TAILORING ArcInfo FOR GEOLOGICAL MAP PRODUCTION

Victor Dohar
Cartographic Applications Specialist
Earth Sciences Sector, Natural Resources Canada

Abstract

The Cartographic Services Section of the Earth Sciences Sector, Natural Resources Canada is world renowned for the production of high-quality geological maps using ArcInfo. Twenty-one SPARC workstations, electrostatic plotters and servers complement the cartographic staff in their production requirements. Data input from the Geological Survey of Canada scientists are accepted in various digital formats, as well as traditional hardcopy manuscripts which are either scanned and vectorized or digitized. To assist the cartographers in the production of geological maps ArcInfo has been tailored to increase performance using extensive AMLs, graphical user interfaces, plotting routines for surround information, production and database standards, and complex geological symbolsets. These tools and procedures are constantly being revised in order to accommodate various data inputs and to further streamline the production process for greater efficiency. Geological maps are created as PostScript files and are plotted on electrostatic plotters for on-demand publishing or colour separated to negatives on large-format high-quality imaging systems for offset printing. Several digital datasets have been released on CD-ROM and plans include releasing and browsing datasets via the Internet.

Introduction

The Cartographic Services Section of the Earth Sciences Sector is responsible for the production of high-quality geological maps. After several years of research and development the section began using ArcInfo in 1994 for digital map production. Several procedures have been created to assist cartographers in all facets of mapping. These procedures consist of routines, AMLs and menus that in-turn prompted the creation of a custom made graphical-user-interface named WIMP (Windows Interface for Map Production). The use of these features for automating data input and creation, editing and plotting data has in essence tailored ArcInfo for creating geological maps.

Custom Features

ATOOLs and AMLs

AMLs used for the production of maps are stored in an ATOOL directory. This allows AMLs to be executed as ArcInfo commands without the need of the &RUN directive. Syntax rules for passing arguments to these AMLs are the same as for ArcInfo commands. The ATOOL directory is stored in a different location than the installation directory of ArcInfo, and made available to all workstations across the local area network. This configuration allows for easier administration of files.

To be able to use an ATOOL directory it must be stated at some point during an ArcInfo session. This is most conveniently accomplished by using a .arc file stored at the user's login location that is executed every time ArcInfo is started. Its format is similar to an AML and can contain other commands to initalize ArcInfo for the workstation. The following is an example of a user's .arc file:

&atool /home/gsc70/amls
&term 9999
DISPLAY 9999 SIZE 800 800
DIGITIZER altek /dev/ttya:9600:8bit:none
WIMP

WIMP

The purpose of WIMP is to assist cartographers in the production of geological maps using user-friendly menus and applications. It contains commands from the modules ARC, ARCEDIT and ARCPLOT that are related to map production. WIMP consists of approximately 500 AMLs and menus, and is structured similarly to the ATOOL directory for AMLs. A pulldown menu exists for each of the three modules that in turn displays various form menus. WIMP is automatically displayed on the screen when ArcInfo is started by using a .arc file (see above).

GSC Symbolsets

Custom made geological symbolsets for lines, markers (points), shades (area fill) and text are used in the plotting of geological maps. The textset contains a customized PostScript font of geologic age symbols that is mapped to specific characters on the keyboard. Two shadesets exist, one for solid colour fills and the other for geological pattern fills. When producing PostScript files for high-quality offset-printing, the solid colour fill shadeset is capable of any three-colour combinations of cyan, magenta, yellow and three other spot colours. These symbolsets are constantly being updated with new symbols as required. WIMP also incorporates tools for managing IGL fonts and editing its patterns that are used to define the symbols in each symbolset.

Production & Database Standards

The Cartography section has developed its own Production and Database Standards in order to streamline the production process and to have consistency and uniformity of feature attributes. Although the database standard does not adhere to a grand database scheme, it is none the less structured in such a manner that it can be incorporated into any database structure.

Data Input & Creation

The initial steps of any mapping project involves the gathering and input or the creation of data. Preliminary compilation of geological data from geologists is imported from various CAD packages. Topographic base data is obtained from Geomatics Canada based on the National Topographic Database (NTDB) at scales 1:50,000 and 1:250,000, or from National Atlas of Canada at smaller scales. The digital data in most cases is imported into ArcInfo as DXF files. Some other forms of data are required to be created in ArcInfo, such as a map border and a water mask, necessary elements of a published geological map. These routinely performed procedures have been implemented in WIMP through the use of AMLs and menus in order to automate them as much as possible.

Importing DXF Files

Majority of data input from various CAD packages are imported into ArcInfo as DXF files. These DXF files can contain any combination of DXF entities, but mainly consist of lines, points, text and attributes. Lines are converted to arcs, points are converted to labels, and text and attribute entities can be converted to either labels or annotation depending on the feature they represent and how they were exported from the CAD package. The usual method of converting a DXF file to a cover is to first execute the command DXFINFO, that reads the DXF file and displays information about it. Based on this information, all or specific layers can be converted to a cover using the DXFARC command. The last two steps involve building line and/or point feature attributes for the cover and joining the DXF info files cover.ACODE and/or cover.XCODE to the cover's arc and/or point feature attribute table.

In WIMP, an AML automates this four-step procedure with the use of a menu (shown below) that displays the information contained in the DXF file. The information is much like what would be returned from executing the DXFINFO command, yet the user can select which DXF entity to convert from each of the layers contained in the file by checking the appropriate box. There are also fields for entering the cover name to create and arguments associated with the DXFARC command. The required feature attribute tables are then built and joined to the DXF info files.

The AML creates this menu by writing the results of the DXFINFO command to a watch file. The textual information in the watch file is used to construct the menu. At the top, in the menu file where comments are permitted, layer names and the DXF entities they contain are recorded, which are used for assigning values to variables in the menu itself. The menu is saved in the user's workspace and can be accessed any time in the future, as long as the same DXF file exists.

Creating a Water Mask

Bodies of water on most geological maps do not contain any colour fill; in other words, they are white. Geological data received from geologists usually extends into bodies of water mainly to close geological polygons or units. Since PostScript files are used for published maps, its masking capability is used to mask these unwanted geological units. This requires hydrology features to have polygon topology in order to logically select bodies of water and shade them white.

In the case of NTDB data where hydrology features do not contain polygon topology, the water mask AML creates topology and polygon labels coded as either land or water. One prerequisite is required: any bodies of water at the neatline are to be closed by adding what is called a pseudo shoreline. Displayed below are the general steps involved in creating a water mask.

Original hydrology data with pseudo shoreline added to close body of water
Result from water mask AML. Polygons -IDs coded, 1 for water and 2 for land
Example plot of geology with watermask and hydrology

Another possible method to achieve the same results would be to combine the geology and hydrology data, and edit those geological areas that fall in bodies of water. However this can be a very time consuming process and it is preferred to keep the two datasets separate in their original form, allowing for ease of data management and digital data releases.

Creating Map Borders

Map borders on geological maps are plotted according to a set of standards and specifications, and based on the scale of the published map. The border can be any map projection (usually Transverse Mercator, UTM or Lambert Conformal Conic) and the neatline limits can be any longitude or latitude value. To construct a border the publication scale, and longitude and latitude extremes of the map are required to be entered in the Create Map Border menu. A projection file with an input projection defined as Geographic and an output projection defined as the publication projection must also be specified. Default values for graticule and tick intervals are automatically set based on the publication scale, however these can be changed.

Sample image of map border The border AML then creates all the border features, including annotation for longitude and latitude tick values, and polygon labels. The only manual task involved is to delete the polygon label for the map area and code the remaining polygon labels as either white or black. The masking ability of PostScript is again used at the plotting stage to mask any plotted features that extend beyond the neatline.

Editing Data

The majority of time to produce a map involves editing data received from the geologist. This includes the assurance that features are properly attributed, in accordance to the Database Standards, topologically, geographically and symbolically correct. Annotation or textual information also has to be added to the map in order for it to be read in a legible manner. With the use of WIMP and menu enhancement techniques, considerable savings are made in the time required to edit data.

WIMP in ARCEDIT is designed to edit arcs, labels, polygons, annotation, tics, nodes, links and group features. Where applicable, attribute data can also be edited with the use of logical selections and calculate expressions. The main pulldown menu is used for specifying the edit feature, performing cover operations, managing the display environment and editing settings, performing attribute operations, and accessing the many special routines that WIMP provides. A few of these routines and WIMP enhancements are listed below.

WIMP Enhancements

When exiting from ARCEDIT the edit session can be saved and written to a file. The edit session consists of all opened edit covers and its edit feature, draw and back environments, size and position of all graphic windows, settings for editing, snapping, scaling, symbolizing, and WIMP environment variables. Upon returning to ARCEDIT a previously saved edit session file is selected and is executed like an AML that re-establishes the edit session. With this configuration, different edit sessions can be re-established.

The menus of WIMP and the widgets they contain are designed to be user-friendly and occupy as little space as possible. This is accomplished by assigning two executable strings to a widget. See The Power of QUERY below.

Each edit cover has its own drawing, editing, and snapping environment. Switching between edit covers re-establishes these environments. In addition, the previous edit feature and corresponding edit menus are also re-established.

Unlimited number of user-made or custom menus can be displayed alongside and interact with WIMP using global variables. AMLs can also be executed as needed.

To assist in the placement of annotation features, line, point and polygon features can be symbolized to the publication scale. Furthermore, WIMP provides several menus to improve the performance of editing and adding annotation. See Adding and Editing Annotation for more information.

A Multi Move button in feature edit menus allows all features to be moved individually without repeatedly pressing Move and Select buttons. Using the mouse, the first coordinate to select a feature also becomes the from coordinate for the MOVE command, requiring only the to coordinate to be entered. The process repeats itself until the nine button on the mouse is pressed. This procedure is particularly useful in moving annotation/textual information.

WIMP provides the ability to OOPS to the beginning of the edit session.

Frequently repeated edits consisting of a series of commands can be entered as a command string in the Command String menu that will be listed as a selection in a scrolling list. To execute the command string ADD; EXTEND; SPLINE select it from the scrolling list with the left mouse button. An AML actually executes the command string and can also save and restore the strings to a file for future use.

A digitizer menu is included to edit only arcs, labels and nodes. It also interacts with WIMP including the ability to select any of the first seven command strings from above.

Instead of using the DYNAMICPAN command or the Pan/Zoom options of each graphic window a panning menu allows a selected graphic window to pan in any direction with 0-15% overlap.

The Power of QUERY

The QUERY option of widgets in form menus is used extensively making it possible for widgets to have two actions. On a three-button mouse, pressing the left/select button over the widget will execute the widget's RETURN string, while pressing the right/adjust button over the widget will execute the widget's QUERY string. The result is a user-friendly interface and a reduction in widgets and menu size. As an example the Delete button in edit menus is coded as:

%delete button query 'SELECT MANY; &if [show number select] > 0 &then; ~
DELETE' Delete &if [show number select] = 0 &then; ~
SELECT MANY; &if [show number select] > 0 &then; DELETE

This configuration allows for three scenarios:

If selected features are to be deleted, press the Delete button with the left mouse button
If there are no selected features and some are to be deleted, press the Delete button with the left mouse button prompting a selection
If selected features are not the set to be deleted, press the Delete button with the right mouse button prompting a new selection

In all scenarios, the DELETE command is not executed if no feature is selected.

Adding and Editing Annotation

Four properties that determine the characteristics of annotation, that are stored as pseudo items, are text string, size, font or text symbol and justification at the point where it is added. A menu (shown below) is used to specify these properties using various widgets, along with an AML, for adding or editing selected annotation.

Displayed at the top is the publication scale of the map. The size is specified in points, however the actual size is measured in cover units, calculated based on the publication scale and unit of measurement (meters, feet or inches).
The text symbol can be entered or selected from a listing of text symbols in the GSC textset. When using a subclass name supported by the GSC Database Standards the corresponding text symbol is set automatically.
The text string can be entered or obtained from the value of an attribute item.
The placement method must be specified, by entering points with the mouse, along an existing arc or at 90 degrees. Annotation is then added by selecting one of twelve justification points.

When editing annotation, the four properties in the Add/Edit menu are updated to that of a selected annotation. To apply changes made to any of the properties in the menu to the selected annotation, the right mouse button is pressed over the corresponding widget. Other menus exist for replacing the text string with a value of an attribute item, and for miscellaneous properties such as aligning stacked annotation, and fitting annotation between two points.

To achieve greater accuracy in positioning annotation, line, point and polygon features can be symbolized to the publication scale. In addition, an AP file can be used containing ARCPLOT commands to plot other cover features. Either of these two methods display cover features as if they were plotted at the publication scale.

To further assist the editing capabilities of annotation, the find and replace procedure that is common to document editors is incorporated into a menu and an AML. This procedure applies to all annotation features in a subclass, where a matching find string is replaced with the replace string.

Plotting Maps

Maps at the GSC are published in one of two formats, on-demand electrostatic plots or high-quality offset printing. In either case, a graphics file of the map is created in ARCPLOT and is then used by the SEPARATOR command to create a PostScript file. For offset printing, separate PostScript files of each colour are created set to a resolution of 2400 DPI. These files are then processed and plotted on large format high-resolution image setters to create the final printing negatives. PostScript files for on-demand electrostatic plots are processed in the plotter's native language and stored on database for easy access.

Varieties of routines, menus and AMLs have been developed to assist the cartographer in the plotting of geological maps. These include AMLs for plotting map features, creating geological legends, and plotting surround information.

Plotting Menus & AMLs

Plotting map features and surround information is a repetitive and time-consuming process. To speed this process up, a Plot Map menu and an AML are created that is specific to the map. This allows the map to be plotted any number of times. First, the menu is used to select the features to plot, and whether to plot the map to the display or to create a graphics or PostScript file along with the name of the file. Next, the plotting AML is executed and plots the selections accordingly. Use of a plotting AML provides a consistent structure and a logical flow to the plotting of map elements, and controls the placement of them with greater precision. Coded in the plotting AML are the map-to-page environment settings, symbolset selections, feature plotting commands for each map element, and the plotting of surround information. By adhering to the Production and Database Standards, the plotting menu and AML files can be applied to other maps with minor modifications.

Surround Information

Surround information is composed of objects, such as the map legend, title block, scale bars, logos, location map, credits, descriptive notes, insets and figures that occur on most maps. To include these objects on a map in an efficient manner, separate AMLs exist for each of them. These AMLs exist in an ATOOL directory and therefore they are recognized as ARCPLOT commands. The same ArcInfo syntax rules for passing arguments are applied to these commands/AMLs. Other surround objects such as descriptive notes, figures and special logos are plotted on the page as EPS files.

Geological Map Legend

Along with the geological data received from the geologist, the geological legend, or the description of each unit, is also included in an ASCII text file. Geological legends are very complex, including different fonts, shapes, colours, formats, symbols, patterns, etc... The LEGEND command/AML reads the ASCII text file that is embedded with special keywords to achieve the graphic elements of a geological legend. These keywords use the same syntax rules as in ArcInfo, and are used to plot boxes, unit identifiers, brackets, descriptions of each unit, headings, colour fills, patterns, and irregular shapes. Embedding the ASCII text file with these keywords and altering any of the default values allows great flexibility and control to plot various formats of geological legends.

Scale Bars

Geological maps are published at different scales, ranging from 1:5,000,000 to 1:10,000. The SCALEBAR command/AML will plot the required scale bar according to publication specifications. Length of the scale bar, total number of division and subdivision to the left of 0 can be specified.

Examples of scale bars

Other Surround Elements

Departmental logos, crests and location map (shown below) are a few objects that encompass surround information. These objects are also plotted with their own command/AML (click on image for corresponding AML). Logos and crests can be plotted at a specific point on the page layout or linked to the map border. Depending on the publication scale, the location map displays either the outline of the map or a dot, referenced by latitude and longitude values.

Examples of surround information

Conclusion

These procedures mentioned above for inputting and editing data, and plotting maps have greatly improved the methods of map production. The custom features, such as WIMP, AMLs, GSC symbolsets and Production and Database Standards, are continously evolving to meet the increasing demands for streamlining map production and faster map ouput. No doubt this will continue as advancements in software and hardware expand our capabilites, ensuring the cartographic section remain world renowned for our geological mapping.

Footnote

Some links to the AMLs and menus may not execute on your work station when downloaded as they are excerpts from WIMP and may contain global variables set in other AMLs and menus not included with this document. Furthermore no guarantee is made by the authors or Natural Resources Canada regarding the accuracy of these AMLs or menus or their proper execution on all systems.

If you are interested in obtaining a version of WIMP or any of the GSC symbolsets, please contact the author below via email with your request.

Victor Dohar
Cartographic Applications Specialist
Earth Sciences Sector
Natural Resources Canada
601 Booth Street
Ottawa, Ontario, CANADA
K2J 1W7
Telephone: (613) 996-9355
Fax: (613) 952-7308
Email: vdohar@nrcan.gc.ca