Exercise 3 – UML modelling in ArcGIS

AG2411 GIS Architecture
Period 2, 2008
Dr. Mats Dunkars / Prof. Yifang Ban
First created: 2006-08-22 / Mats Dunkars, Urška Demšar
Last updated: 2007-10-09 / Xing Lin
Exercise 3 – UML modelling in ArcGIS
Introduction
During this exercise we will create a model in Visio that will be imported into the GIS
software ArcGIS. In the previous exercise the modelling was focused on the creation of an
application. In this exercise we will model a geographical database.
In case you are need familiar with ArcGIS. Please refer to the Exercise 1: Introduction to
ArcGIS of course Visualization Techniques to gain a basic knowledge of ArcGIS first. You
can find the related document by following the link below:
http://www.infra.kth.se/courses/AG2412/E1A.pdf
Requirements
To pass the exercise you should present a successfully implemented geographical database in
ArcGIS to the exercise supervisor and submit the pdf-exported map showing this database.
Task
You will create a large-scale geographical database that can be used for local spatial planning.
It should contain the following information
• Parcels with information about parcel-number and owner.
• Buildings with information about addresses, owner and usage.
• Roads with information about need for maintenance.
• City blocks that have information about population statistics. A city block consists of
1..n parcels
• Schools with information about number of pupils, school type, etc.
• Various information that is used as background such as parks, fences, playgrounds
etc.
Create the UML model of the database in such a way that it has the following:
• Classes with different geometry types
• Associations between classes
• Attributes
You do not have to create any operations in this model.
Connecting Visio and ArcGIS
To create a UML model that can be imported into ArcGIS you need to start Visio with a
template. These can be found in C:\Program Files\ArcGIS\CaseTools\UmlModels.
Double click on the template called ArcInfo UML model Visio 2003. As Visio starts you will
be asked whether the Macros in the template should be activated. Chose to enable the macros.
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You may also get a window saying something like: the security level is high and macros are
not enabled. If this happens choose Tools – Macros – Security. Change the security level to
low and then restart Visio from the ArcGIS template in the manner described above.
When Visio has started you can look in the Model Explorer. Here you can find a new folder
called ArcInfo Uml Model. In this folder you find other folders that contain classes and
interfaces from the ArcGIS data model. These classes are used to get your own model
connected to the ArcGIS data model. Further down you can also find a folder that contains
types that have been defined in the ArcGIS data model.
To create your own class diagram you start by adding a package under Workspace and then
adding a new Static structure diagram in this package in the same way as we did in the
previous exercise.
You connect to the ArcGIS data model by inheriting the functionality from one of the ESRI
object classes. Here we will only consider two classes: “Feature” and “Object”. Object is a
class with no geometry while “Feature” is a class that has geometry. A class that should have
geometry should inherit from the “Feature” class and a class without geometry inherit from
“Object”. Both classes can be found in the Model Explorer under ArcInfo Uml Model –
Logical View – ESRI Classes.
To create an object class for buildings you first drag and drop the class “Feature” onto the
diagram. Then you add your own new class for “Building” and a generalisation between the
two classes to make sure that “Building” inherit the characteristics of “Feature”.
To set the type of an attribute you have to use the data types provided by ESRI. For instance,
to set the data type of the Attribute “owner” on the “Building” class you choose the type
“esriFieldTypeString” rather than the ordinary string type.
The “Feature” class contains a geometry but it is not defined which kind of geometry. This
has to be defined as a “Tagged value” on the object class. This is what you are supposed to
do:
• Open the class window for class “Building”
• Choose the category “Tagged values”
• Press the New button and call the new value “GeometryType”
• Set the Value of “GeometryType”. You can choose between:
“esriGeometryPolygon”, “esriGeometryPoint” and “esriGeometryPolyline”.
When you build your model, do not forget to occasionally save your work as the XML
drawing file!
Exporting and checking the model
Importing the model into ArcGIS consist of three steps:
1. exporting from Visio to an XML-file.
2. Running a semantics check on this file in Visio
3. Importing the XML-file to ArcCatalog
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As you develop your model it is a good idea to perform the two first steps regularly to find
errors. These two steps are described here while the last step is described towards the end of
the exercise.
To be able to export your model as a XML file (attention, this is NOT the same as saving it as
XML drawing file, which you have been doing so far), do the following: first save your
model, so you don’t lose it. Then go to Tools – Options – Advances – File Paths. In Add-ons
add the following path:
C:\Program Files\Microsoft Office\Visio11\1033
Close Visio and restart it from ArcGIS template (as before). Open the XML drawing file that
contains your model.
For correct export to a XML file you need to have a file named uml.dtd located in the folder
where you will store your XML file. This file can be empty. Make sure you have such a file in
the directory where you intend to store your XML file. You can for example copy the uml.dtd
file from the folder C:\Program Files\ArcGIS\CaseTools\Utilities to your directory at Z: disk.
To export your model as a XML file you point at Tools – Add-Ons – ESRI XMI Export in
Visio. Give the XML file a proper name.
To perform the semantic check you choose Tools – Macros – ESRI – Semantics_checker. A
window pops up where you can specify the file that is going to be checked. Browse to find the
file created in the previous step. You should also mark that that you are going to check an
XMI file. Finally you press “Check” and hopefully there are no errors.
To create a binary association you have to create an attribute where you can store the identity
that is used for linking. For instance, to create an association between “buildings” and
“parcels” where one parcel can be associated with zero to many buildings you first define an
attribute in the “building” object class. Call this attribute “ParcelID” and give it the type
“esriFieldTypeInteger”. In the table that will contain the attributes for object class “building”
there will be one column called “ParcelID”. Here the object identity of the parcel that a
particular “building” belongs to, will be stored.
Next you create the binary association. As you drag and drop the association onto the diagram
you can see that the endpoints are given numbers, i.e. “end3” and “end4”. The part of the
association that has the lower number should be set to point to the “Origin class” and the other
end should point at the “Foreign class”. In our example “Parcel” is the “Origin class” while
“Building” is the “Foreign class”.
When the association is connected you should give it a name and define multiplicity. To
define which columns that store the connection information you have to add two “Tagged
values”. The first is called “OriginPrimaryKey” and is given the value “OBJECTID”. The
second is called “OriginForeignKey” and is given the value “ParcelID”.
Here we have chosen “Parcel” as the origin class since one parcel can be connected to many
buildings. If we would have chosen “buildings” as the origin class we would have had to have
an undefined number of columns to store the links to different buildings in the “Parcel” table.
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Create the remaining object classes above and perform the consistency check from time to
time. When the model is finished you can move on to the next step and import it into ArcGIS.
Importing the XML file into ArcGIS
To import your XML model you start ArcCatalog under Start – Programs - ArcGIS –
ArcCatalog. ArcCatalog is the software used to manage databases and to connect to various
geographical data sources.
Before we can import our model we have to create a new “Personal geodatabase”. Right click
in your home directory to create a new one.
Next we have to find the tool that imports the XML – file. Chose Tools – Customize. A
window is shown called Customize. Click on Commands and chose Case Tools under
Categories. Under Commands you know have a tool called Schema Wizard (see fig. 1). Drag
and drop this command onto a toolbar. Close the customize window.
Fig. 1 The Schema Wizard can be found in the Customize window.
Next you click on the new symbol just added to the toolbar. After some time a window called
Schema Wizard is shown. In the firs window you press Next. In the Second window you chose
Model stored in XMI file and then browse to find the XMI – file created in Visio. Click Next.
In the next window you can see the object classes that will be created. Click Next and in the
last window you click Finish. Finally you can double-click on the personal Geodatabase to
see that your object classes have been created.
Add data to your database in ArcMap. Choose Tools – ArcMAP. After a while ArcMap has
started. In the first window you chose to start using ArcMap with a new empty map. To
connect to your database you choose Tools – Add data. Then you browse to find your
database and select all the object-classes in the database that you would like to edit in
ArcMap. The object classes will be shown in the legend window in ArcMap and now you can
start editing, adding new objects, etc. If you are not familiar with creating new objects in
ArcMap, use the Editor Menu and read about how to use it in Help under Contents – Editing
in ArcMap – Creating New Features.
Finally you should produce a nice map (with appropriate colours, etc. like in Exercise 1:
Introduction to ArcGIS of course Visualization Techniques) showing your database
implemented in ArcMap. Produce a pdf file of this map (see Exercise 1: Introduction to
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ArcGIS of course Visualization Techniques for how to do that) and submit it to the exercise
supervisor.
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