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
• JPEG
• GIF
• BMP
filename.tif
filename.jpg
filename.gif
filename.bmp
Geographically-registered raster data exchange formats
• GEOTIFF
filename.tif
- with “world” file
filename.tfw
Compressed raster data exchange formats
• MrSID
- with geo-reference “world” file
filename.sid
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
Add Data
Measure distance
Pan
Zoom Out
Zoom In
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
Standard paper sizes
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
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.).