# mne.channels.read\_custom\_montage('128+8locs.xyz'): ValueError: could not convert string to float: **URL:** \ **Category:** Support & Discussions\ **Tags:** eeg, montage\ **Created:** [May 30, 2022, 3:22pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968 "2022-05-30T15:22:28Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 30, 2022, 3:22pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/1 "2022-05-30T15:22:28Z")
- MNE version: 0.23.4 - Ubuntu 18.04.4 ![image](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/d/d7c454183b4c1a51427fad4a5707cec67dc6f324.png) ```python raw_temp = raw.copy() raw_temp.drop_channels(['GSR1', 'GSR2', 'Erg1', 'Erg2', 'Resp', 'Plet', 'Temp']) raw_temp.set_channel_types(mapping={'EXG1': 'eog', 'EXG2': 'eog', 'EXG3': 'eog', 'EXG4': 'eog', 'EXG5': 'eog', 'EXG6': 'eog', 'EXG7': 'eog', 'EXG8': 'eog','Status': 'stim'}) ch_names = raw_temp.ch_names print(raw_temp.info) n_chan = len(ch_names) print(n_chan, '\n', ch_names) # montage = mne.channels.make_standard_montage('biosemi128') montage = mne.channels.read_custom_montage('128+8locs.xyz') raw_temp.set_montage(montage, match_case=False) ``` Hi guys, I am analyzing data from collected with a biosemi 128-channel system + 8 externals and I am struggling to get my montage set up as I want to include my 8 externals in the montage (to include them later down the road into my ICA computation). I have a xyz file (attached here) to describe the location of all my channels but I get an error when using > mne.channels.read\_custom\_montage(‘128+8locs.xyz’) and I get a: > ValueError: could not convert string to float: Could someone help me with that ? ![image](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/4/4e8b05e3fa81c72589029421b0e480fe28185c11.png) Thanks in advance ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 30, 2022, 3:43pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/2 "2022-05-30T15:43:34Z")
Hello @fbarbey ans welcome to the forum! Could you please share the XYZ file? The screenshot is not enough. Thanks! Richard ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 30, 2022, 3:45pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/3 "2022-05-30T15:45:11Z")
Also when you say “externals” — were these sensors actually placed on the head? ---
**Author:** ![JohnAtl](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/johnatl/32/1223_2.png) [@JohnAtl](https://mne.discourse.group/u/JohnAtl)\ **Post date:** [May 31, 2022, 12:27am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/4 "2022-05-31T00:27:39Z")
Have you tried renaming the file and using, say, an underscore instead of the + ? Long shot, but things happen. ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 8:46am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/5 "2022-05-31T08:46:22Z")
Externals mean external channels, sorry for the confusion! These correspond to the EOG channels and the mastoids. ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 8:48am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/6 "2022-05-31T08:48:05Z")
Hi Richard, actually it says I can only attach image file (jpg, png, etc.). I am not really sure of how to share the file ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 8:57am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/7 "2022-05-31T08:57:58Z")
no luck 😕 but good call ! ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 9:02am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/8 "2022-05-31T09:02:32Z")
Actually here you go ```python 1 0 0 1 A1 2 0 -0.19937 0.97992 A2 3 0 -0.39073 0.9205 A3 4 0 -0.56641 0.82413 A4 5 -0.27528 -0.66458 0.69466 A5 6 -0.50865 -0.50865 0.69466 A6 7 -0.59637 -0.59637 0.5373 A7 8 -0.54874 -0.75528 0.35837 A8 9 -0.57972 -0.79792 0.16505 A9 10 -0.58743 -0.80852 -0.034899 A10 11 -0.57154 -0.78666 -0.23345 A11 12 -0.53271 -0.73322 -0.42262 A12 13 -0.28006 -0.86195 -0.42262 A13 14 -0.30048 -0.92478 -0.23345 A14 15 -0.30883 -0.95048 -0.034899 A15 16 -0.30478 -0.93801 0.16505 A16 17 -0.28849 -0.88789 0.35837 A17 18 -0.32275 -0.77919 0.5373 A18 19 0 -0.71934 0.69466 A19 20 0 -0.84339 0.5373 A20 21 0 -0.93358 0.35837 A21 22 0 -0.98629 0.16505 A22 23 0 -0.99939 -0.034899 A23 24 0 -0.97237 -0.23345 A24 25 0 -0.90631 -0.42262 A25 26 0.28006 -0.86195 -0.42262 A26 27 0.30048 -0.92478 -0.23345 A27 28 0.30883 -0.95048 -0.034899 A28 29 0.30478 -0.93801 0.16505 A29 30 0.28849 -0.88789 0.35837 A30 31 0.32275 -0.77919 0.5373 A31 32 0.27528 -0.66458 0.69466 A32 33 0.18961 -0.061608 0.97992 B1 34 0.27629 -0.27629 0.9205 B2 35 0.50865 -0.50865 0.69466 B3 36 0.59637 -0.59637 0.5373 B4 37 0.54874 -0.75528 0.35837 B5 38 0.57972 -0.79792 0.16505 B6 39 0.58743 -0.80852 -0.034899 B7 40 0.57154 -0.78666 -0.23345 B8 41 0.53271 -0.73322 -0.42262 B9 42 0.78666 -0.57154 -0.23345 B10 43 0.80852 -0.58743 -0.034899 B11 44 0.79792 -0.57972 0.16505 B12 45 0.75528 -0.54874 0.35837 B13 46 0.95048 -0.30883 -0.034899 B14 47 0.93801 -0.30478 0.16505 B15 48 0.88789 -0.28849 0.35837 B16 49 0.77919 -0.32275 0.5373 B17 50 0.66458 -0.27528 0.69466 B18 51 0.49052 -0.2832 0.82413 B19 52 0.39073 0 0.9205 B20 53 0.56641 0 0.82413 B21 54 0.71934 0 0.69466 B22 55 0.84339 0 0.5373 B23 56 0.93358 0 0.35837 B24 57 0.98629 0 0.16505 B25 58 0.99939 0 -0.034899 B26 59 0.95048 0.30883 -0.034899 B27 60 0.93801 0.30478 0.16505 B28 61 0.88789 0.28849 0.35837 B29 62 0.77919 0.32275 0.5373 B30 63 0.66458 0.27528 0.69466 B31 64 0.49052 0.2832 0.82413 B32 65 0.11719 0.16129 0.97992 C1 66 0.27629 0.27629 0.9205 C2 67 0.50865 0.50865 0.69466 C3 68 0.59637 0.59637 0.5373 C4 69 0.75528 0.54874 0.35837 C5 70 0.79792 0.57972 0.16505 C6 71 0.80852 0.58743 -0.034899 C7 72 0.58743 0.80852 -0.034899 C8 73 0.57972 0.79792 0.16505 C9 74 0.54874 0.75528 0.35837 C10 75 0.2832 0.49052 0.82413 C11 76 0.27528 0.66458 0.69466 C12 77 0.32275 0.77919 0.5373 C13 78 0.28849 0.88789 0.35837 C14 79 0.30478 0.93801 0.16505 C15 80 0.30883 0.95048 -0.034899 C16 81 0 0.99939 -0.034899 C17 82 0 0.98629 0.16505 C18 83 0 0.93358 0.35837 C19 84 0 0.84339 0.5373 C20 85 0 0.71934 0.69466 C21 86 0 0.56641 0.82413 C22 87 0 0.39073 0.9205 C23 88 -0.2832 0.49052 0.82413 C24 89 -0.27528 0.66458 0.69466 C25 90 -0.32275 0.77919 0.5373 C26 91 -0.28849 0.88789 0.35837 C27 92 -0.30478 0.93801 0.16505 C28 93 -0.30883 0.95048 -0.034899 C29 94 -0.58743 0.80852 -0.034899 C30 95 -0.57972 0.79792 0.16505 C31 96 -0.54874 0.75528 0.35837 C32 97 -0.11719 0.16129 0.97992 D1 98 -0.27629 0.27629 0.9205 D2 99 -0.50865 0.50865 0.69466 D3 100 -0.59637 0.59637 0.5373 D4 101 -0.75528 0.54874 0.35837 D5 102 -0.79792 0.57972 0.16505 D6 103 -0.80852 0.58743 -0.034899 D7 104 -0.95048 0.30883 -0.034899 D8 105 -0.93801 0.30478 0.16505 D9 106 -0.88789 0.28849 0.35837 D10 107 -0.77919 0.32275 0.5373 D11 108 -0.66458 0.27528 0.69466 D12 109 -0.49052 0.2832 0.82413 D13 110 -0.39073 0 0.9205 D14 111 -0.18961 -0.061608 0.97992 D15 112 -0.27629 -0.27629 0.9205 D16 113 -0.49052 -0.2832 0.82413 D17 114 -0.56641 0 0.82413 D18 115 -0.71934 0 0.69466 D19 116 -0.84339 0 0.5373 D20 117 -0.93358 0 0.35837 D21 118 -0.98629 0 0.16505 D22 119 -0.99939 0 -0.034899 D23 120 -0.95048 -0.30883 -0.034899 D24 121 -0.93801 -0.30478 0.16505 D25 122 -0.88789 -0.28849 0.35837 D26 123 -0.77919 -0.32275 0.5373 D27 124 -0.66458 -0.27528 0.69466 D28 125 -0.75528 -0.54874 0.35837 D29 126 -0.79792 -0.57972 0.16505 D30 127 -0.80852 -0.58743 -0.034899 D31 128 -0.78666 -0.57154 -0.23345 D32 129 -0.57219 0.78756 -0.2288 EXG1 130 0.58743 0.80852 -0.2349 EXG2 131 -0.30883 0.95048 -0.4349 EXG3 132 0.30883 0.95048 -0.4349 EXG4 133 -0.97751 -0.15881 -0.13872 EXG5 134 0.95048 -0.15442 -0.1349 EXG6 135 0 0.99939 -0.3349 EXG7 136 0 0 0 EXG8 ``` ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 31, 2022, 9:13am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/9 "2022-05-31T09:13:27Z")
> [@fbarbey](#): > > Externals mean external channels, sorry for the confusion! These correspond to the EOG channels and the mastoids Do you have (measured or template) coordinates for those? If you don’t have sensor locations, then there is no use in trying to force those sensors into the montage. ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 31, 2022, 9:25am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/10 "2022-05-31T09:25:49Z")
Are we talking about those `EXG` sensors in the montage file you shared? 🙂 ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 9:26am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/11 "2022-05-31T09:26:23Z")
yes ! they are included at the end of the files. These are my EOG so I want to include them in my ICA to remove eye movement component from my analyses ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 31, 2022, 9:27am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/12 "2022-05-31T09:27:10Z")
What about EXG8? The coordinates seem to indicate it’s located inside the head? 😅 ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 9:30am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/13 "2022-05-31T09:30:51Z")
good point 😕 that shall be on the opposite side of EXT7, I will correct that ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 10:32am UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/14 "2022-05-31T10:32:55Z")
thanks for that, I corrected the coordinate. However, I am still getting the same error message when trying to set my montage. I am not really sure of what is the problem. ---
**Author:** ![richard](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/richard/32/15_2.png) [@richard](https://mne.discourse.group/u/richard)\ **Post date:** [May 31, 2022, 12:56pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/15 "2022-05-31T12:56:47Z")
The problem is that you have your columns separated by a mixture of spaces and tabs, but MNE-Python expects **tabs only** in XYZ files. So if we fix it like this: ```python 1 0 0 1 A1 2 0 -0.19937 0.97992 A2 3 0 -0.39073 0.9205 A3 4 0 -0.56641 0.82413 A4 5 -0.27528 -0.66458 0.69466 A5 6 -0.50865 -0.50865 0.69466 A6 7 -0.59637 -0.59637 0.5373 A7 8 -0.54874 -0.75528 0.35837 A8 9 -0.57972 -0.79792 0.16505 A9 10 -0.58743 -0.80852 -0.034899 A10 11 -0.57154 -0.78666 -0.23345 A11 12 -0.53271 -0.73322 -0.42262 A12 13 -0.28006 -0.86195 -0.42262 A13 14 -0.30048 -0.92478 -0.23345 A14 15 -0.30883 -0.95048 -0.034899 A15 16 -0.30478 -0.93801 0.16505 A16 17 -0.28849 -0.88789 0.35837 A17 18 -0.32275 -0.77919 0.5373 A18 19 0 -0.71934 0.69466 A19 20 0 -0.84339 0.5373 A20 21 0 -0.93358 0.35837 A21 22 0 -0.98629 0.16505 A22 23 0 -0.99939 -0.034899 A23 24 0 -0.97237 -0.23345 A24 25 0 -0.90631 -0.42262 A25 26 0.28006 -0.86195 -0.42262 A26 27 0.30048 -0.92478 -0.23345 A27 28 0.30883 -0.95048 -0.034899 A28 29 0.30478 -0.93801 0.16505 A29 30 0.28849 -0.88789 0.35837 A30 31 0.32275 -0.77919 0.5373 A31 32 0.27528 -0.66458 0.69466 A32 33 0.18961 -0.061608 0.97992 B1 34 0.27629 -0.27629 0.9205 B2 35 0.50865 -0.50865 0.69466 B3 36 0.59637 -0.59637 0.5373 B4 37 0.54874 -0.75528 0.35837 B5 38 0.57972 -0.79792 0.16505 B6 39 0.58743 -0.80852 -0.034899 B7 40 0.57154 -0.78666 -0.23345 B8 41 0.53271 -0.73322 -0.42262 B9 42 0.78666 -0.57154 -0.23345 B10 43 0.80852 -0.58743 -0.034899 B11 44 0.79792 -0.57972 0.16505 B12 45 0.75528 -0.54874 0.35837 B13 46 0.95048 -0.30883 -0.034899 B14 47 0.93801 -0.30478 0.16505 B15 48 0.88789 -0.28849 0.35837 B16 49 0.77919 -0.32275 0.5373 B17 50 0.66458 -0.27528 0.69466 B18 51 0.49052 -0.2832 0.82413 B19 52 0.39073 0 0.9205 B20 53 0.56641 0 0.82413 B21 54 0.71934 0 0.69466 B22 55 0.84339 0 0.5373 B23 56 0.93358 0 0.35837 B24 57 0.98629 0 0.16505 B25 58 0.99939 0 -0.034899 B26 59 0.95048 0.30883 -0.034899 B27 60 0.93801 0.30478 0.16505 B28 61 0.88789 0.28849 0.35837 B29 62 0.77919 0.32275 0.5373 B30 63 0.66458 0.27528 0.69466 B31 64 0.49052 0.2832 0.82413 B32 65 0.11719 0.16129 0.97992 C1 66 0.27629 0.27629 0.9205 C2 67 0.50865 0.50865 0.69466 C3 68 0.59637 0.59637 0.5373 C4 69 0.75528 0.54874 0.35837 C5 70 0.79792 0.57972 0.16505 C6 71 0.80852 0.58743 -0.034899 C7 72 0.58743 0.80852 -0.034899 C8 73 0.57972 0.79792 0.16505 C9 74 0.54874 0.75528 0.35837 C10 75 0.2832 0.49052 0.82413 C11 76 0.27528 0.66458 0.69466 C12 77 0.32275 0.77919 0.5373 C13 78 0.28849 0.88789 0.35837 C14 79 0.30478 0.93801 0.16505 C15 80 0.30883 0.95048 -0.034899 C16 81 0 0.99939 -0.034899 C17 82 0 0.98629 0.16505 C18 83 0 0.93358 0.35837 C19 84 0 0.84339 0.5373 C20 85 0 0.71934 0.69466 C21 86 0 0.56641 0.82413 C22 87 0 0.39073 0.9205 C23 88 -0.2832 0.49052 0.82413 C24 89 -0.27528 0.66458 0.69466 C25 90 -0.32275 0.77919 0.5373 C26 91 -0.28849 0.88789 0.35837 C27 92 -0.30478 0.93801 0.16505 C28 93 -0.30883 0.95048 -0.034899 C29 94 -0.58743 0.80852 -0.034899 C30 95 -0.57972 0.79792 0.16505 C31 96 -0.54874 0.75528 0.35837 C32 97 -0.11719 0.16129 0.97992 D1 98 -0.27629 0.27629 0.9205 D2 99 -0.50865 0.50865 0.69466 D3 100 -0.59637 0.59637 0.5373 D4 101 -0.75528 0.54874 0.35837 D5 102 -0.79792 0.57972 0.16505 D6 103 -0.80852 0.58743 -0.034899 D7 104 -0.95048 0.30883 -0.034899 D8 105 -0.93801 0.30478 0.16505 D9 106 -0.88789 0.28849 0.35837 D10 107 -0.77919 0.32275 0.5373 D11 108 -0.66458 0.27528 0.69466 D12 109 -0.49052 0.2832 0.82413 D13 110 -0.39073 0 0.9205 D14 111 -0.18961 -0.061608 0.97992 D15 112 -0.27629 -0.27629 0.9205 D16 113 -0.49052 -0.2832 0.82413 D17 114 -0.56641 0 0.82413 D18 115 -0.71934 0 0.69466 D19 116 -0.84339 0 0.5373 D20 117 -0.93358 0 0.35837 D21 118 -0.98629 0 0.16505 D22 119 -0.99939 0 -0.034899 D23 120 -0.95048 -0.30883 -0.034899 D24 121 -0.93801 -0.30478 0.16505 D25 122 -0.88789 -0.28849 0.35837 D26 123 -0.77919 -0.32275 0.5373 D27 124 -0.66458 -0.27528 0.69466 D28 125 -0.75528 -0.54874 0.35837 D29 126 -0.79792 -0.57972 0.16505 D30 127 -0.80852 -0.58743 -0.034899 D31 128 -0.78666 -0.57154 -0.23345 D32 129 -0.57219 0.78756 -0.2288 EXG1 130 0.58743 0.80852 -0.2349 EXG2 131 -0.30883 0.95048 -0.4349 EXG3 132 0.30883 0.95048 -0.4349 EXG4 133 -0.97751 -0.15881 -0.13872 EXG5 134 0.95048 -0.15442 -0.1349 EXG6 135 0 0.99939 -0.3349 EXG7 136 0 0 0 EXG8 ``` we can successfully load and visualize the montage: ```python import mne montage_path = '~/Development/Support/mne-python/montage-xyz/montage_fixed_delim.xyz' montage = mne.channels.read_custom_montage(fname=montage_path) montage.plot() ``` ![output](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/5/599e8781b780f49eda5218bbaaae334f032a127e.png) But you can see that something is off: the head circle is way too small. This is because MNE interprets the values in the XYZ file as coordinates in meters, and the head circle is made for a head with a … well, more natural size. The problem with all these different data formats is that they’re so poorly specified. So while we could try to fix the reader in MNE, I’d suggest to manually import and scale the original data, so you wouldn’t even have to worry about this “mixed tabs and spaces thing” and can work directly with the file you originally shared above. We’ll use pandas to read the data; pandas can readily handle mixed delimiters (which pandas calls “separators”, as it uses the term “delimiters” for a different thing…): ```python import pandas as pd import mne montage_path = '~/Development/Support/mne-python/montage-xyz/montage.xyz' montage_data = pd.read_csv( montage_path, sep='\s+|\t+', # multiple spaces or tabs header=None, names=['ch_idx', 'x', 'y', 'z', 'ch_name'], engine='python' # avoid a warning ) montage_data = montage_data.drop(columns=['ch_idx']) # We don't need it montage_data = montage_data.set_index('ch_name', drop=True) # Now scale based on the head radius (i.e., a value of 1 becomes equal to the head radius) head_radius = 0.095 # in meters montage_data *= head_radius # %% # Prepare for creation of our custom montage – MNE needs the data in the following shape ch_name_to_pos_mapping = montage_data.T.to_dict(orient='list') # Finally, create the montage montage = mne.channels.make_dig_montage( ch_pos=montage_data.T.to_dict(orient='list') # need to get it into the right shape ) montage.plot() ``` ![output](https://global.discourse-cdn.com/free1/uploads/mne/original/2X/4/4eb2daa312c8709f0a552aa4106b8de541287126.png) **Voila!** ---
**Author:** ![fbarbey](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/fbarbey/32/1525_2.png) [@fbarbey](https://mne.discourse.group/u/fbarbey)\ **Post date:** [May 31, 2022, 5:41pm UTC](https://mne.discourse.group/t/mne-channels-read-custom-montage-128-8locs-xyz-valueerror-could-not-convert-string-to-float/4968/16 "2022-05-31T17:41:20Z")
Fantastique. Thanks a lot Richard, I wouldn’t have thought of the space vs. tabulation although now that you point it out, it makes sense haha. Thank you so much