python - Why are the images produced from a numpy array incorrect -

i have written python program takes x, y, c values (c being charge) particle detector , converts them grey scale heat map images. example of program produces below. should shown several clusters of grey-white areas on black background representing particle collisions screen. know because pixelman program use particle detector shows looks like, program lets without detector plugged in.

def heatmap(self):     xlist=[]     ylist=[]         clist=[]     directory = str(self.varrun.get())     if directory == "none selected" :         tkmessagebox.showinfo("error", "no run selected")     else:         filename = askopenfilename(title = "choose new image import", initialdir=directory)         if filename[-4:] != ".txt":             tkmessagebox.showinfo("error", "you must select .txt image")         else:             open(filename,'r') f:                 reader=csv.reader(f,delimiter='\t')                 x, y, c in reader:                     xlist.append(int(x))                     ylist.append(int(y))                      clist.append(float(c))           #np.meshgrid(xlist,ylist)          maxc = max(clist)          array = np.zeros((256, 256))         in range (0, len(xlist)-1):             rgbvalue = (float(clist[i]) / float(maxc)) * 255             array[ylist[i],xlist[i]] = rgbvalue         array = sp.ndimage.zoom(array, 2, order=0)         imagefromarray = image.fromarray(array, "1")          imagefromarray.save(str(filename[:-4] + ".png"))         newphoimg = imagetk.photoimage(imagefromarray)         self.imageviewer.configure(image=newphoimg)         self.imageviewer.image = newphoimg 

the routine asks file , displays above. discovering why image not form appreciated. have checked xlist, ylist , clist correct values inserted them text file don't know goes wrong there. sample of input file is:

2   0   43.000000 3   0   65.000000 4   0   67.000000 5   0   33.000000 7   0   44.000000 8   0   102.000000 9   0   59.000000 10  0   31.000000 11  0   42.000000 12  0   29.000000 13  0   125.000000 14  0   115.000000 ...  247 255 38.000000 

obviously continues way down y values of 255

now solved 2 images produced were:

as mentioned in comment, line

    imagefromarray = image.fromarray(array, "1") 

is suspect. converting floating point array 1-bit image (see http://effbot.org/imagingbook/concepts.htm#mode).

try changing line to

    imagefromarray = image.fromarray(array).convert('l') 

then imagefromarray 8-bit image can saved png file.