10-02-98 This directory contains the 1:100,000-scale Digital Line Graph (DLG) data. *** File transfer mode must be set to BINARY if your Web browser *** *** doesn't do this automatically. *** *** The data files are stored on a robotic mass-storage device so there *** *** may be a short (~10 seconds) delay while the media is retrieved. *** *** If you have any questions or suggestions, please contact Customer *** *** Services at custserv@edcmail.cr.usgs.gov *** DIRECTORY STRUCTURE: The directory structure for the 1:100,000-Scale DLG FTP account is defined as follows: A-Z/mapname-e_STATE/layer where: A-Z = The first character of the map name mapname = The name of the 1:100,000-scale map e = The east or west half of the map (30- x 30-minute area) STATE = The two character state code used to distinguish between duplicate map names layer = The category of data (such as hydrography or transportation) Example: H/harrison-e_AR/transportation is the location for all transportation layers in the east half of the Harrison, Arkansas quadrangle. This directory contains the 1:100,000-scale Digital Line Graph (DLG) data, offered in two formats, Optional and Spatial Data Transfer Standard (SDTS). This file pertains to the SDTS format only. To obtain more information about DLG optional format please refer to the "00README" file stored under the data/DlG/100K ftp account. If you select the SDTS format you need only download one file ex:(*.hydro.sdts.tar.gz) to obtain the 30-minute coverage. However, you will also need to download the Master Data Dictionary (MDD), "00MASTERDD_100K.SDTS" - Version 1.0, which is meant to be used in conjunction with a 100K (DLG-3) SDTS transfer to form a fully compliant SDTS/Topological Vector Profile (TVP) transfer. The MDD may be found in this directory as a compressed tar file, (00MASTERDD_100K.SDTS.tar.gz), or as separate uncompressed files in the 00MASTERDD_100K.SDTS directory. Please refer to the "README" file found at /data/DLG/100K/00MASTERDD_100K.SDTS for more MDD information. ***** PLEASE NOTE THAT YOU MUST HAVE THE MASTER DATA ***** DICTIONARY AT THE SAME DIRECTORY LEVEL AS THE DATA. FILE EXTENT: SDTS transfers are stored as compressed "tar" archive files. Each transfer contains a complete set of files, for a specific layer, covering a 30-minute area. The transfer naming convention is as follows: XXX.layer.sdts.tar.gz. XXX = unique quadrangle identifier layer = data category name (such as hydro for hydrography or trans for transportation) sdts = denotes that the data is in SDTS format tar = represents "tar" file gz = refers to the "gzip" compression The "tar" files have been compressed to speed up the download. You will need to decompress the ".gz" files before untarring the SDTS files. For more information on how to first unzip, then untar the downloaded files, see the FILE COMPRESSION section of this readme. Unzipping and untarring SDTS data creates several files all having a .DDF extension. Refer to "DLG-3 SDTS Transfer Description" draft document for details about the SDTS format. It may be found at at the SDTS information ftp site in two formats. Word Perfect - ftp://sdts.er.usgs.gov/pub/sdts/datasets/tvp/dlg3/dlg3.wp Post Script - ftp://sdts.er.usgs.gov/pub/sdts/datasets/tvp/dlg3/dlg3.ps TILE NUMBERING SCHEME: Each 30-minute area consists of a varying number of DLG files depending on the layer and the feature density. If the feature density in an area is such that the file size exceeded the limitations of the processing programs, that 30-minute area is covered by sixteen 7.5-minute files. This occurs in the Hydrography or Hypsography transfer and also in the Roads and Transportation transfer. The SDTS tile numbering scheme is slightly different from the one used in the Optional 100K DLG package. (For more information about it refer to the "00README" file stored in the data/DLG/100K directory at this ftp site.) The normal SDTS tile numbering scheme looks like this for all layers except Transportation: (normal) west east --------------------------------------------------------------- | | | | | | 01 | 02 | 01 | 02 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 03 | 04 | 03 | 04 | | | | | | --------------------------------------------------------------- A 1:100,000-scale quad, in SDTS format, divided into eight 15-minute quads, 4 per 30-minute area. A dense SDTS transfer looks like this for all transfers except Transportation: (dense) west east --------------------------------------------------------------- | | | | | | | | | | 01 | 02 | 03 | 04 | 01 | 02 | 03 | 04 | | | | | | | | | | --------------------------------------------------------------- | 05 | 06 | 07 | 08 | 05 | 06 | 07 | 08 | | | | | | | | | | --------------------------------------------------------------- | 09 | 10 | 11 | 12 | 09 | 10 | 11 | 12 | | | | | | | | | | --------------------------------------------------------------- | 13 | 14 | 15 | 16 | 13 | 14 | 15 | 16 | | | | | | | | | | --------------------------------------------------------------- A 1:100,000-scale quad, in SDTS format, divided into 32 7.5-minute quads, 16 per 30-minute area. PLEASE NOTE: The Transportation transfer is made up of three categories which include 1)Miscellaneous Transportation, 2)Roads and Trails, and 3)Railroads. A Transportation transfer with a normal Roads and Trails layer would be numbered as displayed below: Pipelines, etc. (numbered 1-4 per east or west half) (normal) west east --------------------------------------------------------------- | | | | | | 01 | 02 | 01 | 02 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 03 | 04 | 03 | 04 | | | | | | --------------------------------------------------------------- Roads and Trails (numbered 5-8 per east or west half) (normal) west east --------------------------------------------------------------- | | | | | | 05 | 06 | 05 | 06 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 07 | 08 | 07 | 08 | | | | | | --------------------------------------------------------------- Railroads (numbered 9-12 per east or west half) (normal) west east --------------------------------------------------------------- | | | | | | 09 | 10 | 09 | 10 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 11 | 12 | 11 | 12 | | | | | | --------------------------------------------------------------- A dense Transportation transfer would be numbered as displayed below: Pipelines, etc. (numbered 1-4 per east or west half) (dense) west east --------------------------------------------------------------- | | | | | | 01 | 02 | 01 | 02 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 03 | 04 | 03 | 04 | | | | | | --------------------------------------------------------------- Roads and Trails (numbered 5-20 per east or west half) (dense) west east --------------------------------------------------------------- | 05 | 06 | 07 | 08 | 05 | 06 | 07 | 08 | | | | | | | | | | --------------------------------------------------------------- | 09 | 10 | 11 | 12 | 09 | 10 | 11 | 12 | | | | | | | | | | --------------------------------------------------------------- | 13 | 14 | 15 | 16 | 13 | 14 | 15 | 16 | | | | | | | | | | --------------------------------------------------------------- | 17 | 18 | 19 | 20 | 17 | 18 | 19 | 20 | | | | | | | | | | --------------------------------------------------------------- Railroads (numbered 21-24 per east or west half) (dense) west east --------------------------------------------------------------- | | | | | | 21 | 22 | 21 | 22 | | | | | | |---------------|---------------|---------------|---------------| | | | | | | 23 | 24 | 23 | 24 | | | | | | --------------------------------------------------------------- FILE COMPRESSION: The SDTS transfers are stored as compressed "tar" archive files. Each transfer is comprised of several files which are combined with the Unix "tar" command and compressed using the GNU "gzip" utility. To extract the SDTS modules, the following UNIX command could be used: gunzip < hydro.sdts.tar.gz | tar xvBf - (See "FTP SITES" for a list of places were DOS and MAC versions of tar can be downloaded). Note: If you do not have access to gzip the FTP server will uncompress the files as you retrieve them if you omit the gz extension. For example, in a ftp session, to retrieve the file "HR3.hypso.sdts.tar.gz" without compression type: "get HR3.hypso.sdts.tar" Note that the uncompressed files are typically five times larger than the compressed versions and will take five times longer to transmit. Some web browsers will allow FTP retrieval as well. For a list of gzip sites see "FTP SITES". NOTE: Transfer and file names are identical for the east and west half of each quadrangle. Make sure to put the east and west files in separate directories before uncompressing them. FTP SITES: UNIX gzip: ftp://prep.ai.mit.edu/pub/gnu ftp://wuarchive.wustl.edu/systems/gnu MAC gzip and tar: ftp://mirrors.aol.com/pub/mac/util/compression macgzip0.3b2.sit.hqx suntar2.03.cpt.hqx MSDOS gzip and tar: ftp://prep.ai.mit.edu/pub/gnu gzip-1.2.4.tar ftp://ftp.uu.net/systems/ibmpc/msdos/pcroute tar.exe SDTS data and documentation: ftp://sdts.er.usgs.gov/pub/sdts Example FTP: ftp prep.ai.mit.edu user name: password: cd /pub/gnu set binary get quit **** FOR ADDITIONAL INFORMATION VISIT THE SDTS **** **** WEB SITE OR E-MAIL THE SDTS TASK FORCE **** POINT OF CONTACT: U.S. Geological Survey | E-mail: sdts@usgs.gov SDTS Task Force, MS 821 | Web: http://mcmcweb.er.usgs.gov/sdts 1400 Independence Road | FTP: sdts.er.usgs.gov (144.47.162.236)