iphone - Core Plot generating a flat line, X or Y range incorrect? -


i using core plot plot 2000 data points. load fine, see smooth line:

alt text

i not sure why flat line rather showing graph of of values in large range. have done wrong setting plot space?

cpxyplotspace *plotspace = (cpxyplotspace *)graph.defaultplotspace; plotspace.allowsuserinteraction = no; plotspace.xrange = [cpplotrange plotrangewithlocation:cpdecimalfromfloat(0.0) length:cpdecimalfromfloat(num_points)]; plotspace.yrange = [cpplotrange plotrangewithlocation:cpdecimalfromfloat(0.0) length:cpdecimalfromfloat(num_points)];

here numberforplot method well:

-(nsnumber *)numberforplot:(cpplot *)plot field:(nsuinteger)fieldenum recordindex:(nsuinteger)index  {     nsnumber *num = [sortedarray objectatindex:index];     return num; }

any ideas doing wrong here?

there couple of different issues here:

  1. the plot space ranges given in data coordinates. can either calculate ranges or use plot space method -scaletofitplots: calculate them automatically. see answer your related question on core plot discussion board how calculate ranges manually.

  2. your -numberforplot:field:recordindex: ignores field parameter. you're returning same value both cpscatterplotfieldx , cpscatterplotfieldy, hence diagonal line.

one possible solution:

-(nsnumber *)numberforplot:(cpplot *)plot field:(nsuinteger)fieldenum recordindex:(nsuinteger)index  {     nsnumber *num = nil;      switch ( fieldenum ) {     case cpscatterplotfieldx:         num = [nsnumber numberwithunsignedinteger:index];         break;     case cpscatterplotfieldy:         num = [sortedarray objectatindex:index];         break;     }      return num; }

eric


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