Gis tutorial 1
This presentation is the property of its rightful owner.
Sponsored Links
1 / 65

GIS Tutorial 1 PowerPoint PPT Presentation


  • 87 Views
  • Uploaded on
  • Presentation posted in: General

GIS Tutorial 1. Lecture 5 Spatial Data. Outline. GIS coordinates Map projections Vector data formats US Census geographic files US Census data files Geospatial data sources. Lecture 5. GIS coordinates. Spherical Coordinates. Geographic Coordinate System (GCS)

Download Presentation

GIS Tutorial 1

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Gis tutorial 1

GIS Tutorial 1

Lecture 5

Spatial Data


Outline

Outline

  • GIS coordinates

  • Map projections

  • Vector data formats

  • US Census geographic files

  • US Census data files

  • Geospatial data sources

GIS TUTORIAL 1 - Basic Workbook


Gis coordinates

Lecture 5

GIS coordinates


Spherical coordinates

Spherical Coordinates

GIS TUTORIAL 1 - Basic Workbook

  • Geographic Coordinate System (GCS)

    • Angles of rotation of a radius anchored at Earth’s center

    • Latitude and longitude

    • Used by US Census, other world and federal agencies

4


Latitude and longitude

Latitude and longitude

  • longitude (prime meridian)

0

  • latitude (equator)

0

GIS TUTORIAL 1 - Basic Workbook

5


Royal observatory greenwich england

RoyalObservatory, Greenwich, England

Prime meridian

Photo courtesy of Paul Edwin Mastin, January 2011

GIS TUTORIAL 1 - Basic Workbook

6


Marco zero monument macap brazil

Marco Zero monument, Macapá, Brazil

Equator

Photo courtesy of Shan Shi

GIS TUTORIAL 1 - Basic Workbook

7


Latitude and longitude1

Latitude and longitude

Pittsburgh, PA USA

40

-80

GIS TUTORIAL 1 - Basic Workbook

Coordinates

8


Lat long coordinates

Lat/Long coordinates

GIS TUTORIAL 1 - Basic Workbook

  • Degrees, minutes, and seconds (DMS)

    • 40° 26′ 2″ N latitude

    • -80° 0′ 58″ W longitude

  • Decimal degrees (DD)

    • 1 degree = 60 minutes

    • 1 minute = 60 seconds

      40° 26′ 2″ =

      40 + (26 / 60) + (2 / 3600) =

      40 + .43333 + .00055 =

      40.434°

9


Lat long coordinates1

Lat/long coordinates

GIS TUTORIAL 1 - Basic Workbook

  • Translated to distance

    • World circumference through the poles is 24,859.82 mi, so for latitude:

      • 1° = 24,859.82 / 360 = 69.1 mi

      • 1′ = 24,859.82 / (360 * 60) = 1.15 mi

      • 1″ = 24,859.82 * 5,280 / (360 * 3,600) = 101 ft

  • Length of the equator is 24,901.55 mi

10


Gcs example census tracts

GCS example (census tracts)

GIS TUTORIAL 1 - Basic Workbook

11


Rectangular coordinates

Rectangular coordinates

GIS TUTORIAL 1 - Basic Workbook

  • UTM (universal transverse Mercator)

    • US military

  • State plane

    • Local US governments

12


Utm coordinates example

UTM coordinates example

GIS TUTORIAL 1 - Basic Workbook

  • Developed by US Army Corps of Engineers (1940s)

  • Covers world, 80°S to 80°N

  • Metric coordinates

  • 60 tuned transverse Mercator projections for longitude zones, 6° wide

13


State plane coordinates

State plane coordinates

GIS TUTORIAL 1 - Basic Workbook

Established by the US Coast and Geodetic Survey in the 1930s

All positive coordinates in feet or meters

Used by local US governments

Originally North American Datum (NAD 1927)

More recently NAD 1983 and 1983 HARN (High Accuracy Reference Network)

14


State plane zones

State plane zones

GIS TUTORIAL 1 - Basic Workbook

  • 125 zones

    • At least one for each state

    • Cannot join zones to make larger regions

    • Follow state and county boundaries

  • Each zone has its own tuned projection

    • Lambert conformal projection for zones with eastwest orientation

    • Transverse Mercator projection for zones with northsouth orientation

15


State plane zones1

State plane zones

GIS TUTORIAL 1 - Basic Workbook

16


State plane coordinates example

State plane coordinates example

GIS TUTORIAL 1 - Basic Workbook

State plane NAD 1983, Pennsylvania South, Feet

17


X y coordinate tips

X,y coordinate tips

  • US Census

  • Geographic coordinate system (GCS)

  • City of Pittsburgh

  • State plane coordinate system

GIS TUTORIAL 1 - Basic Workbook

  • Always assign coordinates according to the agency

18


X y coordinate examples

X,y coordinate examples

  • US Census

  • Geographic coordinates (GCS)

  • Block groups

  • City of Pittsburgh

  • State plane coordinates

  • Sidewalks

GIS TUTORIAL 1 - Basic Workbook

19


Map document tip

Map document tip

GIS TUTORIAL 1 - Basic Workbook

  • The first layer added in ArcMap sets the x,y coordinate system for the data frame

  • Additional layers will overlay properly as long as the correct coordinate system is assigned to feature class

    • For example, GCS to US Census files, state plane to local government files

  • Known as .prj files

20


Map document tip1

Map document tip

GIS TUTORIAL 1 - Basic Workbook

  • Example: Sidewalks added first (state plane), but block groups match even though they are in geographic coordinate system (GCS) projection.

21


Map projections

Lecture 5

Map projections


Map projections1

Map projections

GIS TUTORIAL 1 - Basic Workbook

  • Way to represent the curved surface of the earth on the flat surface of a map

  • Hundreds of map projections

  • Each map projection has advantages and disadvantages:

    • Depends on the scale of the map

    • Depends on map’s purpose

    • Different projections good for small areas, areas with a large east–west extent, or areas with a large north–south extent

23


Map projections2

Map projections

Flatten half of a rubber ball?

No. Instead, features are projected onto one of three “developable” surfaces.

Planar: a map projection resulting from the conceptual projection of the earth onto a tangent or secant plane

Cylindrical: a map projection where the earth’s surface is projected onto a tangent or secant cylinder, which is then cut lengthwise and laid flat

Conic: a map projection where the earth’s surface is projected onto a tangent or secant cone, which is then cut from apex to base and laid flat

http://www.nationalatlas.gov/articles/mapping/a_projections.html#two

GIS TUTORIAL 1 - Basic Workbook

24


Conformal projection

Conformal projection

  • Example: Mercator projection (1569)

  • used for nautical purposes (constant courses are straight lines)

GIS TUTORIAL 1 - Basic Workbook

  • Cylindrical projection

  • Parallels and meridians at right angles

  • Angles and shapes of small objects preserved (at every point, east–west scale same as north–south scale)

  • The size/shape/area of large objects distorted (scale approaches infinity at the poles)

  • Seldom used for world maps

25


Equivalent projection

Equivalent projection

  • Example: Albers Equal Area

  • standard projection for US Geological Survey, US Census Bureau

GIS TUTORIAL 1 - Basic Workbook

  • Conic projection

  • Preserves accurate area

  • Scale and shape are not preserved

26


Compromise projections

Compromise projections

  • Example:Robinson projection (1961)

  • good compromise projection for viewing entire world

  • used by Rand McNally and the National Geographic Society

GIS TUTORIAL 1 - Basic Workbook

Neither equivalent nor conformal

Meridians curve gently, avoiding extremes.

Doesn’t preserve properties, but “looks right”

27


When projection is important

When projection is important

  • Small-scale maps

    • Comparing shapes, areas, distances, or directions of map features

    • Natural appearance desired

New York

New York

Los Angeles

Los Angeles

Los Angeles

Projection: Albers Equal AreaDistance: 2,455.03 miles

Projection: MercatorDistance: 3,124.67 miles

Actual distance: 2,451 miles

GIS TUTORIAL 1 - Basic Workbook

28


When projection is not important

When projection is not important

  • Many business, policy, and management applications

  • On large-scale maps

    • Error is negligible

GIS TUTORIAL 1 - Basic Workbook

29


Vector data formats

Lecture 5

Vector data formats

GIS TUTORIAL 1 - Basic Workbook


Arcinfo coverages

ArcInfo coverages

GIS TUTORIAL 1 - Basic Workbook

Created using Esri ArcInfo software

Older format

Set of files within a folder or directory called a workspace

Files represent different types of topology or feature types


Shapefiles

Shapefiles

GIS TUTORIAL 1 - Basic Workbook

  • ArcView native format

    • Minimum files

      • .shp–stores feature geometry

      • .shx–stores index of features

      • .dbf–stores attribute data

    • Additional files

      • .prj–projection data

      • .xml–metadata

      • .sbn and .sbx–store additional indices


Cad drawings

CAD drawings

GIS TUTORIAL 1 - Basic Workbook

  • CAD software

    • Autodesk, AutoCAD (.dwg)

    • Bentley, Microstation (.dgn, .dxf)

  • Often used by engineering companies

  • Better digitizing precision


Cad drawings1

CAD drawings

GIS TUTORIAL 1 - Basic Workbook


Us census geographic files

Lecture 5

US Census geographic files


Census tiger line files

Census TIGER/Line files

GIS TUTORIAL 1 - Basic Workbook

  • http://www.census.gov/geo/www/tiger/

  • Topologically Integrated Geographic Encoding and Referencing files

    • US Census Bureau product for digital mapping of the United States

    • TIGER maps available for the entire United States and its possessions, including roads and streets, railroads, rivers, lakes, political boundaries, and census statistical boundaries

36


Example census geographies

Example census geographies

GIS TUTORIAL 1 - Basic Workbook

37


Tiger census tracts

TIGER census tracts

GIS TUTORIAL 1 - Basic Workbook

Between 1,000 and 8,000 people (in general)

1,700 housing units or 4,000 people

Homogeneous population characteristics (economic status and living conditions)

Normally follow visible features

May follow governmental unit boundaries and other invisible features


State tracts 2010

State tracts (2010)

GIS TUTORIAL 1 - Basic Workbook


County tracts 2000 and 2010

County tracts (2000 and 2010)

GIS TUTORIAL 1 - Basic Workbook


City tracts 2000 and 2010

City tracts (2000 and 2010)

GIS TUTORIAL 1 - Basic Workbook


City block groups 2000 and 2010

City block groups (2000 and 2010)

  • Subdivisions of a census tract

  • 400 housing units, with a min. of 250 and a max. of 550

  • Follow clearly visible features (roads, rivers, and railroads)

GIS TUTORIAL 1 - Basic Workbook


Census blocks

Census blocks

  • Smallest geographic areas for which the Census Bureau collects and tabulates decennial census information

  • Block boundaries visible (street, road, stream, shoreline, etc.) or invisible (county line, city limit, property line, etc.)

GIS TUTORIAL 1 - Basic Workbook


Us census data files

Lecture 5

US Census data files


Decennial census data

Decennial census data

GIS TUTORIAL 1 - Basic Workbook

  • Years 2000 and 2010

    • Summary File 1 (SF 1)

      • Short form, entire population

      • Population

      • Age

      • Sex

      • Race

      • Families

      • Households

      • Housing units

    • Tracts, block groups, blocks


Decennial census data1

Decennial census data

GIS TUTORIAL 1 - Basic Workbook

  • Year 2000 Summary File 3 (SF 3)

    • Long form, 1 in 6 households, random

    • Income, poverty

    • Educational attainment

    • Citizenship

    • Employment, workplace, disability

    • Transportation, travel time to work

    • Detailed housing attributes, housing value, residency five years previous

    • Languages spoken, ancestry

  • Tracts, block groups, NOT blocks


American community survey acs

Replaces long-form questionnaire and SF3 data

Randomly selects about 3 million addresses each year to participate

Has rolling, 1-, 3-, and 5-year estimates and 90% confidence intervals

Add and subtract Margin of Error (MOE) to/from Estimate to get the confidence interval

American Community Survey (ACS)

GIS TUTORIAL 1 - Basic Workbook

47


Acs data

Age

Sex

Race

Family and relationships

Income and benefits

Health insurance

Education

Veteran status

Disabilities

Where you work and how you get there

Where you live and how much you pay for certain essentials

ACS Data

GIS TUTORIAL 1 - Basic Workbook


Acs 1 year estimates

ACS 1-year estimates

GIS TUTORIAL 1 - Basic Workbook

Most current

Data with populations 65,000+

Smallest sample size

Less reliable than 3–5 year

Best used when currency is more important than precision, or when analyzing large populations

Not available for tracts or block groups


Acs 3 year estimates

ACS 3-year estimates

GIS TUTORIAL 1 - Basic Workbook

  • Data with populations 20,000+

  • Larger sample size than 1-year

  • More reliable than 1-year but less reliable than 5-year

  • Best used when analyzing smaller populations or geographies not available for 1-year estimates

  • Not available for tracts or block groups


Acs 5 year estimates

ACS 5-year estimates

GIS TUTORIAL 1 - Basic Workbook

  • Data for all areas (tracts and block groups)

  • Largest sample size

  • Most reliable but least current

  • Best used when analyzing small populations, or when precision is more important than currency

  • 2005–2009, 2006–2010, etc.

    • Note: 2006–2010 only available for county, city, town, place, American Indian Area, Alaska Native Area, Hawaiian Home Land, and tracts. Block group estimates are available only in the ACS Summary File.


Downloading block group data

Downloading block group data

GIS TUTORIAL 1 - Basic Workbook

http://www.census.gov/acs/www/data_documentation/summary_file/

Find the tables of interest and their sequence number in the "Sequenced Number and Table Number" spreadsheet (http://www2.census.gov/ acs2010_5yr/summaryfile/)

Download the sequences that contain those tables


Other census data

Other census data

GIS TUTORIAL 1 - Basic Workbook

  • Economic census

  • Population estimates

  • Annual economic surveys

  • DataFerret

    • http://dataferrett.census.gov/


Geospatial data sources

Lecture 5

Geospatial data sources


Spatial data infrastructure

Spatial data infrastructure

GIS TUTORIAL 1 - Basic Workbook

  • Federal Geographic Data Committee (FGDC)

    • This nationwide data publishing effort known as National Spatial Data Infrastructure (NSDI).

    • Established by presidential order

    • Responsible for standards, policies, web portals

    • FGDC activities are administered through the FGDC Secretariat, hosted by the US Geological Survey


Spatial data packaging

Spatial data packaging

GIS TUTORIAL 1 - Basic Workbook

  • Metadata

    • Documentation enabling intelligent use and interpretation

  • Data contents

    • Provided by geographic area (political, statistical, tile) or seamlessly (with extraction by area)

    • Quality of geographic features

      • Vector maps are generalized for small-scale maps

      • Raster maps vary by pixel size (30m to a few inches) and color depth 8 bits to 24 bits per pixel

    • Coordinate system

    • File format

    • Download or web service


Gis tutorial 1

Classification of map layers

GIS TUTORIAL 1 - Basic Workbook

  • Earth as a system

    • Living things are on, under, or above the Earth’s surface

    • They depend on the Earth and its environment for life and well-being

    • They are organized in political, social, territorial, and other arrangements

  • Map layers

    • Physical features:

      • Earth’s surface and subsurface

    • Environmental features:

      • atmosphere, climate, and weather

    • Living thing populations:

      • people, animals, plants, and microbes

    • Organizational features:

      • political, legal, administrative, and ecosystem


National map orthoimagery

National Map orthoimagery

GIS TUTORIAL 1 - Basic Workbook

  • http://nationalmap.gov/viewer.html

  • Replacing the digital orthophoto quadrangles

    • High-resolution, seamless images in UTM coordinates

    • Rectified to remove distortions

    • 1m resolution with 0.5 m or 1 ft in urban areas, natural color


National elevation data ned

National Elevation Data (NED)

Hillshade NED map for Rockville, MD

GIS TUTORIAL 1 - Basic Workbook

  • http://ned.usgs.gov/

    • Replaces the digital elevation model (DEM)

    • Seamless raster map with 30m resolution for nation and 10m or better in some areas


Land cover

Land cover

GIS TUTORIAL 1 - Basic Workbook

  • http://nationalmap.gov/viewer.html/

    • Natural and man-made surface features

    • Collected from satellites in 1992, 2001, and 2006


National hydrography dataset

National Hydrography Dataset

GIS TUTORIAL 1 - Basic Workbook

  • http://nhd.usgs.gov/

    • Water bodies, lines, and points

    • Identifies segments (reaches) with network coding (flow and direction)


Usgs national water datasets

USGS national water datasets

GIS TUTORIAL 1 - Basic Workbook

  • http://waterdata.usgs.gov/nwis/rt

    • Streamflow conditions

    • 5,000 stream gages with telemetry transmits depth

    • Program estimates flow rate


Example geospatial sources

Example geospatial sources

GIS TUTORIAL 1 - Basic Workbook

  • Government websites (examples)

    • http://data.gov/

    • http://www.geoplatform.gov/home/

    • http://nationalatlas.gov/

    • http://nces.ed.gov/ccd/ - National Center for Education Statistics

  • Universities

  • State clearinghouses

  • Local GIS departments

  • Libraries

    • For example, online business databases


Example geospatial sources1

Example geospatial sources

GIS TUTORIAL 1 - Basic Workbook

  • Commercial resources

    • (Esri, Google, engineering companies, etc.)

  • Historic GIS websites

    • http://www.nhgis.org/

    • http://www.aag.org/cs/projects_and_programs/historical_gis_clearinghouse

    • http://peoplemaps.esri.com/pittviewer/


Summary

Summary

  • GIS coordinates

  • Map projections

  • Vector data formats

  • US Census geographic files

  • US Census data files

  • Geospatial data sources

GIS TUTORIAL 1 - Basic Workbook


  • Login