<div class="gmail_quote">Dear ESP-r Users, I want to define the zones using the clicking on grid points option. when I click "e" and then "save the zone data" this comment is appear: "Negative or zero zone volume detected. Vertex information maybe in error or surfaces incomplete." I'm almost sure that I selected the points correctly and on right direction, same as what is done in the cookbook page 57. But I also changed the direction to see if anything else happened? The result was the same! Although I can continue creating other zones, but when I exit from the click on facility only the last zone is appeared in the window. However the related items such as surface attributes, etc for this zone are editable,when I want to change to another zone, the program crashes and write this message: result of XReadBitmapFile 0 1063 787 15 15 get region is 0 330 1007 457 result of XReadBitmapFile 0 1063 787 15 15 get region is 0 330 1007 457 result of XReadBitmapFile 0 1063 787 15 15 get region is 0 330 1007 457 result of XReadBitmapFile 0 1063 787 15 15 get region is 0 330 1007 457 result of XReadBitmapFile 0 1063 787 15 15 get region is 0 330 1007 457 Fatal error: In ../zones/exam.geo expecting 4 items (insolation data) in... 0.00000 4.00000 0.00000 I use the esp-r 11.5 in UBUNTU. Any advices is appreciated, Best, Mostapha Sadeghipour </div>