File: DRG_NAME.TXT Date: October 5, 1995 *************************************************************************** STANDARDIZED DATA SET NAMES FOR DRG PRODUCTS To facilitate file manipulation by the widest possible range of potential users, data and text files on this CD-ROM conform to the DOS "eight plus three" (8.3) file naming convention. The associated DRG image (.TIF), world (.TFW), and metadata (.FGD) files on this disc incorporate an intelligent data set name (DSN) consisting of descriptive metadata wrapped around a standardized kernel that describes the spatial location of the file. The intent of this file naming protocol is to positively identify the spatial identity of the file and describe its categoric identity. The DSN is designed to geographically locate DRG's of quadrangles using the 7.5-minute grid, clearly identifying those that fall exactly on the grid. DRG's that are not aligned with the 7.5-minute grid can be named with this convention but additional consideration is required to relate these undersize, oversize, or offset quadrangles to their most logical and unique 7.5-minute grid location. For additional information about the DSN convention applied to DRG's, refer to MAPINDEX.TXT in the \DOCUMENT directory. *************************************************************************** DSN CONVENTION APPLIED TO DRG PRODUCTS CATEGORY + LAT/LONG OF SECONDARY CELL + MAP INDEX NUMBER + --------- -------------------------- ----------------------- One Alpha Five Numeric One Alpha + One Numeric (A) (YYXXX) (A) (N) PERIOD OPERAND + FILE TYPE --------- Three Alpha (TIF) AYYXXXAN.TIF Where: A = Category (Series, Scale, and Class) YY = Degrees Latitude (Secondary Cell) XXX = Degrees Longitude (Secondary Cell) AN = Map Index Number (Primary Cell) TIF = Tagged Image File Format EXAMPLE: O37091H7.TIF = Rolla, Missouri, 7.5-minute, 1:24,000-scale Topographic Quadrangle Where: O = 7.5-minute, 1:24,000-scale Topographic Quadrangle 37 = Degrees Latitude 091 = Degrees Longitude H7 = Map Index Number for the Rolla Quadrangle TIF = Tagged Image File Format *************************************************************************** DEFINITIONS: CATEGORY - One alpha character identifying the series, scale, and class of the DRG. --------------------------------------------------------- CATEGORY SERIES SCALE CLASS --------------------------------------------------------- R 7.5' 1:20,000 Topographic O 7.5' 1:24,000 Topographic P 7.5' 1:24,000 Orthophoto L 7.5' 1:25,000 Topographic J 7.5' 1:30,000 Topographic K 7.5'X15' 1:25,000 Topographic I Alaska 1:63,360 Topographic G 30'x60' 1:100,000 Planimetric F 30'x60' 1:100,000 Topographic C 1 x 2 Degree 1:250,000 Topographic --------------------------------------------------------- LAT/LONG OF SECONDARY CELL - Expressed in degrees of latitude (2 characters) and degrees of longitude (3 characters), defining the southeast corner (integer grid corner), of the secondary cell. To maintain unique DSN's throughout this series, the longitude of secondary cells falling in the eastern hemisphere, west of 180-degrees, are incremented upward from 180. As an example, the southeast corner of a 1-degree secondary cell located at 52-degrees north latitude and 175-degrees east longitude (5 degrees west of 180) converts to the following five-character code describing the cell's location: 52185. SECONDARY CELL - 1- by 1-degree cell (except Alaska) defined by integer latitude and longitude. Cells in Alaska vary in size, but are always identified by integer latitude and longitude. MAP INDEX NUMBER - Two-character alphanumeric code locating the primary cell (quadrangle) within the secondary cell. TIF - Tagged Image File Format (TIFF) - A tag based file format that is designed to promote the interchange of digital image data. *************************************************************************** The following examples of Data Set Names for the DRG products contained on this disc are not all inclusive. Normal packaging of one 1:250,000-scale, two 1:100,000-scale, and sixty-four 1:24,000-scale quadrangles can involve combining several categories of maps on each disc. For example, to complete a 1- by 1-degree coverage area, it is entirely possible that a single distributable DRG CD-ROM can contain one or more of the following map categories: 1:24,000- and 1:25,000-scale, 7.5-minute quadrangles. 1:24,000-scale 7.5-minute Provisional Maps. 1:24,000-scale 7.5-minute Orthophotomaps. 1:25,000-scale 7.5- by 15-minute quadrangles. As a result, optimal packaging of sixty-four 7.5-minute quadrangles is compromised if one or more 7.5- by 15-minute quads are included in a 1-by 1-degree cell. *************************************************************************** DATA SET NAMES For 7.5- by 7.5-Minute Series 1:24,000- And 1:25,000-Scale Data 41089 090 089 42 +-----+-----+-----+-----+-----+-----+-----+-----+ 42 | | | | | | | | | | | | | | | | | | H | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | +--->| | | | | | | | | G | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | F | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | E | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | D | | | | | | | | | |<---+ | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | | | C | | | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | | | B | | | | | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | | | | | A | | | | | | | | | | | | | 41 +-----+-----+-----+-----+-----+-----+-----+-----+ 41 | | 090 8 7 6 5 4 ^ 3 2 1 089 | | | | | 41089A4 - Identifies--+ | | 41089D1 - Identifies--------------------------+ | 41089G8 - Identifies--+ | | +---------------------------------+ ----------------------------------------------- Quadrangle Full data set name ----------------------------------------------- 41089A4 = Lacon, IL. O41089A4.TIF 41089D1 = Troy Grove, IL. O41089D1.TIF 41089G8 = Morrison, IL. +--O41089G8.TIF | Where: O = 7.5-minute, 1:24,000-scale Topographic Quadrangle 41 = Degrees Latitude 089 = Degrees Longitude G8 = Map Index Number for the Morrison Quadrangle TIF = Tagged Image File Format ************************************************************************** In the following example, the DSN identifies 7.5- by 15-minute primary cells (quadrangles). Dotted vertical lines indicate the normal 7.5- by 7.5- minute grid spacing. As in the previous example, rows A through H and columns 1 through 8 are used to determine the Map Index Number. In this case, however, identification of the 7.5- by 15-minute primary cell is based solely on columns 1, 3, 5, and 7. ************************************************************************** DATA SET NAMES For 7.5- by 15-Minute Series 1:25,000-Scale Data 42071 072 071 43 +-----------+-----------+-----------+-----------+ 43 | : | : | : | : | H | : | : | : | : | | : | : | : | : | +-----------+-----------+-----------+-----------+ | : | : | : | : | G | : | : | : | : | | : | : | : | : | +-----------+-----------+-----------+-----------+ | : | : | : | : | F | Ashburnham| : | : | : | +--->| : | : | : | : | | +-----------+-----------+-----------+-----------+ | | : | : | : | : | | E | : | : | : | : | | | : | : | : | : | | +-----------+-----------+-----------+-----------+ | | : | : | : | : | | D | : | : | : | Boston |<---+ | | : | : | : | North | | | +-----------+-----------+-----------+-----------+ | | | : | : | : | : | | | C | : | : | : | : | | | | : | : | : | : | | | +-----------+-----------+-----------+-----------+ | | | : | : | : | : | | | B | : | : | : | : | | | | : | : | : | : | | | +-----------+-----------+-----------+-----------+ | | | : | : | : | : | | | A | : | : | Franklin | : | | | | : | : | : | : | | | 42 +-----------+-----------+-----------+-----------+ 42 | | 072 (8) 7 (6) 5 (4) ^ 3 (2) 1 071 | | | | | 42071A3 - Identifies---+ | | 42071D1 - Identifies--------------------------+ | 42071F7 - Identifies---+ | | +----------------------------------+ -------------------------------------------------- Quadrangle Full data set name -------------------------------------------------- 42071A3 = Franklin, MA K42071A3.TIF 42071D1 = Boston North, MA K42071D1.TIF 42071F7 = Ashburnham, MA +----K42071F7.TIF | Where: K = 7.5- by 15-minute, 1:25,000-scale Topographic Quadrangle 42 = Degrees Latitude 071 = Degrees Longitude F7 = Map Index Number for the Ashburnham Quadrangle TIF = Tagged Image File Format ************************************************************************** In the example below, the Fairbanks 1:250,000-scale quadrangle comprises three 1- by 1-degree secondary cells. Dashed grids represent 15- by 30- minute, 1:63,360-scale quadrangles. Dotted lines represent 7.5- by 7.5- minute subdivisions of sixty-four 7.5-minute cells comprising the 1-degree cell. These cells are the primary identifiers of the map locations based on the position of the 7.5-minute cell nearest the southeast corner of each 1:63,360-scale quadrangle. *************************************************************************** DATA SET NAMES For Alaska 1:63,360-Scale Data FAIRBANKS (1:250,000) 150 149 148 147 7 5 3 1 7 5 3 1 7 5 3 1 65 +-------+-------+-------+-------+-------+-------+ 65 | : : : | : : : | : : : | : : : | : : : | : : : | H | : : : | : : : | : : : | : : : | : : : | : : : | H +--->|.:.D6:.|.:.D5:.|.:.D4:.|.:.D3:.|.:.D2:.|.:.D1:.| | | : : : | : : : | : : : | : : : | : : : | : : : | | G | : : : | : : : | : : : | : : : | : : : | : : : | G | +-------+-------+-------+-------+-------+-------+ | | : : : | : : : | : : : | : : : | : : : | : : : | | F | : : : | : : : | : : : | : : : | : : : | : : : | F | |.:.C6:.|.:.C5:.|.:.C4:.|.:.C3:.|.:.C2:.|.:.C1:.|<---+ | | : : : | : : : | : : : | : : : | : : : | : : : | | | E | : : : | : : : | : : : | : : : | : : : | : : : | E | | +-------+-------+-------+-------+-------+-------+ | | | : : : | : : : | : : : | : : : | : : : | : : : | | | D | : : : | : : : | : : : | : : : | : : : | : : : | D | | |.:.B6:.|.:.B5:.|.:.B4:.|.:.B3:.|.:.B2:.|.:.B1:.| | | | : : : | : : : | : : : | : : : | : : : | : : : | | | C | : : : | : : : | : : : | : : : | : : : | : : : | C | | +-------+-------+-------+-------+-------+-------+ | | | : : : | : : : | : : : | : : : | : : : | : : : | | | B | : : : | : : : | : : : | : : : | : : : | : : : | B | | |.:.A6:.|.:.A5:.|.:.A4:.|.:.A3:.|.:.A2:.|.:.A1:.| | | | : : : | : : : | : : : | : : : | : : : | : : : | | | A | : : : | : : : | : : : | : : : | : : : | : : : | A | | 64 +-------+-------+-------+-------+-------+-------+ 64 | | 7 5 3 1 7 5 3 ^ 1 7 5 3 1 | | 150 149 | 148 147 | | | | | 64148A1 - Identifies-+ | | 64147E1 - Identifies-------------------------+ | 64149G5 - Identifies-+ | | +---------------------------------+ ---------------------------------------------- Quadrangle Full data set name ---------------------------------------------- 64148A1 = Fairbanks (A3) I64148A1.TIF 64147E1 = Fairbanks (C1) I64147E1.TIF 64149G5 = Fairbanks (D6) +---I64149G5.TIF | Where: I = Alaska, 1:63,360-scale Topographic Quadrangle 64 = Degrees Latitude 147 = Degrees Longitude G5 = Map Index Number for the Fairbanks (D6) Quadrangle TIF = Tagged Image File Format ************************************************************************** DATA SET NAMES For 30- by 60-Minute Series 1:100,000-Scale Data 091 090 39 +-------------------------------+ 39 | | | | | | | 38090-E1 | +---->| ST LOUIS | | | | | | | | | | | | | | +-------------------------------+ | | | | | | | | | | | 38090-A1 | | | FESTUS |<----+ | | | | | | | | | | | | | | | | | 38 +-------------------------------+ 38 | | 091 090 | | | | 38090A1 - Identifies----------------+ | 38090E1 - Identifies--+ | | +-----------------------------+ ---------------------------------------------------- Quadrangle Full data set name ---------------------------------------------------- 38090A1 = Festus, MO. F38090A1.TIF 38090E1 = St. Louis, MO. +---F38090E1.TIF | Where: F = 1:100,000-scale, 30- by 60-minute Topographic Quadrangle 38 = Degrees Latitude 090 = Degrees Longitude E1 = Map Index Number for the St. Louis Quadrangle TIF = Tagged Image File Format ************************************************************************** In the following example, the dotted vertical line represents the division between the east and west 1-degree secondary cells of the 1:250,000-scale quadrangle for illustrative purposes only. *************************************************************************** DATA SET NAMES For 1- by 2-Degree Series 1:250,000-Scale Data 094 093 092 39 +----------------------------------+ 39 | : | | : | | : | | : | | 38092-A1 | | JEFFERSON CITY |<----+ | : | | | : | | | : | | | : | | | : | | 38 +----------------------------------+ 38 | 094 093 092 | | 38092A1 - Identifies-------------------+ -------------------------------------------------- Quadrangle Full data set name -------------------------------------------------- 38092A1 = Jefferson City +---C38092A1.TIF | Where: C = 1:250,000-scale, 1- by 2-degree Topographic Quadrangle 38 = Degrees Latitude 092 = Degrees Longitude A1 = Map Index Number for the Jefferson City Quadrangle TIF = Tagged Image File Format ************************************************************************** The following two examples describe cases where the products to be named do not conform to the normal grid. The examples illustrate the process of naming quads that are undersized, oversized, or off-set in relationship to the regular 7.5-minute grid. ************************************************************************* Example 1 DATA SET NAMES For The Pacific Islands (Guam) Shifted Undersize Quads 1:24,000-Scale Data 13145 144 145 14 +------+------+------+------+------+------+------+------+ 14 | | | | | | | | | | | | | | | | | | H | | | | | | | | | +------+------+------+------+------+------+------+------+ | | | | | | | | | | | | | | | | | | G | | | | | | | | | +------+------+------+------+------+------+------+------+ | | | | | | | | | | | | | | | | | | F | | | | | | | ....... | +------+------+------+------+------+------+--: :....+ | | | | | | | : A : : | | | | | | | : : B : E | | | | | ............:.....: : +------+------+------+------+----: : : :....+ | | | | | : C : D : E : | | | | | | : : : : | D | | | | | :.....:.....:.....: | +------+------+------+------+----: : :---+------+ | | | | | : F : G : | | | | | | | : : : | | C | | | | | :.....:.....: | | +------+------+------+------+----: : :---+------+ | | | | | : H : J : | | | | | | | : : : | | B | | | | | :.....:.....: | | +------+------+------+------+------+------+------+------+ | | | | | | | | | | | | | | | | | | A | | | | | | | | | 13 +------+------+------+------+------+------+------+------+ 13 144 8 7 6 5 4 3 2 1 145 Dashed grids represent the normal 7.5- by 7.5-minute quadrangles (primary cells) comprising the 1- by 1-degree secondary cell. Dotted grids represent undersize USGS quadrangles that have been shifted from the normal 7.5- by 7.5-minute configuration to cover land. Uppercase letters (A-J) within each dotted grid represent individual quadrangles. ----------------------------------------------------------- Quad name Secondary cell and series number ----------------------------------------------------------- Inarajan (J) 13145B2 Merizo (H) 13145B3 Talofofo (G) 13145C2 Agat (F) 13145C3 Dededo (E) 13145D1 Agana (D) 13145D2 Apra Harbor (C) 13145D3 Pati Point (B) 13145E1 Retidian Point (A) 13145E2 ------------------------------------------------------------------ Full data set names for the above examples: Inarajan............................O13145B2.TIF Merizo..............................O13145B3.TIF Talofofo............................O13145C2.TIF Agat................................O13145C3.TIF Dededo..............................O13145D1.TIF Agana...............................O13145D2.TIF Apra Harbor.........................O13145D3.TIF Pati Point..........................O13145E1.TIF Retidian Point......................O13145E2.TIF | | Where: O = 1:24,000-scale Topographic Quadrangle 13 = Degrees Latitude 145 = Degrees Longitude E2 = Map Index Number for the Retidian Point Quadrangle TIF = Tagged Image File Format Example 1 illustrates the hierarchy for determining cells and series numbers for quadrangles that are not aligned with the 7.5-minute grid (undersized/offset). Quads C, D, E, F, G, H, and J assume the series number assigned to the primary cell in which their southeast corner lies. The position of the southeast corner, or nearest southeast cell corner, is the PRINCIPAL determinant of series number within the secondary cell. However, the southeast corners of quads A and B fall in primary cell E1 so the NEXT determining factor is the percentage of area in the quadrangles bounded by this cell. In this case all of quad B is bound by primary cell E1, while a relatively small portion of quad A is bounded by the E1 cell. As a result, quadrangle B is assigned to the E1 cell. Quadrangle A is assigned to the primary cell associated with the cell bounding the most area within the quad, not having already been assigned to another quad. In this case quadrangle A is assigned to cell E2. To properly determine the series number, for this case, all the surrounding quads must be considered. ************************************************************************** Example 2 DATA SET NAMES For The Pacific Islands (Pohnpei Islands) Overedge, Oversize And Shifted Quads 1:25,000-Scale Data 158 159 +---................----+-----+-----+-----+-----+ 07201 | : : | | | | | 07201 ----- 07 +===: A :====+=====+=====+=====+=====+ 07 ----- 06201 | : : | | | | | 06201 | :..............: | | | | | H | : : | | | | | +---: B :----+-----+-----+-----+-----+ | : : | | | | | | :..............: | | | | | G | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | F | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | E | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | D | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | C | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | B | | | | | | | | | +-----+-----+-----+-----+-----+-----+-----+-----+ | | | | | | | | | | | | | | | | | | A | | | | | | | | | 06 +-----+-----+-----+-----+-----+-----+-----+-----+ 06 158 8 7 6 5 4 3 2 1 159 Dashed grids represent the normal 7.5- by 7.5-minute quadrangles (primary cells) comprising the 1- by 1-degree secondary cell. This particular secondary cell is extended to the north above 7 degrees latitude to include the Pohnpei North (H5) oversize quadrangle. Dotted grids represent oversize USGS quadrangles that have been shifted from the normal 7.5- by 7.5-minute configuration to cover land. Uppercase letters A and B within each dotted grid represent individual quadrangles. ------------------------------------------------------------- Quad name Secondary cell and series number ------------------------------------------------------------- Pohnpei South (B) L06159G5 Pohnpei North (A) L06159H5 -------------------------------------------------------------- Full data set names for the above examples: Pohnpei South (B)................L06159G5.TIF Pohnpei North (A)................L06159H5.TIF | | Where: L = 1:25,000-scale Topographic Quadrangle 06 = Degrees Latitude 159 = Degrees Longitude H5 = Map Index Number for the Pohnpei North Quadrangle TIF = Tagged Image File Format Example 2 illustrates possible overedge quad configurations that often occur in island areas. Graphics are shifted and adjusted in size to minimize the number of map sheets required to effect coverage of island land masses. Cases such as these can be solved as illustrated for proper data set name identification. If the quad has an overedge that is adjacent to the southeast corner of the cell, the normal southeast corner coordinates of the 7.5-minute grid intersection is used for DSN determination. *************************************************************************