*\nHöhenkorrektur: 500 m / 10 = 50 hPa\nLuftdruck auf NN = 950 hPa + 50 hPa = 1000 hPa\n*/","outputs":1,"timeout":0,"noerr":0,"initialize":"","finalize":"","libs":[],"x":830,"y":540,"wires":[["8d3879dca83fb2d6","4a0e027c2d05bed7","68e4cef0a8851b3d"]]},{"id":"68e4cef0a8851b3d","type":"debug","z":"7251fa91e7e8f813","name":"debug 171","active":false,"tosidebar":true,"console":false,"tostatus":true,"complete":"true","targetType":"full","statusVal":"payload","statusType":"auto","x":990,"y":600,"wires":[]},{"id":"6785c9b7f3b3e0bd","type":"ui_group","name":"Test","tab":"e138f72fc5a1808e","order":3,"disp":true,"width":"12","collapse":false,"className":""},{"id":"b8db3199.f0dbe","type":"ui_group","name":"Temperature","tab":"deee53a800de461d","order":4,"disp":true,"width":"6","collapse":true,"className":""},{"id":"e138f72fc5a1808e","type":"ui_tab","name":"Test","icon":"build","order":45,"disabled":false,"hidden":false},{"id":"deee53a800de461d","type":"ui_tab","name":"Info","icon":"mi-info","order":2,"disabled":false,"hidden":false}]
Ich bekomme den Druck aus eimem BME280, daher wirst du den Eingangs Payload und den get.global für die Höhe ändern müssen.