When you use a float numbers in EMAN2, use it explicitly. That means add a 'f' postfix if you mean a float. For example,  use:

{{{
Dict params;
params["alt"] = 360.0f;
}}}
instead of:

{{{
Dict params;
params["alt"] = 360.0;
}}}
Because the number without postfix by default is double type. It's better to explicitly specifies the number as float explicitly to save a implicitly type conversion from double to float.