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Geologic map of Washington - southwest quadrant (digital edition)

by Timothy J. Walsh, Michael A. Korosec, William M. Phillips, Robert L. Logan, and Henry W. Schasse

Digital database by Karen L. Meagher and Ralph A. Haugerud

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

This database, identified as Geologic map of Washington - southwest quadrant by T.J. Walsh and others (digital edition) has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.

The pamphlet for this report is also available from:

USGS Information Services
Box 25286
Denver Federal Center
Denver, CO 80225
303-202-4700
303-202-4693 FAX

TABLE OF CONTENTS

INTRODUCTION

The digital transcription is incomplete: offshore folds and faults, the southern limit of the continental ice sheet in the Puget Lowland, the published base map (Washington Division of Geology and Earth Resources map TM-1), geologic unit correlation diagrams, and most of the explanatory material that accompanies Walsh and others (1987) are not present here.

These materials are assembled in four separate files, all available at https://pubs.usgs.gov/of/1999/0382/:

swwadb.tar.gz  compressed Unix tar file containing:
 
 

swwaplt.tar.gz   compressed Unix tar file containing ALL OF THE FILES in swwadb.tar.gz and files necessary to recreate plot files. Additional files are:
 

swwa.rtl.tar.gz   compressed Unix tar file of 2 RTL-format plotfiles, ready for plotting on HP650C or similar plotter. Files produce a map on two sheets, one 50" wide by 36" high, one 30" wide by 36" high.

swwa.ps.tar.gz   compressed Unix tar file of 2 Postscript-format plotfiles, ready for plotting on HP2500CP or similar plotter. Files produce a map on two sheets, one 50" wide by 36" high, one 30" wide by 36" high. These files are uncompressed Postscript for faster processing, they contain PageSize statements, and they set print quality to BEST.

The images below are thumbnails of each map sheet and a fragment of sheet 1. Click on the images to see larger versions.

sheet 1, map  (click to see 400 KB version)	sheet 2, explanation  (click to see 172 KB  version)	6" x 4" fragment of sheet 1  (click to see 328 KB version)

These files were generated with ARC-INFO v. 7 on a Unix (Solaris 2.6) workstation and can readily be uncompressed and un-tarred on a similar system. Utilities for uncompressing and un-tarring these files on various operating systems are available from
       http://www.matisse.net/files/formats.html
and from links at
        http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/public.html

Questions regarding these data should be referred to Ralph Haugerud or Washington Division of Geology and Earth Resources staff. Haugerud or WDGER staff can also provide the digital spatial data in other formats, such as DXF and ASCII lat-long.

    Ralph Haugerud
    USGS @ University of Washington
    Box 351310
    Seattle, Washington 98195
        rhaugerud@usgs.gov

    Washington Division of Geology and Earth Resources
    1111 Washington Street SE
    PO Box 47007
    Olympia, Washington 98504
    phone 360-902-1450

For your convenience, both sheet 1 (7.5 MB) and sheet 2 (672 Kb) are provided in PDF format for viewing

Download Acrobat Reader version 4.0 for free.

OBTAINING DATA FILES

1. On the world-wide Web, go to

http://geopubs.wr.usgs.gov/open-file/of99-382

2. Send a blank magnetic tape (8 mm Exabyte, 2.3 or 5.0 GB capacity) with a letter of request and return address to:

SW Washington Geologic-map Database
c/o Database Coordinator
U.S. Geological Survey
345 Middlefield Road, M/S 975
Menlo Park, CA 94025

Do not omit any part of this address!

Be sure to include with your request the exact names, as listed above, of the files you require. An Open-File Report number is not sufficient, unless you are requesting all files (database package, plot-generation package, and both plotfile packages) for the report.

PLOTTING THE MAP YOURSELF

(1) Download file swwa.rtl.gz, uncompress it, un-tar it, and plot files swwa1.rtl and swwa2.rtl on an HP650C, HP750C, HP755C, or similar plotter that understands the raster transfer language (RTL) subset of HPGL2.

(2) Download file swwa.ps.gz, uncompress, un-tar it, and plot files swwa1.ps and swwa2.ps on an HP2500CP or HP3500CP plotter or other Postscript-capable large-format plotter.

Both sets of files describe a map on two sheets that are 36" high, one 50" wide and one 30" wide, but are rotated to plot out with long axis parallel to paper.

Files are sent to plotters in different ways on different computer systems: on some Unix systems it may work to use the commands

lpr -P<plottername> swwa1.rtl

lp -d<plottername> swwa1.rtl

OBTAINING A PAPER MAP

In the near future the U.S. Geological Survey is planning to provide a plot-on-demand service for map files, such as those described in this report, through Open-File Services. When this service is operational, you may purchase plots from Open-File Services at:

USGS Information Services
Box 25286
Denver Federal Center
Denver, CO 80225-0046
(303) 202-4200
1-800-USA-MAPS
FAX: (303) 202-4695
e-mail: infoservices@usgs.gov

Be sure to include with your request the Open-File Report number and the exact file names of the maps you require. An Open-File Report number and its letter alone may not be sufficient, unless you are requesting plots of all the plotfiles for that report.

You may be able to find a commercial vendor who can plot map files such as these for a fee.

METADATA

MAKING THE MAP DIGITAL

We transformed these coverages from scanner inches into UTM (zone 10) meters, matching tics in the scans to calculated locations. A transformation report is given below:
***************************************************************************
Arc: transform swwa swwa_utm affine
Transforming coordinates for coverage swwa

Scale (X,Y) = (6353.768,6351.697) Skew (degrees) = (-0.016)
Rotation (degrees) = (1.853) Translation = (350925.467,5012888.687)
RMS Error (input,output) = (0.004,22.923)

Affine  X = Ax + By + C
        Y = Dx + Ey + F
  A =         6350.445   B =         -207.166   C =       350925.467
  D =          205.479   E =         6348.317   F =      5012888.687

tic id         input  x         input  y
               output x         output y          x error          y error
------ ---------------- ---------------- ---------------- ----------------
    10            6.052           21.481
             384899.312      5150478.000            7.690           21.146
    12            6.500           30.215
             385959.000      5206037.500          -13.352            4.447
    13           12.480           29.923
             423972.344      5205431.000           10.258          -19.049
    14           12.083           21.187
             423265.969      5149871.000            3.935            3.606
    15           18.118           20.939
             461632.906      5149506.500           12.748           31.231
    16           18.453           29.676
             461986.062      5205067.000          -23.775            8.594
    17           24.154           20.716
             500000.000      5149385.000           21.749          -18.908
    18           24.433           29.461
             500000.000      5204945.500          -19.860          -11.815
    25           29.954           11.797
             538717.312      5093951.000          -12.672          -15.596
    26           36.044           11.657
             577434.500      5094315.500          -31.001          -20.811
    27           42.140           11.558
             616151.500      5094923.500          -13.912           -4.017
    31           48.238           11.498
             654868.250      5095774.500           11.231           16.600
    33           30.191           20.542
             538367.062      5149506.500           25.995           -9.705
    34           36.224           20.407
             576734.000      5149871.000           -0.243           12.260
    35           30.414           29.286
             538013.938      5205067.000          -13.647          -14.605
    36           36.403           29.150
             576027.625      5205431.000           33.635          -10.730
    37           42.264           20.304
             615100.688      5150478.000           10.491           -8.177
    38           42.381           29.055
             614041.000      5206037.500            1.011            7.335
    39           48.303           20.247
             653466.875      5151328.500           10.343           17.943
    40           48.361           28.995
             652053.750      5206887.000          -20.624           10.250
****************************************************************************
Transformation reports for all coverages (contacts and faults, vents, and folds) were identical, strongly suggesting that at least two of the coverages had been transformed to common coordinates prior to our receiving them. Visual inspection of plots made from the coverages suggests that the root-mean-square error of 23 meters given in the transformation report above may approximate the spatial precision of the digitization process.

We carefully checked the attributes of all lines and polygons, trying to remain faithful to the intent of Walsh and others (1987). Identities of several small polygons on the published paper map were ambiguous; these we identified by consulting the appropriate 1:100,000-scale compilation map (see list in Walsh and others, 1987) or, failing that, consulting with T.J. Walsh and J. Eric Schuster.

Some fault segments on the published map are symbolized as normal or strike-slip. Most map readers will carry this meaning to adjoining fault segments, but the extent to which such meaning carries along a fault is commonly ambiguous. We took a conservative approach, classifying most fault segments as fault and no more.

The Description of Map Units was scanned from the published map, processed with optical character recognition software, proofed, and reformatted to file swwa.dmu.

MAP ACCURACY

Locational accuracy of features on geologic maps is rarely defined and this map is no exception. The circa-23 meters spatial precision of the digitization process provides a lower bound on the error with which features are located by this map. Many geologists understand that well-located (continuous line) contacts and faults should be within a millimeter or so on the map of where the feature would be located if the map had no locational error. At 1:250,000 scale, a millimeter on the map corresponds to 250 meters on the ground. This may approximate the accuracy with which features are located on this map.

Presence or absence of faults in a given area on this map should be interpreted with some caution. Sophisticated users of the map will note that the abundance of mapped faults in the Willapa Hills (southwest portion of map) and Columbia Plateau (southeast corner) relative to the southern Cascade Range (east-central part of map) corresponds to the quality of outcrop and depth of geologic knowledge of these areas, not necessarily to a real contrast in the density of faults.

The accuracy with which earth materials are classified by this map is unquantified. Familiarity with some of the geology shown on this map; knowledge of source materials used in compiling the map; subsequent, more detailed geologic study in some areas; and knowledge of the terrain in parts of southwest Washington suggests that the map is reasonably good and that some areas contain significant errors. Misclassification of the age of material is likely to be more common than misclassification of lithology.

A NOTE ON YOUNG FAULTS

COVERAGES, TABLES, AND DATA DICTIONARIES

1) Coverage SWWAG (geologic units, contacts, and faults)

values of LTYPE in SWWAG:

contact
fault
fault dashed
fault dotted
ll strike-slip fault
ll strike-slip fault dashed
ll strike-slip fault dotted
map boundary
normal fault
normal fault dashed
normal fault dotted
rl strike-slip fault
rl strike-slip fault dashed
rl strike-slip fault dotted
thrust fault
thrust fault dashed
thrust fault dotted

FORMATION corresponds to the label on each map-unit polygon, with the
following conventions:
 

Full text names of map units and unit descriptions, placed in the complete Description of Map Units hierarchy, are in swwa.dmu--see DESCRIPTION OF MAP UNITS, below.
 

2) Coverage SWWAS (Structure)

values of LTYPE in swwas:

anticline
anticline dashed
anticline dotted
away monocline
away monocline dotted
plunging anticline
plunging anticline dashed
plunging anticline dotted
plunging syncline
plunging syncline dashed
plunging syncline dotted
syncline
syncline dashed
syncline dotted
towards monocline
towards monocline dotted

There are no points or polygons in coverage SWWAS.
 

3) Coverage SWWAV (Vents)

DESCRIPTION OF MAP UNITS

For example, entry 60 is FORMATION = En, full name = Middle to upper Eocene nearshore sedimentary rocks. Its parent entry is 59, which has full name = Nearshore, a third-rank heading. The parent entry of "Nearshore" is 55, EOCENE SEDIMENTARY ROCKS, a second rank heading. The parent of 55 is 1, SEDIMENTS AND SEDIMENTARY ROCKS, which has a parent of 0, indicating it is at the top of the hierarchy.

File swwa.dmu can be readily converted into a queryable database file, but not an INFO file because most unit descriptions are longer than the 320-character maximum size of INFO items. File swwa.dmu also can readily be transformed into a standard formatted DMU--indeed, this is how we created DMU.doc and its offspring dmu*.prn.

IMPORTING DATA INTO ARC-INFO

&sys gzip -d swwadb.tar
&sys tar -xvf swwadb.tar
import cover swwag swwag
import cover swwas swwas
import cover swwav swwav

MAKING A MAP FROM THE DATA A digital representation of the base map used by Walsh and others (1987) is not available. Instead, we provide digital topography and instructions necessary to plot a map with a shaded-relief base. The digital elevation model (DEM) is a composite of quadrangle-format 10-meter and 30-meter DEMs, resampled at 60-meter intervals. The original DEMs are available from the U.S. Geological Survey (http://edcwww.cr.usgs.gov).

The technique we use to make the geology-on-shaded relief map requires the GRID module of ARC-INFO.

A map can be made from the database by

(1) Importing digital geologic map data into ARC (above); but use file swwaplt.tar.gz (gzip -d swwaplt.tar; tar -xvf swwaplt.tar).
2) Importing cover swwaclip into ARC
    Arc: import cover swwaclip swwaclip
(3) Running macro imptswwazg.aml from the ARC prompt to convert BIL files for DEM swwazg to an ARC grid
(4) Running macro mkswwa.aml from the ARC prompt. This will take awhile. The macro

Loads text file swwa.unit into INFO file SWWA.UNIT which describes symbolization of map units
Sets up a relation between the geologic unit coverage and SWWA.UNIT
Dissolves the geologic map to a geologic polygon coverage (swwapcov)
Prepares a line coverage of faults, swwafcov, for more-pleasing symbolization of ornamented fault lines
Creates a clipgrid (swwaclipg) from cover SWWACLIP
Converts geologic polygon coverage to hue (swwahg) and saturation (swwasg) grids
Prepares a shaded-relief image from the DEM (swwashdg)
Converts the shaded-relief image to a value grid (swwavg)

(5) When this preparatory work has been done, run macros plotswwa1.aml and plotswwa2.aml from ARCPLOT to

plotswwa1.aml:

Plot a base-plus-geologic unit color layer with the GRIDCOMPOSITE HSV
command
Plot overlay patterns (uses inkjetpat.shd and fnt035 for patterns)
Plot contacts
Plot faults
Plot volcanic vents
Plot polygon labels
Draw a lat-long graticule
Draw a title box

plotswwa2.aml:

Plot encapsulated Postscript files of the Description of Map Units (DMU)
Plot key-boxes for the DMU
Draw text for a line-and-vent legend

Positioning of DMU key-boxes is made easier by drawing a 1" cyan grid over the relevant portion of the map. (Enable &call plotgrid, line 21 in plotswwa2.aml.)

Shades and patterns we provide are similar to, but not identical with, those of Walsh and others (1987). These shades and patterns have been optimized for an HP650C plotter. If the map is prepared with these shades and patterns and output to other devices it will not look the same! For plotting on other devices and at other scales it may be necessary to modify the shades and patterns and (or) modify the macros mkswwa.aml, plotswwa1.aml, and plotswwa1.aml.

We chose not to plot fold axes, though this may be easily done.

The techniques used to generate a geology-on-shaded relief map are further elaborated by Haugerud and Greenberg (1998).

REFERENCES CITED

Walsh, T.J., Korosec, M.A., Phillips, W.M., Logan, R.L., and Schasse, H.W., 1987, Geologic map of Washington - southwest quadrant: Washington Division of Geology and Earth Resources, map GM-34, 28 p., 1 pl., scale 1:250,000, and accompanying explanatory sheet.