ChartTiff's Original Collarless / Seamless Geo's are generated from Scanned USGS DRGs, collared Topographic Maps.

• Totally Collarless and Seamless Topographic Maps.


• No Setting Clipping or Setting a Transparency Layer required.
  Plug compatible with your GIS System.


• Complete Coverage of the US including Alaska and Hawaii


• Includes all 1:24,000, 1:100,000 and 1:250,000 scale files


• 250 DPI resolution, 256 color palette


• Available Projections (selected during check-out)
  • UTM - User Selectable Zones - NAD27 / NAD83 / WGS72 / WGS84
  • State Plane - User Selectable Zones - NAD27 / NAD83
  • Latitude / Longitude - NAD27 / NAD83 / WGS72 / WGS84
  • Web Mercator - WGS84


• Standard GeoTiff format enhanced with ChartTiff Extensions
  Plus ESRI "tfw" and MapInfo "tab" files.


• Optional JPEG format.  Selectable at Check-Out.


• Add Shaded Relief to NextGen Geo Topographic Maps.
  

  Click here for details

ChartTiff's Original Collared NextGen DRG's are generated from Scanned USGS DRGs, collared Topographic Maps.

• Collared Topographic Maps.


• Complete Coverage of the US including Alaska and Hawaii


• Includes all 1:24,000, 1:100,000 and 1:250,000 scale files


• 250 DPI resolution, 256 color palette


• Available Projections (selected during check-out)
  • UTM - User Selectable Zones - NAD27 / NAD83 / WGS72 / WGS84
  • State Plane - User Selectable Zones - NAD27 / NAD83
  • Latitude / Longitude - NAD27 / NAD83 / WGS72 / WGS84
  • Web Mercator - WGS84


• Standard GeoTiff format enhanced with ChartTiff Extensions
  Plus ESRI "tfw" and MapInfo "tab" files.


• Optional JPEG format.  Selectable at Check-Out.


• Add ChartTiff Enhanced DRG Collars.
  

  Click here for details

• Add Shaded Relief to NextGen Geo Topographic Maps.
  

  Click here for details

• A ChartTiff Original Geo map is created from the original USGS DRG topographic maps.
  
  The quad is first projected to your requested projection,  then cropped to the map extents.  The voided areas of the map are then filled with the necessary adjacent map information to make the map and tiff file rectangular.

• All ChartTiff Geo raster images are geometrically registered at the pixel level from map to map.
  
  All ChartTiff Geo raster images allow for easy panning from one map to another, without worrying about map overlap and transparency problems associated with other map products.

• The Tiff files are then enhanced to the ChartTiff format with additional tags. ChartTiff is a superset of the GeoTiff standard.
  • View ChartTiff standard in a PDF format.
  • View tag extensions used in ChartTiffs.
  • View GeoTiff standard in a PDF format.
  • View Tiff 6.0 standard in a PDF format.

QUAD Naming Convention

Quad name format was developed by the USGS and is used to specify the geographic location of a quad map in latitude / longitude coordinates. For example, for quad name O34119d6, the letter "O" specifies the map scale 1:24,000. The number 34 specifies base latitude of 34 degrees, and the number 119 specifies base longitude of 119 degrees.

Each 1:24,000 map location is 7.5 minutes by 7.5 minutes; which equates to 8 x 8 = 64 quad locations in a 1 degree by 1 degree square of geographical area. The 8 rows and 8 columns of quad locations within each square degree are designated by the last
2 letters of the quad name. In this example (O34119d6), the quad is the fourth row (the letter 'd'), and sixth column (the digit '6').  Rows are designated from 'a' (south-most) to 'h' (north-most), and columns are designated from '1' (east-most) to '8' (west-most). The 64 quad locations for the example are:

The following table lists the partial degree values for the bottom (south) edge of each quad location:

The following table list the partial degree values for the right (east) edge of each quad location:

For a more detailed description of quad name standards, see:
"USGS DRG Naming Convention"