Transcript Document

Extra Materials
Introduction to ArcWorkstation
What’s it look like?
Traditionally a UNIX based “command line interface”
package…
 Ran on UNIX machines.
 You typed in commands, and it showed you the results in
another simple window.
What’s ArcWorkstation made up of?
 Made up of separate modules that communicate with each
other. The command line interface is…
Arc: core application for doing analysis, and using
“workspaces” where all the files are kept for each
project.
ArcEdit: for editing maps interactively.
ArcPlot: for neat plotting of maps.
ArcTools: Pre-made AML scripts
Grid: for working with image files/raster
data.
(Might also see on older systems: ArcTIN: 3D work; ArcPress:
printing; ArcStorm: multiuser databases; ArcNetwork: networks).
What is ArcWorkstation?
 You can think of it as two main bits…
ARC – the starting program where most stuff is done.
INFO – a database, which holds tables of related
information, all tagged with a geographical location.
Lets you analyse the database data using a map interface,
and display the results as a map.
Shape
Data
Point
Me
Polygon
House
Line
Fence
Polygon
Pub
Why bother with it?
 Because:
ArcGIS 8/9.x doesn’t have the functionality of
ArcWorkstation, and plenty of places still use it.
There is still a lot of use of legacy AML code.
There is still a lot of data floating around in Coverages.
 We’ll teach you enough to understand how it works and
give you a foundation to work from if you come across it.
The ArcInfo Data Model
 Store all the same types of features in one file
using x,y coordinates…
i.e. all the point features in one file, all the line
features in another file, and all the associated nonlocation data in yet another file.
 Makes storage and handling easier.
 Makes analysis easier.
 The filenames show what kind of data they
hold.
e.g. Label Points are stored in a LAB (lab.adf) file.
Storing Data
Storing Vector data
 The files hold coordinate data and Feature
Numbers that are assigned sequentially to
Features in the file.
Feature Number
Coordinates
#1
0,0 10,10
#2
10,10 10,0
#3
0,0 10,0
Tics
 Tics – geographical control points used to register
(overlap) different datasets, and transform (eg. put in a
new projection scheme) the data.
 For example, you might mark in known locations on two
datasets, usually at the data edges, as Tics.
 Stored in a TIC file (tic.adf).
Arcs
 Arcs - stored in an ARC file (arc.adf).
 A point where an Arc changes direction is
called a “Vertex”.
 The start and ends of Arcs, and the crossing
point between two Arcs, are called “Nodes”.
 The ARC file stores each Vertex and Node as
an x,y coordinate.
Data can be assigned
to Nodes
Polygons
 An area - can also have “islands” inside, that
cut out inner areas.
+42
 Made from one (or more) Arcs.
 The end Node is the same as the starting
one.
 Each also has a Label Point (x,y) associated
with it, stored in a LAB file.
Polygon-Arc List
 The Polygon-Arc List file (pal.adf) stores which
Arcs make up each Polygon. That way we don’t
need to store the Arc coordinates again.
ARC
PAL
Feature
Number
Arcs
23
#1,#2,#3
#1
#2
+23
#3
Feature
Number
X,Y
#1
0,0 10,10
#2
10,10 10,0
#3
0,0 10,0
Polygon-Arc List
 The outside or “Universe” Polygon is always
feature number 1, ie. first in the PAL file.
 Islands start with a zero, followed by the Arcs.
Topology
 Analysis we might want to do…
“How do I move from Arc to Arc to get from A to B
fastest?”
“If I leave Polygon A going north, which Polygon do I
enter?”
 To do these analyses we need some notion of
Topology, ie. the spatial relationships between
features.
Topology in ArcInfo
 Three ways topology is defined in ArcInfo…
Arcs connect at Nodes.
Arcs have direction, and therefore a left and right
side.
Arcs that connect to surround an area make a
Polygon.
How Topology is stored
Stored in the files.
Note that polygons are listed
clockwise in the PAL, with minus
figures for reverse direction Arcs.
N2
N1
PAL
+23
N3
Feature
Number
Arcs
1
Outside Arcs
23
#1,#2,-#3
ARC/ATT
Feature
Number
X,Y
From
Node
To
Node
Left
Polygon
Right
Polygon
#1
0,0 10,10
N1
N2
1
23
#2
10,10 10,0
N2
N3
1
23
#3
10,0 0,0
N1
N3
23
1
Feature Attributes
 Info stores information about each feature in a Feature
Attribute Table using the Feature Number to match the
attribute data to the coordinates in the other files in a
one-to-one relationship. Each data type has its own table
type.
 Each feature will also have a unique User Defined ID
kept in its table in addition to its Feature Number.
PAL
FAT
Arc
Feature
Numbers
Polygon
Feature
Number
Polygon
Feature
Number
User
Defined
ID
Type
Use
#1,#2,#3
23
23
44
Park
Public
#111,#154,#16
24
24
56
Garden
Domestic
#22,#34,#17
42
42
47
Pond
Public
Types of Feature Attribute Table
 Label Points / Polygons – Point/Polygon Attribute
Table (PAT / pat.adf file).
Includes AREA and PERIMETER columns with the values
associated with any Polygons for which the Points are
labels.
Can be used to hold points or Polygon labels, but not both.
 Arcs – Arc Attribute Table (ATT / att.adf file).
Includes FNODE#, TNODE#, LPOLY#, RPOLY#,
LENGTH columns.
 When Nodes have data associated with them Node Attribute Table (NAT / nat.adf file).
Includes an ARC# column referencing one of the Arcs.
Feature Attribute Table Format
 After the columns listed above usually come
the Feature Number (NAME#) and the User
Defined ID (NAME-ID) columns.
 Following these, users can then create more
columns to hold attribute data.
Example PAT
 Note that the Universe Polygon is first, and
the AREA given for it is the negative total of
the rest.
AREA
PERIMETER
SOILS#
SOILS-ID
-2021474.264
8606.065
1
0
1186954.500
6134.177
2
43
Water
92.042
3
1
Id3
7345.473
4
2
Sg
10962.990
492.525
5
3
Id3
14700.509
468.122
6
4
Id3
18515.934
589.712
7
5
Ns1
369.352
393753.469
SOIL-CODE
Other Vector data
 Region – several related Polygons, nested or
overlapping. Stored in a PAT.regionName (pat.adf file).
 Annotation – text drawn along an associated feature.
Stored in a T(ext)AT (txt.adf file).
 Section – an Arc / portion of Arc representing a part of a
pathway. Stored in a SEC table (sec.adf file).
 Route – a pathway made out of multiple Sections.
Stored in a R(oute)AT (rat.adf file).
Putting features together
 So, we’ve seen that individual
features are stored in files with similar
types (eg. all the line features in a file
of Arcs).
 When these are combined, you get a
data “Coverage”. A Coverage usually
contains one type of geographical
information or analysis result, eg.
“Geology”, “Roads”, or “Quickest
routes”
 Several Coverages may go together
in a map, and you can turn different
ones on and off to display different
facets of a map.
Coverages
 In the file system, these are represented as
the directories your data files go in.
 They let you keep data files together and
display them at the same time.
 Usually it is the name of the Coverage that
goes to form the Feature Number and ID
column names.
Eg. The SOILS coverage before gave our example
PAT a SOILS# Feature Number column and a
SOILS-ID column.
Addition Coverage information
 As well as our data files, a Coverage will have
several other pieces of information associated
with it.
A Coverage Extent (BND / bnd.adf file) - this records the
upper right and lower left corners of a rectangle containing
all the feature data in the Coverage. It need not contain all
the Tic and Annotation points.
A Coordinate Definition file (PRJ / prj.adf ) - holds the
Coverage’s map projection information
A Tolerances file (TOL / tol.adf ) - holds a number of
processing tolerances, eg. How close Tics in different files
need to be before they count as matching.
Putting Coverages together
 Finally Coverages can be kept together in project areas
called “Workspaces”.
 Workspaces allow you to keep all the data and Coverages
you generate for a project in one place, separate from any
other work you may be doing.
 In the file system they’re represented as directories which
include all the Coverage directories you’re working on in a
project.
 One of the first things you do on starting any
ArcWorkstation project is move to your present
Workspace.
The Vector Data Model
Different views of the same data.
File system
ArcCatalog
Workspace
Coverages
Vector data
Raster data
TIN data
Summary
 Vector data includes Label Points, Arcs, Polygons
and Tics.
 The coordinates for the features of each type are
stored in separate files, one file for each type.
 Within the files, each individual feature has a Feature
Number and a set of coordinates.
 The Feature Number is used to link features to
attribute data stored in a Feature Attribute Table of a
particular type.
 You can get at the combined data through their
representation as Tables in ArcWorkstation.
Summary
 Data stored in separate files / tables can be
combined to form Coverages.
 Coverages usually contain information about
a single landuse or analysis result.
 All the Coverages in a project can be kept
together in a Workspace.
 Coverages and Workspaces are represented
as directories in the file system.
ArcCatalog
 It is vital that you never alter the file names or
location outside of the ArcGIS applications.
 You can get at most of the information in the
files and change/move/delete them in ArcGIS.
 The best way to do these operations is in
ArcCatalog.
 We looked at some of the functions of
ArcCatalog in the last practical. We’ll add a bit
more detail now.
Navigating
 ArcCatalog starts up
displaying your
harddrive, but you can
add additional drives.
 You can add online
databases if they hold
appropriate data.
 Databases are a whole
other course! Check
ArcCatalog Help files for
more details!
Data viewing
 Can view Coverages in a number of ways.
Metadata
 “Data about Data”.
 Where it’s from and what’s happened to it.
 Who made it and what’s its problems.
 What does it contain, and how.
 ArcCatalog lets you see and change metadata for…
 Describing the data and where it’s from.
 Describing the spatial data form and projection etc.
 Describing the attributes associated with the data.
 Double-click on a metadata element to open up the
metadata form.
 The metadata is in the Coverage’s metadata.xml file.
 XML is a markup language like HTML. You can open it in
Internet Explorer if you want to see what it looks like.
Altering and copying Coverages
 You can use ArcCatalog as if it were Windows Explorer
to rename, delete, copy or move Coverages and other
data items, and make new folders.
 You use exactly the same keys/menus as you would in
Explorer. Most menu options can be got at by rightclicking on a folder or file.
 The only difference is that ArcCatalog simultaneously
goes through and updates all the files ArcGIS needs to
keep track of what’s happened to the data.
Making a Workspace
 Making a new Workspace is as easy as making
a new folder.
 File > New > ArcInfo Workspace
(or right-click > New > ArcInfo Workspace)
 Rename the Workspace appropriately.
 If you look in Explorer, you’ll see an Info
directory has been made in the Workspace
directory to store related information.
Making a Coverage
 Making a Coverage is almost as easy, but
requires slightly more thought.
 File > New > Coverage…
 This brings up a “Wizard” (set of instructional
forms to fill in) to help you.
Name the Coverage
 You can use an existing coverage to supply
boundary, tic and projection information.
Fix the projection
 If you don’t supply a template, you’ll need to
say what projection scheme it’s in, or pick
none.
Generate initial topology
 If you know which feature type will be
important, you can generate the appropriate
feature table.
Other ways of manipulating files
and Workspaces
 Command line from Arc
(the web version of this
lecture has equivalent
notes for
ArcWorkstation).
 Using any of the
ArcTools.
 ArcTools is a set of AML routines
with menus for doing tricky Arc tasks.
Summary
 Never alter the files or directories outside of
ArcGIS.
 The easiest way to alter, delete or move
ArcGIS data is with ArcCatalog. It acts like
Explorer, but informs Arc what it’s doing.
 You can manipulate data and directories using
Arc or ArcTools.
Cleaning in ArcCatalog
 Right-click on the Coverage > Properties
 General > clean
Fuzzy Tolerance
 Fuzzy Tolerance : the distance up to which points will be
considered the same and snapped to the same point.
 This helps eliminate slithers.
 Should be small (~1/100,000 BDN rectangle size). If too
small an automatic value is given (see ArcDocs).
x1
X 200
X 200
uncleaned
cleaned
Dangles
 Dangle Length : any overshooting Arc longer than this
won’t be removed as an error.
 Usually zero for Arc Coverages, 0.05 inches (0.127 cm)
for Polygons.
 Note that Tolerances can be set in the Coverage
properties before this time (sets the TOL Table / file).
x1
X 200
X 200
uncleaned
cleaned
Building in ArcCatalog
 After cleaning, hit the build button to build the Topology.
 At this point you can decide what Topology to build.
 Just because you digitised as Polygons doesn’t mean you
can’t make a set of Arcs or Nodes here for your Coverage.
The Polygons will be split or Nodes extracted as
appropriate.
Building in ArcCatalog
 Once you have your new Features (Arcs from
Polygons, for example) you can go back into
ArcMap and edit / delete bits using the Editor
Select tool.
Editing - ArcEdit
 By and large, not much point in using it now.
 However, there are a few useful commands if
you can seem to clean/build your topologies.
 nodeerrors
Lists Arc undershoots, overshoots and open Polygons.
 labelerrors
Lists where Polygons are associated with multiple
labels. This should only be a problem if importing a
Coverage previously produced in ArcWorkstation.
Error marks
 Errors are marked at the Nodes where there’s a problem.
Note that pseudo-Nodes (Arc crosses or Arcs join to
themselves) show as diamonds. These are ok, except
where they show a missing Arc i.e. two labels in one
Polygon.
Overshoot
Overshoot
Undershoot
Open Polygon
Missing Arc
Exporting
 The same ArcToolbox conversion tools let you
export Coverages as different formats. Also the Arc
export command.
 Should always clean and build before exporting.
 Supported formats include…
“Generate” (.gen) ASCII files.
Interchange “e-naught-naught” (.e00) files – a popular way
of transfering ArcGIS Coverages – esp. UNIX to NT and
vice versa. Includes all the information necessary.
Data manipulation
Coverage Feature Attribute Tables
 Info stores information about each feature in a
Feature Attribute Table using the Feature Number
to match the attribute data to the coordinates in the
geography files in a one-to-one relationship. Each
data type has its own table type.
PAL
FAT
Arc
Feature
Numbers
Polygon
Feature
Number
Polygon
Feature
Number
User
Defined
ID
Type
Use
#1,#2,#3
23
23
44
Park
Public
#111,#154,#16
24
24
56
Garden
Domestic
#22,#34,#17
42
42
47
Pond
Public
Types of Feature Attribute Table
Label Points – Point/Polygon Attribute Table
(PAT / pat.adf file).
Includes AREA and PERIMETER columns with
the values associated with any Polygons for which
the Points are labels.
Arcs – Arc Attribute Table (ATT / att.adf file).
Includes FNODE#, TNODE#, LPOLY#, RPOLY#,
LENGTH columns.
Example PAT
Note that this Table has an extra, nonstandard column in it “SOIL-CODE”.
AREA
PERIMETER
SOILS#
SOILS-ID
-2021474.264
8606.065
1
0
1186954.500
6134.177
2
43
Water
92.042
3
1
Id3
7345.473
4
2
Sg
10962.990
492.525
5
3
Id3
14700.509
468.122
6
4
Id3
18515.934
589.712
7
5
Ns1
369.352
393753.469
SOIL-CODE
Joins
 You can produce data tables that float free from
the FATs.
 If these have one column data in them that is…
Unique: i.e. is different for each record.
Also present in a FAT.
 …you can JOIN the Tables, that is, copy all or
some of the data out of the free-floating table and
into the FAT.
1
X
P
1 A C X
2
Y
Q
2 A D Y
3
Z
R
Data
3 B D Z
1
A C
2
A D
3
B D
FAT
New FAT
Tables in ArcMap
Selection
Editing
Table Calculations in ArcWorkstation
In INFO use the CALC command.
Select Table / Records to act on.
Issue CALC command.
Results can only be numeric.
Can use other columns, e.g…
CALCULATE ANNUAL_WAGE = MONTHLY * 12
For non-numeric you need an AML or Java
routine.
Table Relates
 INFO is a relational database: one Table item
can be linked to multiple items in other Tables.
 Types of Relate
 Relates in Coverages
 Relation Objects in Geodatabases
Table Relates
 This is done without adding the data to the Table,
therefore storage space lower than a Join. Also
means a group of people can access one large
geography file, but connect different data to it.
 Usual to link a Feature Attribute Table (FAT) to an
external data table.
 E.g. link a country geography to Tables of
population, domestic products, etc.
Table Joins
 The relationship between items in a join must be
one-to-one.
 If not, JOIN will take the first value it comes across.
FAT
External Table
Resulting Join Table
SITE#
SITE
#
SITES
-ID
SITESID
MONTH
RAINFA
LL
SITESID
MONTH
RAINFA
LL
1
22
22
JAN
220
1
22
JAN
220
2
31
22
FEB
310
2
31
JAN
510
3
14
22
MAR
140
4
51
31
JAN
510
Table Relates
 Relates can store one-to-many relationships and
they can be used in analysis.
 E.g. Show all SITES where at least one month has
> 300mm RAINFALL and show the MONTH.
FAT
External Table
MONTH
Result
SITE
#
SITES
-ID
SITESID
RAIN
FALL
SITE#
SITESID
MONTH
1
22
22
JAN
220
1
22
FEB
2
31
22
FEB
310
2
31
JAN
3
14
22
MAR
140
4
51
31
JAN
510
 Again, there must be an identically named column
in each, holding the data used to link the Tables.
ArcWorkstation vs. ArcGIS
 Note: ArcWorkstation can do many-to-one, but not
one-to-many. ArcDesktop can do both.
SITE
#
SOILTYPE
1
A
2
SOILTYPE
SAND
CLAY
A
30
30
B
B
20
60
3
B
C
40
20
4
A
D
30
50
SITE
#
SITES
-ID
SITESID
1
22
22
JAN
220
2
31
22
FEB
310
3
14
22
MAR
140
4
51
31
JAN
510
MONTH
RAINFA
LL
Many-to-one
One-to-many
Coverage Relate Arc commands
 relate add
Interactively or in one go, add a relate. You can
have up to 100 at a time before you have to
redefine one.
 relate drop
Remove a relate.
 relate save name
Saves a current set of relates to a file.
 relate restore name
Gets saved relates.
 relate list
Lists current relates.
Interfaces
ArcToolbox, ArcTools, Arc
Parts of a relate
 Relation name: arbitrary name <= 8 letters.
 Table Identifier: name of the Table – usually not a
Feature Attribute Table (FAT).
 Database: usually INFO. Note that you don’t
specify a table – the relate works on any table with
the right column – usually a FAT.
 Info Item: the column in the INFO FATs.
 Relate column: column in the non-FAT table
 Relate Type: how the Tables are linked.
 Relate access: rw (read-write), ro (read only) or
auto (same as the FAT).
Types of relate
 This is determined by the sorting in the Tables.
 Linear : no sorting – slow unless the FAT and
external table are sorted, in which case fast.
 Ordered : related non-FAT table must be sorted
by the values in the Relate column.
 Link : relate by Feature ID. Shouldn’t be used, as
the system can change IDs without warning,
making the relate outdated.
 Table: same conditions as ordered – but if an
absolute match is missing the record in the related
table with the next highest value is taken.
 First: only option if you are not working with
INFO.
Interfaces
ArcToolbox, ArcTools, Arc
Parts of a relate
 Relation name: arbitrary name <= 8 letters.
 Table Identifier: name of the Table – usually not a
Feature Attribute Table (FAT).
 Database: usually INFO. Note that you don’t
specify a table – the relate works on any table with
the right column – usually a FAT.
 Info Item: the column in the INFO FATs.
 Relate column: column in the non-FAT table
 Relate Type: how the Tables are linked.
 Relate access: rw (read-write), ro (read only) or
auto (same as the FAT).
Types of relate
 This is determined by the sorting in the Tables.
 Linear : no sorting – slow unless the FAT and
external table are sorted, in which case fast.
 Ordered : related non-FAT table must be sorted
by the values in the Relate column.
 Link : relate by Feature ID. Shouldn’t be used, as
the system can change IDs without warning,
making the relate outdated.
 Table: same conditions as ordered – but if an
absolute match is missing the record in the related
table with the next highest value is taken.
 First: only option if you are not working with
INFO.
Arc Commands
 All ArcToolbox tools have equivalent Arc
commands.
 Consult the ArcDocs command list under the tool
names.
 Most also have easy to use interfaces under
ArcTool’s Command Tools.
Analysis in ArcWorkstation
 Geodatabases don’t exist.
 Equivalent is a Network Coverage which is used
in ArcPlot.
 The Netcover command creates a Network
Coverage and opens the command interface for
issuing other network commands.
ArcWorkstation Network functionality
 Finding minimum-cost paths
 Allocating supply and demand
 Gravity modeling
 Location-allocation modeling
 Building a distance matrix
 Determining connectivity
 Assigning turn impedances
 Ordering features
 Classifying features
 Listing travel directions
Programming ArcWorkstation
Please see the extra materials on AML.