Hi Anita,
Your population map has some weird, non-text encoding. If I look at the encoding I see the following:
% head copperpopmap.txt
??CO0001_minq20_sorted WC
CO0002_minq20_sorted WC
CO0003_minq20_sorted WC
CO0004_minq20_sorted NPS
CO0005_minq20_sorted WC
CO0006_minq20_sorted WC
CO0007_minq20_sorted WC
CO0008_minq20_sorted WC
CO0009_minq20_sorted WC
CO0010_minq20_sorted NPS
% head copperpopmap.txt | od -c
0000000 377 376 C \0 O \0 0 \0 0 \0 0 \0 1 \0 _ \0
0000020 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0 s \0
0000040 o \0 r \0 t \0 e \0 d \0 \t \0 W \0 C \0
0000060 \n \0 C \0 O \0 0 \0 0 \0 0 \0 2 \0 _ \0
0000100 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0 s \0
0000120 o \0 r \0 t \0 e \0 d \0 \t \0 W \0 C \0
0000140 \n \0 C \0 O \0 0 \0 0 \0 0 \0 3 \0 _ \0
0000160 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0 s \0
0000200 o \0 r \0 t \0 e \0 d \0 \t \0 W \0 C \0
0000220 \n \0 C \0 O \0 0 \0 0 \0 0 \0 4 \0 _ \0
0000240 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0 s \0
0000260 o \0 r \0 t \0 e \0 d \0 \t \0 N \0 P \0
0000300 S \0 \n \0 C \0 O \0 0 \0 0 \0 0 \0 5 \0
0000320 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000340 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 W \0
0000360 C \0 \n \0 C \0 O \0 0 \0 0 \0 0 \0 6 \0
0000400 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000420 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 W \0
0000440 C \0 \n \0 C \0 O \0 0 \0 0 \0 0 \0 7 \0
0000460 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000500 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 W \0
0000520 C \0 \n \0 C \0 O \0 0 \0 0 \0 0 \0 8 \0
0000540 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000560 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 W \0
0000600 C \0 \n \0 C \0 O \0 0 \0 0 \0 0 \0 9 \0
0000620 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000640 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 W \0
0000660 C \0 \n \0 C \0 O \0 0 \0 0 \0 1 \0 0 \0
0000700 _ \0 m \0 i \0 n \0 q \0 2 \0 0 \0 _ \0
0000720 s \0 o \0 r \0 t \0 e \0 d \0 \t \0 N \0
0000740 P \0 S \0 \n
0000745
Octal dump (od -c) displays the numerical encoding of the text and this file is not plain text. Note the file starts with characters 377 and 376, which do not have a text encoding, and then all the embedded NULL characters (“\0”). I assume this is some kind of Unicode encoding that you saved from a word processor or similar. Remake the file with a plain text editor or on the UNIX command line, say using the nano program.
Best,
julian