Calculate area solar radiation wrong value

Discussion created by temuujin_aav on Jun 18, 2014
hello?I am working on the drawing of the solar radiation map. My calculated value different from the results of our measurement value. I calculated value is 7226 - 36698 Wh/m2, measurement value is 609 - 4909 Wh/m2 .How do I fix this error?Please help me.And I was used SRTM DEM.
Pls help me!!!
thank you.