*PANEL1 Access options by using an "arrow" key followed by the ENTER key or by simply typing the first letter of the menu choice (for example, if you type "P", you will enter the Point Data option). Menu choices are: IMAGE - create color screen pictures of topography, magnetics, gravity, satellite imagery, or data from a user-defined grid. After selecting a data set, select a color palette option (which includes a stored system default, a stored user default, and a temporary user set). AREA - define the geographic area-of-interest. Since each data set has a different resolution (30-second to 10-minute) and different completeness of coverage, IT IS STRONGLY RECOMMENDED THAT WHEN VIEWING AN IMAGE, THE IMAGE OPTION IS SPECIFIED BEFORE AREA OPTION. To select an area, the user must type in latitude and longitude limits or graphically overlay a window on the data. POINT DATA - display earthquake, crustal stress, or thermal aspect data on the screen. Selection options include parameters unique to the data type, as well as symbol and color choices. CONTOURS - display contours that have been pre-computed and stored on the compact disc. These include topography, magnetics and gravity. Options exist in sub-menus to select intervals and colors. BOUNDARIES - reference overlays for examining displayed data. Choices are coastlines (which include country borders), state and county borders, and latitude - longitude grids. GO - an action command to display (or re-display) the data you have selected. SCREEN -allows the user to: (1) title a display, (2) save a display, (3) restore a previously saved display, or (4) clear currently active display parameters. EXIT - returns the user to the Main Menu. *PANEL2 Chose the data image that will appear as a color picture on the screen. Upon selecting a data type, the user will be provided with options for the color palette. To change a color palette after an image has been drawn, simply re-enter this menu item, confirm your data type, and choose a new palette option. Greater detail on all of the following data sets can be found in "DOC" files on the CD- ROM (see Introduction on first screen or the User Manual). Topography (N. America) - display land and marine topography (in meters) using a 5-minute grid. Topography (U.S. - Land/Coast) - designed especially for this CD- ROM. This contains a land 30-second data grid with coverage for the conterminous United States that has been masked to delete offshore values. (Note: The masking deleted historical errors in this popular file.) Thirty-second coastal bathymetry was added to this file. All data are in meters. Caution: Inland waters have some datum shifts. For example, most of the Great Lakes are at elevations of 560-600 feet, and a depth of 10 feet may represent an elevation of 590 feet above sea level. DNAG Magnetics - magnetic data for much of North America (excluding Mexico) on a 2.5-minute grid. The grid was developed from four separate 2-km grids used to generate the Decade of North American Geology maps of the Geological Society of America. MAGSAT Magnetics - a smoothed 2.5-minute grid generated from a 2- degree file. The smaller grid was chosen to facilitate comparisons with the other data sets. DNAG Gravity - a combination of Bouguer anomalies on land and free- air anomalies over water environments. The 2.5-minute grid was developed from a 6-km grid used on Decade of North American Geology maps. Isostatic Gravity - a 2.5-minute grid developed from a 4-km grid of data for conterminous United States. Satellite Imagery - weekly composite values at a 10-minute grid for summer 1986 ("Julian" days 162-168) and fall 1986 ("Julian" days 316-322). AVHRR channels 1, 2 and 5 (representing visible, reflected infrared and thermal infrared, respectively) and computed normalized vegetation indexes are presented. User File - a file unique to an individual user. See the Technical Specifications chapter and the Running Utilities appendix in the User Manual for details on grid structure requirements. *PANEL3 The user has several choices when choosing color representation on an image. Default values for each data type come with the software. The user can temporarily alter the system default values for use during the session or redefine and save new defaults for future use. A restore command is available to re-initialize the system defaults. *PANEL4 Specify a geographical area-of-interest. It is recommended that a user first choose a data type before selecting a geographical area; however, this is not mandatory. First select either a specific NEW area (anything other than the entire limits of the data set) or ALL (the entire data set). If a new area is requested, one may ENTER LIMITS by typing the latitude and longitude, or use a graphical WINDOW IMAGE with a movable rectangle overlaid on an image of the selected data. IMPORTANT NOTE: When using the WINDOW IMAGE, the rectangle that first appears is the exact dimensions of the area that will fill your screen at maximum resolution. Selecting a smaller area will result in an image that is smaller than the screen (which can be expanded by zoom features -- such as "Page-Up" -- discussed in the User Manual). Because each data type represents a different grid resolution, specifying the area limits before the data type can result in very small, "postage stamp"-like images. *PANEL5 If one chooses to ENTER LIMITS, the user specifies degrees and decimal degrees at the prompts. All of the data sets are in the Northern Hemisphere. The left-most limit (170 E) is near the International Date Line and the right-most limit (10 W) is near the Prime Meridian. *PANEL6 The POINT data sets are lithospheric data whose values may be represented by symbols on the screen at distinct locations. The user can define symbols and colors to highlight specific attributes of the data in the display. Each of these lithospheric data sets were developed in support of maps associated with the Decade of North American Geology project sponsored by the Geological Society of America. EARTHQUAKES summarize earth seismicity data FROM 1534 through 1985. STRESS is directional information relating to crustal stress measurements. THERMAL ASPECTS data contain heat flow and thermal gradient values. VIEW MENU returns the user to the main View Menu. *PANEL7 When selecting EARTHQUAKES, choose symbols and colors for the ranges of dates and magnitudes desired. One may use different symbols and colors for different ranges. For example, each year or each magnitude range could have different colors and symbols. Earthquake data covers the time period from 1534-1985 and magnitude values from 2.50 to 8.70. If ranges are specified for both dates and magnitudes, only events which satisfy both ranges will be retrieved. *PANEL8 CRUSTAL STRESS data can be selected by choosing a range of azimuth, from 0 to 180. Also, a stress type can be specified from an acceptable value table, or all types can be selected. Quality constraints can be imposed to specify the minimum and maximum quality accepted. The stress qualities range from A (best) to D (worst), with E (unknown). For each search the user can specify colors to be associated with a directional symbol. By repeating the selection process, different selections can receive unique colors. If ranges are specified for more than one parameter, only data satisfying all ranges will be retrieved. *PANEL9 THERMAL ASPECTS data lets you display either heat flow ranges or thermal gradients or both with a variety of symbols and colors. In addition, minimum and maximum quality constraints can be given. The quality of thermal data ranges from 1 (+/- 5%) to 6 (no quality given). If ranges are specified for more than one parameter, only data satisfying all ranges will be retrieved. *PANEL10 CLEAR FIELDS lets you erase previously selected parameters. One must erase each of the point data sets individually. VIEW MENU returns the user to the main View Menu. Once in the View Menu, the user can continue selecting additional overlay display features, display the current image, or select other options. *PANEL11 BOUNDARY SELECTION - overlays geo-political reference data onto other data layers. In each selection the user can specify colors. COASTLINE plots shore and lake information, as well as international boundaries. There are two options available: GENERAL - is a generalized data file which plots quickly and is adequate for most large displays (e.g., country-wide). DETAIL - is a finer resolution data set which should be used for displays of regions that are much smaller than a country. STATES & PROVINCES displays political subdivisions within individual countries. This file does not duplicate the country boundary information used in the coastline file; therefore, it is recommended that COASTLINE always be used with this option. U.S. COUNTIES will plot county information for the United States. The state boundaries are not included in this file; therefor, it is recommended that STATES & PROVINCES always be used in conjunction with this option. LAT/LONG GRID lets the user superimpose a latitude/longitude grid on top of the image. Options exist to choose specific grid intervals. The grid may be added or removed during the display by using "CTRL-G". *PANEL12 The SCREEN option provides screen utilities. The options are: RESTORE - recall a previously saved screen from your hard disk. SAVE - file a screen image on hard disk for future use. The file name must be 8 characters or less with no extension. CLEAR SCREEN - erase all selection parameters at once and continue with a new selection session. TITLE - label a display. The title must contain 80-characters or less. VIEW MENU - return to the main View Menu. *PANEL 13 The CONTOUR OVERLAY SELECTION menu permits the user to specify data sets which have contours stored on the CD-ROM. The user may choose color presentation of contours from a color palette; additionally, a selection can be made for the contour interval. Each of the data sets presented on this screen correspond to an unlabeled vector file on the CD-ROM. An important constraint on the contour intervals is the recorded resolution. Topography data, for example, have been contoured at 200-foot intervals. Selecting 400-foot intervals plots every other stored line; selecting 1000-foot intervals plots every fifth line. The software algorithm always normalizes the data about the zero- contour interval. Therefore, if a 40 mgal contour interval was selected, the contours would include ...-80, -40, 0, 40, 80.... The TOPOGRAPHY contours were developed from a 5-minute average elevation file which covers all of North America. A contour interval of 200 feet was used. The ISOSTATIC GRAVITY contours, developed by the U. S. Geological Survey, only contain data for the United States. A contour interval of 10 mgals was generated from a modified, projected grid that was developed by the Cooperative Institutions for Geoscience Data Management and Applications (CIGMA). The Decade of North American Geology (DNAG) GRAVITY project compiled a gravity data set that covers most of North America. The DNAG gravity set was developed on a 6-km grid and includes free-air anomalies on oceans and Bouguer anomalies on land. Gravity contours are at 20 mgal intervals. The Decade of North American Geology (DNAG) MAGNETICS project compiled a magnetic data set that covers most of North America. The DNAG magnetics set was developed on a 4-km grid. Magnetic contours have been stored at 200 gamma (nT) intervals. COASTLINE data is provided on the CD-ROM as a reference overlay for the geophysical data. STATE & PROVINCE outlines are available for U.S. and Mexican states, as well as Canadian provinces. U.S. COUNTIES are available for those who wish to see higher base reference resolution for the conterminous U.S. *BOXEGA KEY ACTION (box movements) Up Arrow Move North Left Arrow Move West Right Arrow Move East Down Arrow Move South KEY ACTION (box size) KEY ACTION(box size) t Shrink top T Grow top b Shrink bottom B Grow bottom l Shrink left L Grow left r Shrink right R Grow right KEY ACTION PgUp Increase box size in all directions PgDn Decrease box size in all directions - Decrease action step size + Increase action step size CR Select current screen box coordinates and EXIT geographic select routine Esc Abort current selection; go to Main Menu IF DEFAULT WINDOW SIZE IS : | DATA | PLOT | ENLARGE | RESOLUTION | TIME* | FUNCTION ---------------------------------------------------------------- Unchanged | Full | 2 min | available Enlarged | Decimated | >2 min | unavailable Shrunk | Full | <2 min | available * plot time for 286-8 mhz (386-25 mhz = 50 seconds) *GO Display (or re-display) the data that have been selected on the screen. This includes image, point, contour, and boundary data with the appropriate colors and symbols that have been selected. If no changes have been made since the last screen was displayed for this session, the screen image will be quickly re-displayed from memory. If any changes or additions have been made, the changed data will be read from the CD-ROM and the new image will display data slower rate. Once the image has been created on the screen, there are a number of options available for on-screen data manipulation. These are: Ctrl-G Geographic latitude-longitude grid overlay; off/on switch Ctrl-P Cross section profile Ctrl-T Display title of screen image; off/on switch Ctrl-V Point value display function F3 key Display color scale; off/on switch PgUp Zoom in on lower left quadrant of screen PgDn Zoom out ESC Return to View Menu Enter Return to View Menu *EXIT Leave the View Menu and return to the Main menu. If the user has not done a screen save, the image that one created during this view session will be lost. From the Main Menu, one may run the Tutorial, or return to this menu to view data.