Introduction to GIS for Map Construction

In this lesson you will learn:

• common raster and vector data exchange formats

• sources of raster and vector data

• map construction principles

• bringing data into the GIS – the map view

• scaling and projecting the GIS map

• formatting and outputting the map – the layout view

Raster data formats

Generic raster data exchange formats:• TIFF filename.tif• JPEG filename.jpg• GIF filename.gif• BMP filename.bmp

Geographically-registered raster data exchange formats• GEOTIFF filename.tif

- with “world” file filename.tfw

Compressed raster data exchange formats• MrSID filename.sid

- with geo-reference “world” file filename.sdw

Proprietary & specialty formats• ERDAS (.lan, .gis, .img)• ESRI Grid (.grd)• Intergraph (.cot, .cit, .rle) • National Image Transfer Format (.ntf)• Uncompressed ASCII satellite image (.bsq, .bil, .bip)

Raster data sources

Types of publicly available raster data

1. map products

• scanned maps

• digital maps

2. geospatial imagery

• aerial photography

• satellite remote sensing imagery

• aerial remote sensing imagery

3. non-spatial imagery

Raster data sources – imagery

Potential sources of raster data

1. public domain data

• state-level geospatial data clearinghouses

• repository public libraries

• privately-sponsored geospatial data clearinghouses

2. fee licensed data

• source public agency (NASA, NIMA, USGS, United Nations, etc.)

• local government

• source contractor (aerial photography company, land surveyor, etc.)

3. contract data

Raster map products: 1. DRGs

Portion of a Digital Raster Graphic, USGS 1:24,000 topographic map; downloaded from the Illinois State Geospatial Data Clearinghouse

Raster map products: 2. DOQs

Lake County, IL DOQ; downloaded from the Illinois State Geospatial Data Clearinghouse

Raster map products: 3. DEMs

GTOPO30 DEM raster image of the northeastern portion of North America. Source: Land Processes Distributed Active Archive Center, USGS. http://edcdaac.usgs.gov

Raster map products: 4. LU/LC

Sample land use/land cover raster image produced by the USGS Regional Land Cover Characterization Project; derived from early 1990s 30-m Landsat Thematic Mapper data. Source: USGS, http://landcover.usgs.gov

Vector data formats

1. Generic spatial data exchange formats

• SDTS (spatial data transfer standard)

• Open GIS

2. de facto standard exchange formats

• SHP (ESRI)

• MS-Access

3. Proprietary & specialty formats

• E00 (ESRI); MAP (MapInfo); MGE (Intergraph)

• SDE (ESRI)

• Oracle Spatial

Vector map products: 1. DLGs

Sample plot of DLG data showing political boundary (white), hydrography (blue) and transportation (tan) feature classes for Dancyville, TN.

Source: USGS, http://edc.usgs.gov

Vector map products: 2. SSURGO & NWI

SSURGO soil polygons, from an portion of Marquette County, MI. Image courtesy of Michigan State University

National Wetlands Inventory data, central Lake County, IL. Map image generated by Wetlands Mapper, a product of the U.S. National Map.

Vector map products: 3. TIGER/Line® data

Railroad, road, and hydrography Tiger/Line® data, DuPage County, IL. Data courtesy of the U.S. Bureau of the Census, www.census.gov

Map construction principles

Choose:

• map geography (content)

• map scale

• datum & coordinate system

• map projection

Obtain, consistent with above:

• source material (maps, imagery, other data)

• permission to use source material

Assembling the data – the map view

Assembling the data – the map view

Map view operations

Zoom In

Zoom Out

Pan

Measure distance

Add Data

Add feature class to legend

Setting map extent and feature scales

Setting the map view projection

Formatting the map for output – the layout view

Layout elements

Layout elements

Printing the map

Sheet Size width length units

A 8.5 11 inches

B 11 17 inches

C 17 22 inches

D 22 34 inches

E 34 44 inches

A5 14.8 21 centimeters

A4 21 29.7 centimeters

A3 29.7 42 centimeters

A2 42 59.4 centimeters

A1 59.4 84.1 centimeters

A0 84.1 118.9 centimeters

Standard paper sizes

Exporting the map

What you have learned

In this lesson you learned:• Common file formats for raster data include: BMP, JPEG, GIF, TIFF, GEOTIFF, and MrSID. The world file associated with GEOTIFF or MrSID raster data provide the information necessary to geographically register the raster data.

• Common file formats for vector data include: SDTS, Open GIS, SHP, and MS-Access.

• Small- and intermediate-scale geospatial data produced by state and federal government agencies is often available through state sponsored geospatial data clearinghouses, or directly from the agency responsible for producing the data. Some of the types of raster data that are generally available, free, include: DRGs, DOQs, DEMs, and land use/land cover images. Publicly available vector data include: DLGs, SSURGO, NWI, and Tiger/Line data.

• Scale, projection, datum and coordinate system are just as critical to the choice of spatial data for GIS as they are for conventional mapping. The data used in any GIS project should either be copyright-free, or properly licensed to you for use.

• GIS maps are assembled, edited, and formatted in the map view window and cartographically rendered for final output in the layout window. The content of the layout window is dynamically linked to the map view, hence all map construction operations, including setting the projection, scale, geographic extent, and feature symbolization, are performed in the map view window.

• Maps produced in a GIS can be output to printer or plotter devices, or exported and saved as raster graphics files (BMP, JPEG, TIFF, etc.).