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Next GIS eSeminar: Next GIS eSeminar: Wed. Nov 8th Wed. Nov 8th ““Agent models of population “ Agent models of population “

Dick Ettema (Utrecht)Dick Ettema (Utrecht) Two more lectures: Two more lectures:

1.1. Geographic AnalysisGeographic Analysis

2.2. GIS and Society, Participatory GISGIS and Society, Participatory GIS GIS Day: November 15GIS Day: November 15 Final Exam: Friday, December 1Final Exam: Friday, December 1

Associating TablesAssociating Tables

Because features often have many attributes, most Because features often have many attributes, most database design guidelines promote organizing database design guidelines promote organizing your database into multiple tables—each focused your database into multiple tables—each focused on a specific topic—instead of one large table on a specific topic—instead of one large table containing all the necessary fields. This scheme is containing all the necessary fields. This scheme is more efficient because it eliminates duplicate more efficient because it eliminates duplicate information in the database–you store the information in the database–you store the information only once in one table. Tables can be information only once in one table. Tables can be "connected" so that when you need information that "connected" so that when you need information that isn't in the current table, you can access it from a isn't in the current table, you can access it from a table associated with it. table associated with it.

Two tables can be connected if there is a Two tables can be connected if there is a similar field in each table containing similar field in each table containing common values. Each table must have at common values. Each table must have at least one field containing unique values for least one field containing unique values for each record; in database terminology, this each record; in database terminology, this field is called the primary key. Even if field is called the primary key. Even if there are duplicate values in all the other there are duplicate values in all the other fields, the primary key ensures that each fields, the primary key ensures that each row will be unique. row will be unique.

Row uniqueness is important when connecting two Row uniqueness is important when connecting two tables because you want to make sure the correct tables because you want to make sure the correct rows are matched together. As a general rule, you rows are matched together. As a general rule, you connect tables from a primary key field in one table connect tables from a primary key field in one table to the common field (called the foreign key) in the to the common field (called the foreign key) in the other table. In the next graphic, the ZONE_CODE other table. In the next graphic, the ZONE_CODE field exists in both tables, contains common values field exists in both tables, contains common values in each, and has unique values in each row in the in each, and has unique values in each row in the attribute table on the right. The tables can be attribute table on the right. The tables can be connected based on this field. connected based on this field.

In each table above, ZONE_CODE contains the same values—codes for zoning types. The attribute table on the right also contains the descriptions for each code; this information is not stored in the feature attribute

table, but it is information that users will want to access often. The tables will be connected so that the

zoning descriptions can be easily accessed.

Table RelationshipsTable Relationships

In ArcMap, you can connect two tables using In ArcMap, you can connect two tables using either a join or a relate. In order to know either a join or a relate. In order to know which method to use, you need to know how which method to use, you need to know how individual records in each table relate to one individual records in each table relate to one another. You need to know if one or more another. You need to know if one or more than one record in the first table is associated than one record in the first table is associated with one or more than one record in the with one or more than one record in the second table. There are four possible second table. There are four possible relationship types (also called relationship types (also called cardinalitycardinality): ): one-to-one, one-to-many, many-to-one, and one-to-one, one-to-many, many-to-one, and many-to-many. many-to-many.

CardinalityCardinality

A property of a relationship between objects in a A property of a relationship between objects in a database, describing how many objects of type A database, describing how many objects of type A are associated with how many objects of type B. are associated with how many objects of type B. Relationships can have one-to-one, one-to-many, Relationships can have one-to-one, one-to-many, many-to-one, and many-to-many cardinalities.many-to-one, and many-to-many cardinalities.

For example, one parcel can have one owner For example, one parcel can have one owner (one-to-one), one parcel can have many owners (one-to-one), one parcel can have many owners (one-to-many), many parcels can have one (one-to-many), many parcels can have one owner (many-to-one), or many parcels can have owner (many-to-one), or many parcels can have many different owners (many-to-many).many different owners (many-to-many).

Connecting tables with joinsConnecting tables with joins

You can connect two tables together in ArcMap You can connect two tables together in ArcMap using a join. Join works with shapefiles, using a join. Join works with shapefiles, coverages, and geodatabase feature classes. coverages, and geodatabase feature classes. Once the tables are connected, you can query, Once the tables are connected, you can query, symbolize, and analyze your data based on the symbolize, and analyze your data based on the joined values. joined values.

Table joins are designed for one-to-one or many-Table joins are designed for one-to-one or many-to-one relationships. For other cardinalities you to-one relationships. For other cardinalities you should use a relate instead of a join. If you join should use a relate instead of a join. If you join two tables that have one-to-many or many-to-two tables that have one-to-many or many-to-many cardinality, you will omit all records after the many cardinality, you will omit all records after the first match for each primary key value.first match for each primary key value.

When joining two tables, the names of the common When joining two tables, the names of the common fields need not be identical but the fields must be the fields need not be identical but the fields must be the same type (e.g., text, date, float, etc.). The ArcMap Join same type (e.g., text, date, float, etc.). The ArcMap Join Data dialog is where you specify which tables you want Data dialog is where you specify which tables you want to join and which fields contain the values that will match. to join and which fields contain the values that will match.

Joined tables are not permanently connected. The fields Joined tables are not permanently connected. The fields from one table are appended to the other table. You can from one table are appended to the other table. You can tell from which table a field originates because its source tell from which table a field originates because its source table name displays in its field name. You can remove a table name displays in its field name. You can remove a table join whenever you want. Table joins are “virtual”; table join whenever you want. Table joins are “virtual”; that is, the two tables still exist as separate entities. that is, the two tables still exist as separate entities.

Connecting tables with relates Connecting tables with relates

Another way that you can connect tables in Another way that you can connect tables in ArcMap is by creating a relate. Like joining tables, ArcMap is by creating a relate. Like joining tables, relating tables defines a relationship between two relating tables defines a relationship between two tables and is also based upon a common field. tables and is also based upon a common field. Unlike joining tables, a relate doesn't append the Unlike joining tables, a relate doesn't append the fields of one table to the other. Instead, you fields of one table to the other. Instead, you access data in the related table by selecting access data in the related table by selecting records in one table and accessing the related records in one table and accessing the related records in the other table. records in the other table.

You relate tables instead of joining them when You relate tables instead of joining them when there is a one-to-many or many-to-many there is a one-to-many or many-to-many relationship between the tables. relationship between the tables.

The Attributes of parcels table and the Owners table have a one-to-many relationship (a parcel may have more than one owner). The two tables are related

based on the Parcel_no field. Selecting vacant parcels in the attribute table selects the records with

matching parcel numbers in the related table.

In ArcMap, you create a relate in the Relate dialog In ArcMap, you create a relate in the Relate dialog by choosing the tables you want to relate and the by choosing the tables you want to relate and the fields in each that the relate will be based on. To fields in each that the relate will be based on. To access data in a related table, open one of the access data in a related table, open one of the tables and select the records for which you want to tables and select the records for which you want to display related records. Click Options, point to display related records. Click Options, point to Related Tables, and click the name of the relate Related Tables, and click the name of the relate you want to access. The related table will display you want to access. The related table will display with the related records selected. It doesn’t matter with the related records selected. It doesn’t matter which table you open, because in ArcMap table which table you open, because in ArcMap table relates are bi-directional. relates are bi-directional.

If your data is involved in both joins and If your data is involved in both joins and relates, the order in which the joins and relates, the order in which the joins and relates are created relates are created is significantis significant. If you have . If you have a table for which you have created a relate a table for which you have created a relate and you join another table to it, the relate will and you join another table to it, the relate will be removed. If you perform a relate on a be removed. If you perform a relate on a joined table, the relate is removed when the joined table, the relate is removed when the join is removed. As a general rule of thumb, it join is removed. As a general rule of thumb, it is best to create your joins, then add your is best to create your joins, then add your relates.relates.

JoinJoin Suppose you have a parcels feature attribute Suppose you have a parcels feature attribute

table and another attribute table that contains table and another attribute table that contains the names of parcel owners. The graphic the names of parcel owners. The graphic below shows a one-to-one relationship. Each below shows a one-to-one relationship. Each parcel has only one owner, so each record in parcel has only one owner, so each record in the feature attribute table will relate to one the feature attribute table will relate to one record in the owners attribute table. For this record in the owners attribute table. For this type of relationship, you would use a table type of relationship, you would use a table join. join.

The graphics below show both a one-to-many and a The graphics below show both a one-to-many and a many-to-one relationship. On the left, one parcel can many-to-one relationship. On the left, one parcel can have many owners; therefore, the relationship is one-to-have many owners; therefore, the relationship is one-to-many. On the right, many parcels can have one owner, many. On the right, many parcels can have one owner, resulting in a many-to-one relationship. For a one-to-resulting in a many-to-one relationship. For a one-to-many relationship, you should create a table relate; for a many relationship, you should create a table relate; for a

many-to-one relationship, you should create a table join.many-to-one relationship, you should create a table join.

You can also have relationships where You can also have relationships where many features relate to many records in many features relate to many records in the other attribute table. In this situation, the other attribute table. In this situation, many parcels could have many owners. many parcels could have many owners. This is the most complex relationship and This is the most complex relationship and can be difficult to manage. For this type of can be difficult to manage. For this type of relationship, you should associate the two relationship, you should associate the two tables using a table relate. tables using a table relate.

Other items to discussOther items to discuss

sort, calculate, and freeze data in a table sort, calculate, and freeze data in a table create summary statistics create summary statistics edit feature attributes using the Attributes edit feature attributes using the Attributes

dialog dialog use the Field Calculator to update attribute use the Field Calculator to update attribute

values values create a graph create a graph create a report create a report

There are a number of ways you can There are a number of ways you can display attribute data. You can change the display attribute data. You can change the way data is displayed in a table, and you way data is displayed in a table, and you can take data out of the table and display can take data out of the table and display it as statistics or in a graph or report. it as statistics or in a graph or report.

Access and edit attribute data in Access and edit attribute data in ArcMap. ArcMap.

When you want to edit feature attributes, you start When you want to edit feature attributes, you start an editing session. When you're in an editing an editing session. When you're in an editing session, you can view the attributes of selected session, you can view the attributes of selected features by clicking the Attributes button to bring features by clicking the Attributes button to bring up the Attributes dialog. The Attributes dialog has up the Attributes dialog. The Attributes dialog has two parts: a tree view on the left that lists each two parts: a tree view on the left that lists each selected feature, and a pane on the right that selected feature, and a pane on the right that shows the attribute values for the feature currently shows the attribute values for the feature currently selected in the tree view. selected in the tree view.

If you select features from more than one If you select features from more than one layer, each layer that contains selected layer, each layer that contains selected features will be listed in the tree view. You features will be listed in the tree view. You can access individual selected features by can access individual selected features by expanding their layer expanding their layer

If you select features If you select features from more than one from more than one layer, each layer that layer, each layer that contains selected contains selected features will be listed features will be listed in the tree view. You in the tree view. You can access individual can access individual selected features by selected features by expanding their layer expanding their layer

You can edit the You can edit the attribute values for a attribute values for a single feature by single feature by clicking next to the clicking next to the field name and typing field name and typing in the new value. in the new value.

If you want to change If you want to change values for all the selected values for all the selected features at once, you can features at once, you can click the layer name and click the layer name and type the new value next to type the new value next to the field you want to the field you want to update. In the graphic update. In the graphic below, the OWNER below, the OWNER values for all the selected values for all the selected homes are being changed homes are being changed to "Alvi Contracting." to "Alvi Contracting."

Table manipulationTable manipulation

You can manipulate tables You can manipulate tables to change how data is to change how data is viewed. Right-clicking any viewed. Right-clicking any field brings up a context field brings up a context menu with many choices. menu with many choices. You can sort the record You can sort the record values in a selected field values in a selected field either in ascending or either in ascending or descending order. You can descending order. You can sort both numeric and sort both numeric and character fields. character fields.

You can calculate the You can calculate the values of selected values of selected records using the records using the Field Calculator. In Field Calculator. In the Field Calculator, the Field Calculator, you can update all the you can update all the values or a selected values or a selected set of values in a field set of values in a field at one time. at one time.

Using the Field Calculator Using the Field Calculator In ArcMap, you can edit feature attributes by In ArcMap, you can edit feature attributes by

creating simple calculations or logical creating simple calculations or logical expressions in the Field Calculator. The Field expressions in the Field Calculator. The Field Calculator works on selected features or on all Calculator works on selected features or on all features in a layer if there are none selected. features in a layer if there are none selected.

To access the Field Calculator, first start an To access the Field Calculator, first start an editing session, then open the desired layer's editing session, then open the desired layer's attribute table by right-clicking the layer name in attribute table by right-clicking the layer name in the Table of Contents. Choose Open Attribute the Table of Contents. Choose Open Attribute Table and when the table displays, right-click the Table and when the table displays, right-click the field you want to update. Choose Calculate field you want to update. Choose Calculate Values to display the Field Calculator. Values to display the Field Calculator.

To create an expression To create an expression in the Field Calculator, in the Field Calculator, you combine fields, you combine fields, functions, and operators. functions, and operators. As you click on fields and As you click on fields and functions, they appear in functions, they appear in the expression box. You the expression box. You can also type directly into can also type directly into the box. The expression the box. The expression below will update the below will update the VALUE field with the VALUE field with the results of multiplying each results of multiplying each feature's area by 1.5. feature's area by 1.5.

Freeze or unfreeze a columnFreeze or unfreeze a column Freezing a column locks a Freezing a column locks a

column as the left-most column as the left-most column in the table view. You column in the table view. You can then use the horizontal can then use the horizontal scroll bar to see the other scroll bar to see the other columns in the table. When columns in the table. When you scroll, the frozen column you scroll, the frozen column remains in place while all other remains in place while all other columns move. A frozen columns move. A frozen column is easily identified column is easily identified because it has a thick black because it has a thick black line separating it from the other line separating it from the other columns in the table. columns in the table.

Calculating statistics Calculating statistics After selecting features on the After selecting features on the

map or selecting records in a map or selecting records in a table, you may want to table, you may want to calculate simple summary calculate simple summary statistics for the data. (Choose statistics for the data. (Choose the Statistics option from the Statistics option from ArcMap's Selection menu)ArcMap's Selection menu)

After you select the layer and After you select the layer and field in the feature attribute field in the feature attribute table for which you want table for which you want statistics calculated, a list of statistics calculated, a list of summary statistics, as well as summary statistics, as well as a frequency distribution chart, a frequency distribution chart, display in the Selection display in the Selection Statistics window.Statistics window.

Graphs in ArcGISGraphs in ArcGIS Values for ArcGIS graphs Values for ArcGIS graphs

come directly from feature come directly from feature attribute tables. You can attribute tables. You can represent your data and represent your data and analysis results using analysis results using many styles of graphs, many styles of graphs, including both two- and including both two- and three-dimensional graphs. three-dimensional graphs. Some graphs are better Some graphs are better than others at presenting than others at presenting certain kinds of certain kinds of information. You should information. You should carefully consider the carefully consider the information you want to information you want to present before choosing a present before choosing a graph style. graph style.

Once you've created a graph, you can add Once you've created a graph, you can add it to a map in ArcMap's Layout View. it to a map in ArcMap's Layout View. When placed on the layout, a graph When placed on the layout, a graph becomes a graphic element that you can becomes a graphic element that you can size and position as desired. Once you've size and position as desired. Once you've placed a graph on a layout, however, it placed a graph on a layout, however, it becomes static and changes to the becomes static and changes to the graph's source table will not be reflected in graph's source table will not be reflected in the graph.the graph.

ReportsReports

A report presents tabular information about map A report presents tabular information about map features (from a feature attribute table) formatted in features (from a feature attribute table) formatted in an attractive manner. You can choose which fields an attractive manner. You can choose which fields from your table you want to display and how you from your table you want to display and how you want to display them. Once you've created a report, want to display them. Once you've created a report, you can place it on your map layout with your you can place it on your map layout with your geographic data or save it as a file for distribution. geographic data or save it as a file for distribution.

A report includes a title, page numbers and the A report includes a title, page numbers and the current date, summary statistics, images, borders, current date, summary statistics, images, borders, and, of course, the data from the feature attribute and, of course, the data from the feature attribute table. table.

Displaying your data in a report allows you to organize Displaying your data in a report allows you to organize your data. You can sort records based on the values in your data. You can sort records based on the values in one or more fields—given a list of cities, you could sort one or more fields—given a list of cities, you could sort them by total population, for example. You can also them by total population, for example. You can also group records and calculate summary statistics. For group records and calculate summary statistics. For example, you could group cities by their country. It would example, you could group cities by their country. It would then be easy to see which city has the largest population then be easy to see which city has the largest population in a given country. You can also calculate summary in a given country. You can also calculate summary statistics—sum, average, count, standard deviation, statistics—sum, average, count, standard deviation, minimum, and maximum values. minimum, and maximum values.

You can export reports to different file types, including You can export reports to different file types, including Adobe's Portable Document Format (PDF), Rich Text Adobe's Portable Document Format (PDF), Rich Text Format (RTF), or plain text (TXT).Format (RTF), or plain text (TXT).

Groups for Oslo ProjectGroups for Oslo Project Group 1:Group 1: Group 5:Group 5: Karianne FjellskaalnesKarianne Fjellskaalnes Ragnhild Andersen Merete OlsenMerete Olsen Kaja Killingstad

Group 2:Group 2: Group 6:Group 6:• Kathrine Akre Eric Strickler• Stian Berge Simon Tedder• Camilla Nestegard Luca Ippoliti

Group 3:Group 3: Group 7Group 7 Jens HalvorsenJens Halvorsen Sofie SkåraSofie Skåra Jostein TysildJostein Tysild Ida Skivenes Ida Skivenes Anne Grete TrevorAnne Grete Trevor Marie Therese Torstensson Marie Therese Torstensson

Group 4:Group 4: Group 8Group 8• Marie Hesselberg Simonsen Astrid Bjørlo• Liv Inger Gabrielsen Aslak Stensrud • Rikke Marie Fjell Jørgensen• Ida Sellereite Fjell