Close

Service Interruption

The NSIDC Web site and data services are currently having intermittent problems and may be unavailable. We are working to restore these services as soon as possible and apologize for any inconvenience this may cause. Please contact NSIDC User Services for assistance.

Summary of MOD10A2/MYD10A2 Bit Values

The Eight Day Snow Cover field in MOD10A2 and MYD10A2 provides a chronology of snow occurrence by associating eight days of snow cover observations with eight separate bits. An introduction to bit processing and interpretation of bit values are provided here.

A single byte consists of eight bits, which is read from right to left. Bit 0 is the least-significant bit, and Bit 7 is the most-significant bit. Bit values are calculated as powers of two. Resulting byte values are calculated by adding the bit values for those bits that are "on".

Summary of bit processing for MOD10A2

So, in the case of the Eight Day Snow Cover field in MOD10A2 and MYD10A2, if snow was present on days one and five (00010001), then the resulting byte value is 17 (1 + 16 = 17). The corresponding grid cell has an integer value of 17.

The following table is provided to interpret the meaning of integer values in the Eight Day Snow Cover field . A number 1 indicates snow for that day, and a 0 indicates no snow for that day.


integer            Day:
 value   8   7   6   5   4   3   2   1
----------------------------------------
   0     0   0   0   0   0   0   0   0
   1     0   0   0   0   0   0   0   1
   2     0   0   0   0   0   0   1   0
   3     0   0   0   0   0   0   1   1
   4     0   0   0   0   0   1   0   0
   5     0   0   0   0   0   1   0   1
   6     0   0   0   0   0   1   1   0
   7     0   0   0   0   0   1   1   1
   8     0   0   0   0   1   0   0   0
   9     0   0   0   0   1   0   0   1
  10     0   0   0   0   1   0   1   0
  11     0   0   0   0   1   0   1   1
  12     0   0   0   0   1   1   0   0
  13     0   0   0   0   1   1   0   1
  14     0   0   0   0   1   1   1   0
  15     0   0   0   0   1   1   1   1
  16     0   0   0   1   0   0   0   0
  17     0   0   0   1   0   0   0   1
  18     0   0   0   1   0   0   1   0
  19     0   0   0   1   0   0   1   1
  20     0   0   0   1   0   1   0   0
  21     0   0   0   1   0   1   0   1
  22     0   0   0   1   0   1   1   0
  23     0   0   0   1   0   1   1   1
  24     0   0   0   1   1   0   0   0
  25     0   0   0   1   1   0   0   1
  26     0   0   0   1   1   0   1   0
  27     0   0   0   1   1   0   1   1
  28     0   0   0   1   1   1   0   0
  29     0   0   0   1   1   1   0   1
  30     0   0   0   1   1   1   1   0
  31     0   0   0   1   1   1   1   1
  32     0   0   1   0   0   0   0   0
  33     0   0   1   0   0   0   0   1
  34     0   0   1   0   0   0   1   0
  35     0   0   1   0   0   0   1   1
  36     0   0   1   0   0   1   0   0
  37     0   0   1   0   0   1   0   1
  38     0   0   1   0   0   1   1   0
  39     0   0   1   0   0   1   1   1
  40     0   0   1   0   1   0   0   0
  41     0   0   1   0   1   0   0   1
  42     0   0   1   0   1   0   1   0
  43     0   0   1   0   1   0   1   1
  44     0   0   1   0   1   1   0   0
  45     0   0   1   0   1   1   0   1
  46     0   0   1   0   1   1   1   0
  47     0   0   1   0   1   1   1   1
  48     0   0   1   1   0   0   0   0
  49     0   0   1   1   0   0   0   1
  50     0   0   1   1   0   0   1   0
  51     0   0   1   1   0   0   1   1
  52     0   0   1   1   0   1   0   0
  53     0   0   1   1   0   1   0   1
  54     0   0   1   1   0   1   1   0
  55     0   0   1   1   0   1   1   1
  56     0   0   1   1   1   0   0   0
  57     0   0   1   1   1   0   0   1
  58     0   0   1   1   1   0   1   0
  59     0   0   1   1   1   0   1   1
  60     0   0   1   1   1   1   0   0
  61     0   0   1   1   1   1   0   1
  62     0   0   1   1   1   1   1   0
  63     0   0   1   1   1   1   1   1
  64     0   1   0   0   0   0   0   0
  65     0   1   0   0   0   0   0   1
  66     0   1   0   0   0   0   1   0
  67     0   1   0   0   0   0   1   1
  68     0   1   0   0   0   1   0   0
  69     0   1   0   0   0   1   0   1
  70     0   1   0   0   0   1   1   0
  71     0   1   0   0   0   1   1   1
  72     0   1   0   0   1   0   0   0
  73     0   1   0   0   1   0   0   1
  74     0   1   0   0   1   0   1   0
  75     0   1   0   0   1   0   1   1
  76     0   1   0   0   1   1   0   0
  77     0   1   0   0   1   1   0   1
  78     0   1   0   0   1   1   1   0
  79     0   1   0   0   1   1   1   1
  80     0   1   0   1   0   0   0   0
  81     0   1   0   1   0   0   0   1
  82     0   1   0   1   0   0   1   0
  83     0   1   0   1   0   0   1   1
  84     0   1   0   1   0   1   0   0
  85     0   1   0   1   0   1   0   1
  86     0   1   0   1   0   1   1   0
  87     0   1   0   1   0   1   1   1
  88     0   1   0   1   1   0   0   0
  89     0   1   0   1   1   0   0   1
  90     0   1   0   1   1   0   1   0
  91     0   1   0   1   1   0   1   1
  92     0   1   0   1   1   1   0   0
  93     0   1   0   1   1   1   0   1
  94     0   1   0   1   1   1   1   0
  95     0   1   0   1   1   1   1   1
  96     0   1   1   0   0   0   0   0
  97     0   1   1   0   0   0   0   1
  98     0   1   1   0   0   0   1   0
  99     0   1   1   0   0   0   1   1
 100     0   1   1   0   0   1   0   0
 101     0   1   1   0   0   1   0   1
 102     0   1   1   0   0   1   1   0
 103     0   1   1   0   0   1   1   1
 104     0   1   1   0   1   0   0   0
 105     0   1   1   0   1   0   0   1
 106     0   1   1   0   1   0   1   0
 107     0   1   1   0   1   0   1   1
 108     0   1   1   0   1   1   0   0
 109     0   1   1   0   1   1   0   1
 110     0   1   1   0   1   1   1   0
 111     0   1   1   0   1   1   1   1
 112     0   1   1   1   0   0   0   0
 113     0   1   1   1   0   0   0   1
 114     0   1   1   1   0   0   1   0
 115     0   1   1   1   0   0   1   1
 116     0   1   1   1   0   1   0   0
 117     0   1   1   1   0   1   0   1
 118     0   1   1   1   0   1   1   0
 119     0   1   1   1   0   1   1   1
 120     0   1   1   1   1   0   0   0
 121     0   1   1   1   1   0   0   1
 122     0   1   1   1   1   0   1   0
 123     0   1   1   1   1   0   1   1
 124     0   1   1   1   1   1   0   0
 125     0   1   1   1   1   1   0   1
 126     0   1   1   1   1   1   1   0
 127     0   1   1   1   1   1   1   1
 128     1   0   0   0   0   0   0   0
 129     1   0   0   0   0   0   0   1
 130     1   0   0   0   0   0   1   0
 131     1   0   0   0   0   0   1   1
 132     1   0   0   0   0   1   0   0
 133     1   0   0   0   0   1   0   1
 134     1   0   0   0   0   1   1   0
 135     1   0   0   0   0   1   1   1
 136     1   0   0   0   1   0   0   0
 137     1   0   0   0   1   0   0   1
 138     1   0   0   0   1   0   1   0
 139     1   0   0   0   1   0   1   1
 140     1   0   0   0   1   1   0   0
 141     1   0   0   0   1   1   0   1
 142     1   0   0   0   1   1   1   0
 143     1   0   0   0   1   1   1   1
 144     1   0   0   1   0   0   0   0
 145     1   0   0   1   0   0   0   1
 146     1   0   0   1   0   0   1   0
 147     1   0   0   1   0   0   1   1
 148     1   0   0   1   0   1   0   0
 149     1   0   0   1   0   1   0   1
 150     1   0   0   1   0   1   1   0
 151     1   0   0   1   0   1   1   1
 152     1   0   0   1   1   0   0   0
 153     1   0   0   1   1   0   0   1
 154     1   0   0   1   1   0   1   0
 155     1   0   0   1   1   0   1   1
 156     1   0   0   1   1   1   0   0
 157     1   0   0   1   1   1   0   1
 158     1   0   0   1   1   1   1   0
 159     1   0   0   1   1   1   1   1
 160     1   0   1   0   0   0   0   0
 161     1   0   1   0   0   0   0   1
 162     1   0   1   0   0   0   1   0
 163     1   0   1   0   0   0   1   1
 164     1   0   1   0   0   1   0   0
 165     1   0   1   0   0   1   0   1
 166     1   0   1   0   0   1   1   0
 167     1   0   1   0   0   1   1   1
 168     1   0   1   0   1   0   0   0
 169     1   0   1   0   1   0   0   1
 170     1   0   1   0   1   0   1   0
 171     1   0   1   0   1   0   1   1
 172     1   0   1   0   1   1   0   0
 173     1   0   1   0   1   1   0   1
 174     1   0   1   0   1   1   1   0
 175     1   0   1   0   1   1   1   1
 176     1   0   1   1   0   0   0   0
 177     1   0   1   1   0   0   0   1
 178     1   0   1   1   0   0   1   0
 179     1   0   1   1   0   0   1   1
 180     1   0   1   1   0   1   0   0
 181     1   0   1   1   0   1   0   1
 182     1   0   1   1   0   1   1   0
 183     1   0   1   1   0   1   1   1
 184     1   0   1   1   1   0   0   0
 185     1   0   1   1   1   0   0   1
 186     1   0   1   1   1   0   1   0
 187     1   0   1   1   1   0   1   1
 188     1   0   1   1   1   1   0   0
 189     1   0   1   1   1   1   0   1
 190     1   0   1   1   1   1   1   0
 191     1   0   1   1   1   1   1   1
 192     1   1   0   0   0   0   0   0
 193     1   1   0   0   0   0   0   1
 194     1   1   0   0   0   0   1   0
 195     1   1   0   0   0   0   1   1
 196     1   1   0   0   0   1   0   0
 197     1   1   0   0   0   1   0   1
 198     1   1   0   0   0   1   1   0
 199     1   1   0   0   0   1   1   1
 200     1   1   0   0   1   0   0   0
 201     1   1   0   0   1   0   0   1
 202     1   1   0   0   1   0   1   0
 203     1   1   0   0   1   0   1   1
 204     1   1   0   0   1   1   0   0
 205     1   1   0   0   1   1   0   1
 206     1   1   0   0   1   1   1   0
 207     1   1   0   0   1   1   1   1
 208     1   1   0   1   0   0   0   0
 209     1   1   0   1   0   0   0   1
 210     1   1   0   1   0   0   1   0
 211     1   1   0   1   0   0   1   1
 212     1   1   0   1   0   1   0   0
 213     1   1   0   1   0   1   0   1
 214     1   1   0   1   0   1   1   0
 215     1   1   0   1   0   1   1   1
 216     1   1   0   1   1   0   0   0
 217     1   1   0   1   1   0   0   1
 218     1   1   0   1   1   0   1   0
 219     1   1   0   1   1   0   1   1
 220     1   1   0   1   1   1   0   0
 221     1   1   0   1   1   1   0   1
 222     1   1   0   1   1   1   1   0
 223     1   1   0   1   1   1   1   1
 224     1   1   1   0   0   0   0   0
 225     1   1   1   0   0   0   0   1
 226     1   1   1   0   0   0   1   0
 227     1   1   1   0   0   0   1   1
 228     1   1   1   0   0   1   0   0
 229     1   1   1   0   0   1   0   1
 230     1   1   1   0   0   1   1   0
 231     1   1   1   0   0   1   1   1
 232     1   1   1   0   1   0   0   0
 233     1   1   1   0   1   0   0   1
 234     1   1   1   0   1   0   1   0
 235     1   1   1   0   1   0   1   1
 236     1   1   1   0   1   1   0   0
 237     1   1   1   0   1   1   0   1
 238     1   1   1   0   1   1   1   0
 239     1   1   1   0   1   1   1   1
 240     1   1   1   1   0   0   0   0
 241     1   1   1   1   0   0   0   1
 242     1   1   1   1   0   0   1   0
 243     1   1   1   1   0   0   1   1
 244     1   1   1   1   0   1   0   0
 245     1   1   1   1   0   1   0   1
 246     1   1   1   1   0   1   1   0
 247     1   1   1   1   0   1   1   1
 248     1   1   1   1   1   0   0   0
 249     1   1   1   1   1   0   0   1
 250     1   1   1   1   1   0   1   0
 251     1   1   1   1   1   0   1   1
 252     1   1   1   1   1   1   0   0
 253     1   1   1   1   1   1   0   1
 254     1   1   1   1   1   1   1   0
 255     1   1   1   1   1   1   1   1