Applications: Making Topographic Maps · Topographic maps produced and published by government agencies usually include both physical and cultural features, making the maps useful

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Making Topographic Maps

MakingTopographic

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MakingTopographic

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TNTmips®

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ApplicationsTOPO

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Before Getting Started

You can print or read this booklet in color from MicroImages’ Web site. TheWeb site is also your source for the newest Getting Started booklets on othertopics. You can download an installation guide, sample data, and the latestversion of TNTlite.

http://www.microimages.com

TNTmips provides a variety of tools for working with map data and making topo-graphic maps that can be printed or distributed as an electronic atlas. This bookletis intended as a general guide to making topographic maps in TNTmips. Using asample map layout, it discusses how the different data layers can be prepared andassembled, and illustrates the type of results you can achieve with your own datausing TNTmips.

Prerequisite Skills This booklet assumes that you have completed the exercisesin the tutorial booklets Displaying Geospatial Data and Navigating. Thoseexercises introduce essential skills and basic techniques that are not coveredagain here. Please consult those booklets for any review you need.

Sample Data The data used to prepare the map shown in this booklet are distrib-uted as sample data with the TNT products. Although this booklet does notinclude exercises with step-by-step instructions on how to use this data, you maywish to view the different data layers and experiment with them before you beginworking with your own map data. In particular, this booklet refers to the sampleProject File MONTARA in the TOPOMAP data collection.

More Documentation This booklet is intended only as an overview of usefulstrategies for preparing and assembling geospatial data layers to make geologicmaps. As different tasks and procedures are discussed in the text, references areprovided to appropriate tutorial booklets that provide exercises introducing thetools for performing those tasks in TNTmips.

TNTmips® Pro and TNTmips Free TNTmips (the Map and Image ProcessingSystem) comes in three versions: the professional version of TNTmips (TNTmipsPro), the low-cost TNTmips Basic version, and the TNTmips Free version. Allversions run exactly the same code from the TNT products DVD and have nearlythe same features. If you did not purchase the professional version (which re-quires a software license key) or TNTmips Basic, then TNTmips operates inTNTmips Free mode.

All of the objects in the sample MONTARA Project File are useable in TNTmips Free.

Randall B. Smith, Ph.D., 29September 2011©MicroImages, Inc., 2002–2011

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Welcome to Making Topographic MapsNo other type of map has wider applications in modern society than the topo-graphic map, one that depicts the local shape of the land surface using contourlines (lines of constant surface elevation). Topographic maps produced andpublished by government agencies usually include both physical and culturalfeatures, making the maps useful in municipal planning, civil engineering, water-shed and other environmental studies, design of communication systems, andoutdoor recreation, among others. Traditionally, topographic maps have beenpublished in printed form, but digital forms of topographic map data are becomingwidely available in some countries. In digital form, topographic map data can becombined readily with othertypes of digital map data toproduce specialized maps thatcan be printed or distributedas an electronic atlas.

The software tools inTNTmips give you the meansto create and assemble all ofthe necessary components ofa topographic map. This book-let provides an overview oftopographic map-making withTNTmips. For each map com-ponent, references areprovided to exercises in other Tutorial booklets that provide provide step-by-step instructions for the relevant operations. The topographic map included withthis booklet was prepared and printed entirely in TNTmips using publicly-avail-able digital map data produced by the United States Geological Survey along withdata that I digitized from a scanned map. (The map layout and all relevant data arein the MONTARA Project File distributed with the booklet.)

In addition to topographic contours, most topographic maps show hydrologicfeatures (streams and rivers, lakes, and springs) and may use color patterns toindicate the distribution of vegetation and urban areas. A variety of culturalfeatures may be included: transportation features (roads and highways, railroads,and airports); boundaries of administrative subdivisions (counties and cities);and locations of prominent public buildings, such as schools, hospitals, andgovernment offices. All of these map elements can be represented most conve-niently using the vector data format in TNTmips, which supports the use of point,line, and polygon elements to represent map features, and also incorporates textlabels.

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Contour Lines and LabelsContour lines distinguish a topographic map from other types of map. Topo-graphic contours are lines of constant ground surface elevation, and the spatialpatterns of contours allow experienced map-readers to visualize the shape of thecontoured surface. Contours are created with a constant elevation incrementbetween sucessive lines, known as the contour interval. The contour intervalvaries with the scale of the map and how wide a range of elevations (relief) themap area includes. Contour lines with elevations divisible by some larger roundnumber are designated as major contours and drawn with a wider line. For exam-ple, the sample Montara Mountain map has a contour interval of 25 feet, andcontours with elevations divisi-ble by 100 feet are shown asmajor contours.

When I assembled the MontaraMountain map data, the contourdata were already available in avector file format with an eleva-tion value associated with eachline, so a simple import opera-tion was all that was needed tocreate a contour vector object inthe Project File. TNTmips sup-ports import from a variety ofvector and CAD data formats (see the tutorial booklet Importing Geodata foradditional information). If you need to create contour line data, TNTmips alsoprovides several methods that are discussed on subsequent pages.

Strategically-placed contour line labels identify the elevation for key contourlines in each subarea of the map. The Spatial Data Editor in TNTmips allows youto create text labels for contour lines automatically using the elevation valuesstored in an attached database table. The Editor’s Auto-Generate Labels opera-tion is a general-purpose tool for creating labels for any element type, while thethe Set Line Labels tool is especially tailored for adding labels to contours. Whenyou create the labels you can turn on a Clip Under Label option that will automat-ically hide the segement of contour line beneath each label. The tutorial bookletAdvanced Vector Editing provides exercises on both of these procedures.

Separate line widths for major and minor contours can be set up by styling thelines for display using a CartoScript. The tutorial booklet Using CartoScriptsprovides several sample scripts designed for styling topographic contours.

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Contours and Streams from a DEMIf contour lines are not available indigital format for your area, you haveseveral options for creating them.You may be able to obtain a digitalelevation model containing griddedelevation values for the area. If so,you can then create vector contourlines from the elevation raster usingthe Contouring operation in the Sur-face Modeling process. Severalcontouring methods are providedthat allow you to set the contour in-terval and starting and ending valuesfor creating contour lines. The pro-cess creates a 3D contour vector withthe elevation recorded as both theminimum and maximum Z value foreach line. Additional informationand sample exercises on contouring can be found in the tutorial booklet SurfaceModeling.

You can also extract stream lines from an elevation raster using the Watershedprocess. The process automatically fills spurious pits and depressions in the

elevation raster, computes thepatterns of downslope flow ofwater over the landscape, andcreates a flow paths vector withlines representing potentialstream lines. You can adjustseveral parameters to vary thedensity and other characteristicsof the stream network. For moreinformation and sample exercis-es, consult the tutorial bookletModeling Watershed Geomor-phology.

Color-coded elevation raster overlaid withcontours created from it in the SurfaceModeling process.

Vector stream lines computed by the WatershedProcess from the elevation raster.

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Auto-Trace Lines from a Scanned MapIf the only starting data for your project is a paper topographic map, and you haveaccess to a scanner, you can scan the map to create a map raster. After additionalprocessing you can automatical-ly trace contours, hydrologicfeatures, or any other line featurethat is represented by a uniqueset of colors.

Begin by making a high-resolu-tion color-composite scan of themap, then georeference the re-sulting raster object (see thetutorial booklet Georeferencing).You can then use the Color Bina-rization process (on the Process/ Raster / Filter menu) to sepa-rate the colors representing thedesired lines and output the re-sult as a binary raster (with value1 for cells representing the linecolors).

Contours auto-traced from a binarizedscanned topographic map, ready forcleanup in the Spatial Data Editor.

Binary raster (cells with value 1 in black)from brown colors of major contour lines,created by the Color Binarization process.

The Auto-Trace process con-verts the binary raster to vectorlines. You can automatically ap-ply various vector filters toreduce the number of extraneouslines and bubble polygons in theoutput vector (see the tutorialbooklet Digitizing Soil Maps forexercises on Auto-Trace). Youcan then use the Spatial Data Ed-itor to close remaining gaps inthe contours, delete survivingextraneous lines and polygons,and assign Z-values to the finalcontour lines. For informationon these procedures, see the tu-torial booklet Advanced VectorEditing.

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Layers, Labels, and Styles

Line symbols for Highways and Roadslayers and a highway point symbol. Icreated the Highway vector by extractingthe appropriate lines from the Roadsobject. Eliminating highway-roadintersections in the Highways objectresulted in better rendering of the dashedline patterns for secondary highways.

Polygon fill styles for vegetation andurban areas, point symbols for schools,and a polygon label for the city name.

Once you have prepared the contour line vector object for your topographic map,you will need to assemble the data for hydrologic, cultural, and any other featuresyou want to include on the map. The map data can be separated into as manydifferent spatial objects as you want. The map group in the sample Montara maplayout (Group 1) includes thirteen separate vector ob-jects plus a map grid generated in the layout (discussedsubsequently).

You can create labels for any vector objects in the Spa-tial Data Editor by manually adding text or fromdatabase entries using the Auto-Generate Label oper-ation discussed previously. The layers in the Montaralayout include labels for point symbols representingschools, line labels for some highways and roads, andpolygon labels for cities, among others. See the tuto-rial booklets Editing Vector Geodata and AdvancedVector Editing for more information. The TNTmipsStyle Editor lets you design vector point symbols, linestyles, polygon fill styles and text styles. You can usevarious colors and design line patterns and bitmap filland hatch patterns for polygons. You can find more information about setting upstyles in the booklet Creating and Using Styles.

You will need to carefully consider the layer order and style color choices toinsure that proper emphasis is given to the appropriate data. In this layout the

two vector layers that required solid poly-gon fills (objects Built and VegSurfCover)were placed on the bottom so that all othermap elements were drawn on top of thesecolored backgrounds.

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Map LegendsYou can easily create simple or complex legends for the various data layers ofyour topographic maps. You can add specialized legends for rasters (color sam-ple and color scale) or for individual element types in vector objects (points, lines,and polygons), or combine legend information for multiple layout objects in asingle multi-object legend. Multi-object legends also provide a graphical editorthat lets you drag legend entries to new positions and preview the results.

Legends in map layouts automatically use the sets of styles you have set up forvector elements to generate a set of corresponding legend samples. You canchange the size of the legend samples, reorder them, and edit the text explana-tions. Multi-object legends also let you use word-wrap and text justification toprovide a professional look to longer legend entries.

Due to space constraints, the legend on the attached Montara topographic mapis confined to an explanation of the road classification and highway symbols.The illustration above shows an expanded legend that could be constructed forthe map, incorporating line and polygon hydrologic features and an explanationof the land cover symbology. This sample was created as a single multi-objectlegend using information from three different vector objects in the layout. Youcan find more information about legends in the tutorial booklet Making MapLayouts.

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Other Map ComponentsOther cartographic elements of a topographicmap can be created easily in a map layout us-ing the Layout Controls window. You shouldconsult the tutorial booklet Making Map Lay-outs for instructions on how to create the layoutelements shown here.

You can set up one or more map grids for yourmap using any of the many map projectionssupported by TNTmips. The Montara topo-graphic map includes one UTM map grid as alayer in Group 1 (which contains all of the lay-ers for the map itself). The Map Grid LayerControls let you set up the extents, interval,and graphic elements for a grid. I set up themap grid to show only border tick marks andlabels.

You can easily add one ormore scale bars to providegraphic scales for the map.You can control the length,intervals, labeling, and bar

styles. The verbal scale and contour interval annotation shown here are textelements. You can add any number of text elements to a layout to create titles andother anotations using various fonts and styles. Each element in a map layout isa group that can be positioned separately on the page and is attached to eitherthe page or to another group. I attached the feet and kilometer scales, verbal scaletext and contour interval text to the mile scalebar, so that repositioning that scale-bar moves all of the attached elements as well.

The declination graphic used in the Montara map layout is an SML (SpatialManipulation Language) script layer. The script uses geographic information

from the map group to draw the graphic with ap-propriate angles and to supply the relevant textlabels. SML display layers are discussed in thetutorial booklet Writing Scripts with SML.

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Use Your Language

Line labelsand linelegend textfromdatabaseentries inFrench.

Street name labels from database entries in Turkish.

MicroImages has clients using the TNTproducts in many countries around theworld, working in many different languag-es. TNTmips has been designed so thatyou can create maps and other displayproducts that have any combination ofinternational fonts and languages.

The TNT products support the use of 8-bit and Unicode (16-bit) character setsand standard Windows and Macintoshlanguage entry methods and keyboardlayouts. You can select any installed in-ternational font as an interface font thatwill then appear in text entry dialogs, andseparately select fonts for styling vectorlabels, legend descriptions, or text anno-tations.

When you set up database tables youcan create explicit Unicode String fields.With a Unicode interface font selected and the appropriate keyboard entry set-ting for your operating system, you can enter all the characters needed for text inyour language into the table. When you auto-generate text labels for map ele-ments using the database entries, the labels will appear with the same characterset specified in the table. For more information on using your language, consultthe tutorial booklet Changing Languages (Localization).

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Templates for Map ProductionTopographic maps are usuallyproduced in a series of adjacentquadrangles of the same size andscale. Maps in these series sharea similar layout and many invari-ant elements such as scale bars,legends, and various annota-tions. TNTmips provides an easyway for you to reuse commonlayout components while pro-ducing a series of similar maplayouts. After setting up the lay-out for the first map, save it as atemplate. Before saving the tem-plate, you can designate whichgroups are to be used “as-is”,without change. (Scale bars andlegends are automatically reused

without change.) Other groupsare treated as replaceable.

When you open a template, youare prompted for the new con-tents of any replaceable group,while the “as-is” groups are load-ed directly. If a replaceable groupincludes a map grid, the map gridis loaded automatically and itsextents are adjusted to the ex-tents of the new group contents.You can find an extended discus-sion of templates in the tutorialbooklet Making Map Layouts.

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Making Topographic MapsAdvanced Software for Geospatial Analysis

MicroImages, Inc.

MicroImages, Inc. publishes a complete line of professional software for advanced geospatialdata visualization, analysis, and publishing. Contact us or visit our web site for detailed prod-uct information.

TNTmips Pro TNTmips Pro is a professional system for fully integrated GIS, imageanalysis, CAD, TIN, desktop cartography, and geospatial database management.

TNTmips Basic TNTmips Basic is a low-cost version of TNTmips for small projects.

TNTmips Free TNTmips Free is a free version of TNTmips for students and profession-als with small projects. You can download TNTmips Free from MicroImages’ web site.

TNTedit TNTedit provides interactive tools to create, georeference, and edit vector, image,CAD, TIN, and relational database project materials in a wide variety of formats.

TNTview TNTview has the same powerful display features as TNTmips and is perfect forthose who do not need the technical processing and preparation features of TNTmips.

TNTatlas TNTatlas lets you publish and distribute your spatial project materials on CD orDVD at low cost. TNTatlas CDs/DVDs can be used on any popular computing platform.

Indexauto-generate labels.............................4,7Auto-Trace process...............................6CartoScript.............................................4Color Binarization process........................6contour interval......................................4contour lines (contours)......................3-6contouring..............................................5digital elevation model...............................5georeference...........................................6label element (vector).......................3,7,10language, changing..................................10legend............................................8,10,11line element (vector)...........................3,7

line labels.............................................4,7map grid..............................................7,9point element (vector)........................3,7polygon element (vector)....................3,7scale bar..............................................9,11SML script layer......................................9Spatial Data Editor............................4,6,7Style Editor.............................................7Surface Modeling....................................5templates (map layout)...........................11text annotations.....................................9vector data...........................................3,4Watershed process..................................6

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Applications: Making Topographic Maps · Topographic maps produced and published by government agencies usually include both physical and cultural features, making the maps useful