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GIS Tutorial 1

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GIS TUTORIAL 1 - Basic Workbook. Data table formats. ... Microsoft SQL Server , Oracle, or PostgreSQL . unlimited size and users. GIS TUTORIAL 1 - Basic Workbook. – PowerPoint PPT presentation

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Title: GIS Tutorial 1


1
GIS Tutorial 1
  • Lecture 4
  • Geodatabases

2
Outline
  • Data types
  • Geodatabases
  • Data table joins
  • Spatial joins
  • Field calculator
  • Calculate geometry
  • ArcCatalog functions

3
Data types
  • Lecture 4

4
Directly loadable data types
  • dBase (.dbf)
  • Text with comma (.csv) or tab-separated values
    (.txt)
  • Microsoft Access (.mdb)
  • Microsoft Excel (.xls)

5
Data table formats
  • First row must have attribute names with
    self-documenting labels
  • (e.g. Pop5To17, Area)
  • Usual naming convention
  • first character is a letter
  • remaining characters be any letters, digits, or
    the underscore character
  • All additional rows of a data table need to
    contain attribute values
  • None of the rows can be sums, averages, or other
    statistics of raw data rows

6
Data table formats
  • dBase field names
  • Maximum 10 characters

7
geodatabases
  • Lecture 4

8
Geodatabase types
  • Manages features and tables inside a
  • database management system
  • File geodatabase
  • stores datasets in a folder of files
  • each dataset a file up to 1 TB in size
  • can be used across platforms
  • can be compressed and encrypted for read-only,
    secure use
  • ESRIs recommended choice

9
Geodatabase types
  • Personal geodatabase
  • stores datasets in a Microsoft Access .mdb file
  • storage sizes between 250 and 500 MB
  • limited to 2GB
  • only supported on Windows
  • ArcSDE geodatabase
  • stores datasets in a number of optional DBMSs
  • IBM DB2, IBM Informix , Microsoft SQL Server ,
    Oracle, or PostgreSQL
  • unlimited size and users

10
New file geodatabase
  • ArcCatalog

11
Import into geodatabase
Shapefile features
12
Import into geodatabase
  • Tables

13
Export from geodatabase
14
Compact geodatabases
  • File and personal geodatabases
  • Reduces size and improves performance
  • Compact personal geodatabases gt 250 MB.
  • Geodatabases with frequent data entry, deletion,
    or general editing
  • Open geodatabases in ArcMap cannot be compacted
  • remove any layers with a source table or feature
    class in that database from the TOC

15
Compress geodatabases
  • File geodatabases
  • Once compressed, a feature class or table is
    read-only and cannot be edited
  • Compression is ideally suited to mature datasets
    that do not require further editing
  • Compressed dataset can be uncompressed to return
    it to its original, read-write format

16
View geodatabases
  • Cannot identify names in Windows Explorer
  • Must use ArcCatalog

17
Data table joins
  • Lecture 4

18
Data table joins
  • Putting two tables together to make one table
  • Join two tables one-to-one by row
  • Must have the same values and data types

19
Join example
  • Housing heating fuel study for U.S. Counties
  • Source U.S. Census
  • Data table Census SF3 table for heating fuel by
    county
  • Map Features County polygons

20
Data table
  • Heating fuel table (Excel spreadsheet)

21
Data table
  • Heating fuel table data dictionary
  • H040001 Occupied housing units House heating
    fuel TOTAL Units
  • H040002 Occupied housing units House heating
    fuel Utility gas
  • H040003 Occupied housing units House heating
    fuel Bottled tank or LP gas
  • H040004 Occupied housing units House heating
    fuel Electricity
  • H040005 Occupied housing units House heating
    fuel Fuel oil kerosene etc.
  • H040006 Occupied housing units House heating
    fuel Coal or coke
  • H040007 Occupied housing units House heating
    fuel Wood
  • H040008 Occupied housing units House heating
    fuel Solar energy
  • H040009 Occupied housing units House heating
    fuel Other fuel
  • H040010 Occupied housing units House heating
    fuel No fuel used

22
Feature class
  • County polygons

23
Add data and features to map
24
Open attribute tables
  • Find common attribute to join

25
Data problem
  • FIPS has leading zero and is a TEXT field.
  • GEO_ID2 is a NUMBER fieldwith no leading zeros.

FIPS
01001
01003
01005
01007
GEO_ID2
1001
1003
1005
1007
26
Data solution
  • Make a new NUMBER field in Counties attribute
    table and use field calculator to populate new
    field from old

27
Data solution
  • New FIPS_NUM is same as GEO_ID2 and ready to join

28
Join tables
29
Join result
  • Heating fuel data is now listed for every county
    in the USCounties feature attribute table

30
Permanent joins
  • Joins are temporary and can be removed
  • Export data to make joins permanent

31
Choropleth map result
32
Spatial joins
  • Lecture 4

33
Spatial join example
  • You have census block group centroids with
    housing fuel data
  • You want to know housing fuel data by
    neighborhoods
  • No attributes in common
  • Spatial join needed

34
Spatial joins
  • Points to polygons
  • Spatially joins points (block centroids) within
    polygons (neighborhoods)
  • Joins using shape (not attribute field)

35
Spatial joins
  • Right click polygon layer (neighborhoods)

36
Join result
  • New polygon feature

37
Join result
  • Counts and sums

38
Count result
  • Number of points in each polygon

39
Sum result
  • Every block group centroid has associated data
  • (e.g. H040004, heating electricity shown in
    labels)

40
Sum result
  • One neighborhood example
  • Central business district
  • 4 block groups
  • Housing units with electricity fuel (80 299
    128 292 )
  • Sum 799

41
Choropleth map result (sum)
42
Choropleth map result (sum)
43
Other spatial joins
  • Polygons to points
  • Example ATM robberies (points) need neighborhood
    name

44
Polygon to point join result
  • Neighborhood name shows on each point

45
Other spatial joins
  • Points to points
  • Example What is the distance of a burglary to
    the nearest commercial property?

46
Point to point join result
  • Distance to nearest commercial property shows on
    each burglary point

47
Field calculator
  • Lecture 4

48
Sample functions
  • Performs numeric calculations
  • Populates field
  • Concatenates text data

49
Field calculator functions
  • Calculate acres to square miles

50
Field calculator functions
  • Populate field with county name

51
Field calculator functions
  • Concatenate house number and street fields

52
CalculatE geometry
  • Lecture 4

53
Polygon/point centroids
  • Advanced calculations for finding a polygons
    point centroid

54
Calculate XY fields
  • Add new X and Y fields in the attribute table

55
Calculate XY fields
  • Calculate geometry for X field, repeat for Y

56
XY field results
  • Results are X and Y values based on map
    properties (e.g. Long/Lat or XY feet)

57
Export XY coordinates
58
Add XY data table
59
Export as shapefile
  • XY events should be exported as permanent
    shapefile or feature class

60
Calculate area
  • Add area field and calculate geometry

61
Calculate perimeter
  • Add perimeter field and calculate script

62
Calculate length
  • Add length field and calculate script

63
Arccatalog functions
  • Lecture 4

64
Basic functions
  • Copy, paste, rename, etc.

65
View and edit properties
  • Projections, fields, etc.

66
View metadata
67
Edit metadata
68
Create new files
  • Geodatabases, tables, features, etc.

69
Summary
  • Data types
  • Geodatabases
  • Data table joins
  • Spatial joins
  • Field calculator
  • Calculate geometry
  • ArcCatalog functions
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