Freeview reception at SO16 9BU

Terrain between SO169BU and Freeview masts

Fatal error: Uncaught DivisionByZeroError: Division by zero in /var/www/html/ukfree.tv/public/services/predict/getHeightFromImage.php:294 Stack trace: #0 /var/www/html/ukfree.tv/public/services/predict/getHeightFromImage.php(270): services\predict\getHeightFromImage->pixelLineOfSightEx() #1 /var/www/html/ukfree.tv/public/services/predict/terrainMap.php(177): services\predict\getHeightFromImage->pixelLineOfSight() #2 /var/www/html/ukfree.tv/public/services/predict/showTerrainGraphics.php(105): services\predict\terrainMap->setTX() #3 /var/www/html/ukfree.tv/public/services/predict/showTerrainGraphics.php(80): services\predict\showTerrainGraphics->mainUncached() #4 /var/www/html/ukfree.tv/public/services/predict/showTerrainGraphics.php(49): services\predict\showTerrainGraphics->mainEntryPoint() #5 /var/www/html/ukfree.tv/public/application/routepredict.php(43): services\predict\showTerrainGraphics->getEntryPoint() #6 /var/www/html/ukfree.tv/public/framework/routetoRouter.php(186): application\routepredict->execute() #7 /var/www/html/ukfree.tv/public/framework/routetoRouter.php(74): framework\routetoRouter->execute() #8 /var/www/html/ukfree.tv/public/index.php(8): framework\routetoRouter->__construct() #9 {main} thrown in /var/www/html/ukfree.tv/public/services/predict/getHeightFromImage.php on line 294

What do the map symbols mean?

 location on line-of-sight,  Selected location,  Freeview transmitter,  Freeview light transmitter,  Engineering/fault today.