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.