All ChartTiff Topographic Map Tiff files are enhanced to the ChartTiff format with additional tags.
ChartTiff is a superset of the GeoTiff standard.
The following Tiff tags are included.
They are extensions of the Tiff 6.0 specification:
| Tag |
Name |
Description |
| 33550 |
ModelPixelScaleTag |
X, Y and Z pixel scale in map linear units per pixel. |
| 33922 |
ModelTiepointTag |
IJK , XYZ pixel/Coord sets
First 4, SW, NW, NE, SE Define the NEATLINE |
| 34735 |
GeoKeyDirectoryTag |
Geo Key Directory header information |
| 34737 |
GeoAsciiParamsTag |
ASCII Valued keys |
The following GeoTiff keys are included in the GeoKeyDirectory:
| Tag |
Name |
Description |
| 1024 |
GTModelTypeGeoKey |
Coordinate System |
| 1025 |
GTRasterTypeGeoKey |
1 = Raster Pixel Area |
| 3072 |
ProjectedCSTypeGeoKey |
Projected Coordinate System |
| 3073 |
PCSCitationGeoKey |
ASCII reference to published documentation |
| 4099 |
VerticalUnitsGeoKey |
Vertical Datum Units—Feet or Meters |
The following ChartTiff keys have been added to the GeoKeyDirectory:
| Tag |
Name |
Description |
| 47002 |
ChartSource |
Source of the map ie. USGS |
| 47004 |
ChartSourceDate |
Source date of map data |
| 47005 |
ChartCorrDate |
Last Revision Date of map |
| 47017 |
ChartContourInterval |
Contour interval Multiplied by 10,
see VerticalUnitsGeoKey for units |
|
