This feature class represents the 16 latitude/longitude tics on a 1:24,000-scale 7.5 minute quadrangle. Tics are spaced every 2' 30" (2.5 minutes) within and around the extent of the quadrangle. The tics are useful when georeferencing raster datasets to the quadrangle.
Tics can be generated using an Excel spreadsheet by entering the coordinate for the NW corner of the quadrangle. One addtional tic may be present at the center of the map, tic = 0, that does not appear on USGS quadrangles. The coordinates for the center of the map are useful for determining the current magnetic declination for the quadrangle using NOAA's declination calculator.
| Field Name | Field Alias | Length (text fields) |
Field Type | Field Value | Default | Allow Nulls? | Attributes / Examples | Description / Notes |
|---|---|---|---|---|---|---|---|---|
| tic | Tic_ID | Long Integer | variable | [null] | TRUE | 11, 12, 13, 14, 21, 22, 23, etc (left-to-right column/ top-to-bottom row pairs) or 0 for the location of the center of the map. |
The coordinates for the center of the map are useful for determining the current magnetic declination. | |
| long_dd | Longitude_dd | Double | variable | [null] | TRUE | -106.000000000 | Longitude in decimal degrees (negative for west longitude). | |
| lat_dd | Latitude_dd | Double | variable | [null] | TRUE | 35.750000000 |
Latitude in decimal degrees. |