Chapter One
Getting Started with Digital Maps
In This Chapter
* Discovering digital maps
* Using digital maps
* Discovering types of map programs
* Understanding the differences between Geographic Information System (GIS) and consumer mapping programs
This chapter introduces you to the fundamentals of digital maps. You find out what a digital map is, the differences between static and smart digital maps, and the different types of programs available for using digital maps.
What Is a Digital Map?
Any map is a picture of where things are, generally associated with our planet and its geographic or man-made features. Road maps, hiking maps, maps to Hollywood stars, and all sorts of other maps provide a sense of place and often help you get from one place to another.
Most maps are printed on paper. That's pretty convenient. They can be folded into a lightweight, compact bundle (if you've had a little practice). Digital maps (maps made on a computer or meant to be used with a computer) serve the same purpose as their paper cousins. It's just more difficult to fold a CD.
Digital mapmaking is a significant leap forward from traditional paper maps.
This is important because of how quickly new roads, subdivisions, and development projects pop up in fast-growing urban areas. An old street map isn't much help in a new subdivision with a couple of hundred homes. The same problem affects political maps; an example is the change in national names and borders after the end of the Soviet Union.
Read on to discover the many types of digital maps.
Static map
A static map is the simplest form of digital map. Often it's a paper map that's been scanned and turned into a BMP (bitmap) or JPG (graphic) file. Aside from displaying it, printing it, and perhaps making a few edits, what you can do with the map is limited.
Static maps used to be the only type; often, a static map is all you need.
Smart map
Smart digital maps (as shown in Figure 1-1) may look like static maps, but data is associated with map locations. The data can be as basic as the latitude and longitude of a point, or as detailed about vegetation, soil type, and slope.
Spatial or geospatial data is associated with a place. The place can be smaller than a meter or as large as a country. Spatial data can be stored two ways:
TECHNICAL STUFF
TIFF (Tagged Image File Format) is a popular format for storing graphics files. The GeoTIFF extension embeds geographic tags into map images. If you view a GeoTIFF file with a standard graphics program, it looks like an ordinary map. A program that uses the data tags can access the spatial data associated with each pixel in the image.
Mapping Programs
Although many different kinds of mapping programs are available, you can classify map programs in two types: consumer programs and Geographic Information System (GIS) software. Here is a quick look at each type.
Consumer programs
A consumer mapping program is software that displays street maps, topographic maps, marine charts, or aeronautical charts. Such mapping programs are easier to use (and much less expensive) than their professional counterparts, meeting most computer users' mapping needs.
This book focuses on mapping programs available to consumers.
GIS (Geographic Information System)
A Geographic Information System (GIS) is an information system that analyzes, inputs, manipulates, outputs, retrieves, and stores spatial data. GIS is mostly used by governments; large corporations; and engineering and GIS consulting firms for land, natural resources, transportation, environmental, and urban planning and management.
TECHNICAL STUFF
Some people use the terms digital map and GIS interchangeably. This really isn't correct. GIS isn't just about making maps. GIS involves using computers and special software to help people make decisions by using spatial data.
Distinguishing between consumer mapping programs and GIS programs is important:
REMEMBER
GIS software typically has a steep learning curve; you can earn advanced degrees in GIS. Consumer mapping programs can mostly be used right out of the box and can be mastered in a relatively short period of time.
A typical consumer mapping program is a road map program that costs about $30 and provides exact routing directions to get from one location to another. This isn't a static map because it has underlying data (such as street names, distances, and gas stations), which can lead you to think it's a GIS program. Not so. A true GIS program has built-in precision tools that can (for example) let you input data about traffic flow and vehicle speeds, and then display every street where traffic volume exceeds 500 cars per hour and vehicle speeds are .5 miles an hour over the speed limit. The price tag for such a GIS program would be at least $1,000, not to mention the costs of training people to use it and gathering all the traffic data to input into the system.
TIP
Of course, if you have a burning need for high-end precision and complexity, it's still possible to get into GIS on the cheap. A growing community is developing open source and free GIS programs. Although many of these programs lack the polish of a commercial product, they do get the job done. The http:// opensourcegis.org and www.freegis.org Web sites are two excellent resources for finding out more about free GIS programs.
Using Digital Maps
There's an old song that goes, "Anything you can do, I can do better." If digital maps could sing that tune to their paper counterparts, they'd be right (for the most part). Digital mapping software offers all sorts of enhancements over paper maps, including these capabilities:
Digital maps do have a few drawbacks, including these:
TIP
If you have a laptop or personal digital assistant (PDA), you can take mapping software on the road with you.
This book helps you select and use software packages, particularly mapping programs in the free-$100 price range.
Most mapping software is readily usable, but all programs have nuances that sometimes make their features and user interfaces a little tricky.
Mapping Software: The Essentials
The first step for digital mapping is to understand the available types of mapping programs and their capabilities and limitations; that's what this part of the book is all about.
After you know what software is available, you can match it to your needs. An invitation to a birthday party may consist only of displaying a screen capture of a street map on a Web site, editing and saving the map in Paint, and then e-mailing it to friends. A week-long backpacking expedition would require a topographic mapping program (showing land features) to plan your route, view elevation profiles, and upload location data to your GPS receiver.
Before you can select the right tool for the right job, you need a general handle on the options that you can include in your digital-mapping tool chest. This section of the book organizes mapping programs into three categories:
Standalone programs
A standalone program is a program that can open and use digital maps. These programs typically don't come with map data, and you'll need to download or purchase the maps you're interested in using.
Like with a word processor or a spreadsheet, a mapping program needs someone to input data before it can be useful. In this case, the data is bits and bytes that describe how a map should be displayed. Fortunately, an amazing amount of map data is freely available on the Internet, most of it already collected by the government and in the public domain.
A big market exists for commercial map data. People buy data to use with their mapping programs because
Many standalone mapping programs aren't tied to one data type. (Chapter 2 shows which types of digital map data are commonly used.) Figure 1-2 shows a three-dimensional map of Mount St. Helens created with 3DEM from free U.S. Geological Survey (USGS) digital elevation map (DEM) data. (Mount St. Helens, an active volcano in Washington State, erupted in 1980.) The elevation map shows the crater and how the volcano blew out its side.
Map programs are viewers, editors, or both:
Usually you can't change a base map you've opened from a data file, but you can add text and draw shapes on top of the map.
Many standalone programs are either free or shareware. Two aspects of such programs are especially worth noting:
Examples of standalone mapping programs include OziExplorer (www. oziexplorer.com), USAPhotoMaps (http://jdmcox.com), and 3DEM (www.visualizationsoftware.com/3dem.html). Don't forget that you can also make maps with Paint or any other general-purpose graphics program. This book shows how to use these programs and others.
TIP
Some free, noncommercial mapping programs have advanced features that are normally more suited to professional users. Don't be intimidated by every feature and option. You can use some commands and features to make maps for your needs. And you can master those other features if you ever need to.
WARNING!
One big disadvantage to standalone mapping programs is that you need to search the Internet for the data you need, find and download it, and then open it with the map program. This process sometimes involves registering a map so that the coordinates all line up. Also, even with a high-speed Internet connection, downloading can still be a hassle. And after all that, you still have to find the map data for an area that you want to view, and then successfully load all that stuff into the mapping program.
Programs with bundled maps
Mapping companies bundle software with digital maps. The program comes with the map data and is distributed on CDs or DVDs; static or smart maps that have a lot of detail can be quite large in size. You install the mapping program, and you're immediately ready to start using the data on the CD.
Data files bundled with software are often in a proprietary file format, which can be read and used only with the software that comes with the product. The same usually holds true for maps that you can upload to a GPS receiver; only maps from the manufacturer can be used.
Sometimes you don't have much choice between using a standalone program or one bundled with maps.
Software that comes with bundled maps has gotten incredibly cheap over the years. With discounts and rebates, you can often find road atlas software for around $20 that covers the entire United States. For a little under $100, you can buy programs that come with a full set of detailed digital topographic maps for an entire state. Considering that a single paper USGS 1:24,000 map costs around $7 - and there can easily be over a thousand maps per state - that's a pretty decent value. Figure 1-3 shows a map made by Terrain Navigator (www.maptech.com/land/TerrainNavigator), which is a topographic mapping program that comes bundled with map data.
TIP
Manufacturers that sell bundled map programs (particularly those with street and road data) usually come out with a new release of their product every year or so. In addition to enhancements in the software, the map data contains new roads and updated services information (such as gas stations, restaurants, and hotels, called POIs, or Points of Interest). Whether you buy an updated copy of the software every year depends on your circumstances. If you usually travel on major roads, or in areas that haven't experienced much development and growth, you probably don't need to update every year. On the other hand, road atlas software is fairly inexpensive, so if you travel a lot and rely on the program, it can be a cheap investment.
If you have beginning to intermediate computer skills and experience, you can come up to speed quickly with bundled map programs. The user interfaces are generally simpler than those found in feature-rich, standalone programs.
Examples of programs that come bundled with maps are DeLorme's Street Atlas USA (www.delorme.com), National Geographic's TOPO! (http:// maps.nationalgeographic.com/topo), and mapping software from GPS manufacturers that interfaces with their receivers.
(Continues...)
Source: http://6minutesummary.blogspot.com/2012/01/bookdaily-genre-sampler-sports-and_31.html
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