ESRM 250/CFR 520 Autumn 2009 Phil Hurvitz Tables ESRM 250/CFR 520 Autumn 2009 Phil Hurvitz 1 of 42

Using ArcMap tables Querying tables Table relationships Overview Using ArcMap tables Querying tables Table relationships Graphs from tables 2 of 42

Using ArcMap tables: Introduction Tables are just as important as coordinate (map) data Tables are used to hold attribute data Tables can be used to hold data that are not explicitly spatial in nature Tables are the source of all basic statistics 3 of 42

Using ArcMap tables: Overview Creating tables from existing sources Creating a new table Adding fields (columns) to tables Adding records (rows) to tables Editing values in table records Calculating fields 4 of 42

Creating tables from existing sources Tables can be created from existing sources: dBase files ASCII files (tab or comma delimited) INFO files ODBC connections 5 of 42

Creating tables from ODBC connections Tabular data can be obtained from ODBC databases (e.g., Oracle, Access) 6 of 42

New (dBase, GDB) tables can be created from scratch Creating a new table New (dBase, GDB) tables can be created from scratch Creates a new file on disk New table is empty 7 of 42

Adding fields to tables Each field must be defined at add time Data type and storage parameters need to be defined 8 of 42

Tips for defining fields Field data types should match the data they will store Short Integer: Whole numbers from -32,768 to 32,768 Long Integer: Whole numbers from -2,140,000,000 2,140,000,000 Float: single-precision floating-point numbers with an accuracy to 6 places past the decimal Double: double-precision floating-point numbers with an accuracy to 15 places past the decimal Date: January 1, 0100 to December 31, 9999 Text: 1 - 255 characters 9 of 42

Tips for defining fields Precision = number of digits Scale = digits to the right of the decimal point e.g., 100.27 precision = 5 scale = 2 10 of 42

Adding records to tables Records can be added ad hoc to stand-alone tables Do not add records to feature data (point, line, polygon) tables Adding features (feature editing) will automatically add a record to the feature attribute table Adding records to feature attribute tables will result in “phantom” records that are not associated with shape features 11 of 42

Adding records to tables Records can be added ad hoc to stand-alone tables New records will have null values for all fields until updates are made new record 12 of 42

Values in a new field can be generated based on calculated expressions Calculating fields Values in a new field can be generated based on calculated expressions Expressions can use other fields Acts on selected set of records 13 of 42

Using ArcMap tables Querying tables Table relationships Overview Using ArcMap tables Querying tables Table relationships Graphs from tables 14 of 42

Displaying selected sets Modifying selected sets Querying tables Making queries Sorting records Displaying selected sets Modifying selected sets Basic descriptive statistics Table summaries 15 of 42

Select records from tables Making queries Select records from tables “Select by attributes” Graphical interface to table data Selected records in cyan 16 of 42

Displaying selections Displaying selected records will show only those records that are in the selected set 17 of 42

Record can be sorted ascending or descending by field Sorting records Record can be sorted ascending or descending by field 18 of 42

Displaying selected sets Selecting records from feature tables also selects features from layers (and vice versa) 19 of 42

Modifying selected sets Existing selections can be broadened or narrowed Additional query criteria Add to selection Remove from selection Further narrow down current selection 20 of 42

Basic descriptive statistics Basic descriptive statistics can be generated for a field will describe selected set (or all records if there is no active selection) 21 of 42

Summarizing tables Creates a new table Table summaries Summarizing tables Creates a new table Summarizes values in numeric fields by values in a categorical field One output record per unique value in the (categorical) field of interest Different summary statistics available 22 of 42

Table summaries 23 of 42

Using ArcMap tables Querying tables Table relationships Overview Using ArcMap tables Querying tables Table relationships Graphs from tables 24 of 42

Record relationships among tables One-to-one relationship every record in Table A has a matching value in Table B Table B Table A 25 of 42

Record relationships among tables Many-to-one relationship Many records in Table A have a match with only 1 record in Table B Table A Table B 26 of 42

Record relationships among tables One-to-many relationship Only 1 record in Table B has a match with many records in Table B Table A Table B 27 of 42

Creates a virtual join (does not alter data sources) Joining tables Creates a virtual join (does not alter data sources) Used for: one-to-one many-to-one 28 of 42

Does not join, but allows simultaneous selections Relating tables Does not join, but allows simultaneous selections Used for: one-to-one many-to-one one-to-many 29 of 42

Relating tables “Relate” updates the selection on the related table based on field relationships 30 of 42

Using ArcMap tables Querying tables Table relationships Overview Using ArcMap tables Querying tables Table relationships Graphs from tables 31 of 42

Making graphs from tables What are graphs? Creating graphs from tables Graph elements Graph types Graph legends Axis properties Axis increments and grid lines Displaying multiple fields 32 of 42

Graphical representation of tabular data What are graphs? Graphical representation of tabular data numbers can be difficult to interpret graphs are easier to interpret 33 of 42

Graphs are dynamically linked to tables What are graphs? Graphs are dynamically linked to tables A selection on the table will be reflected in the graph 34 of 42

Creating graphs from tables 35 of 42

Creating graphs from tables 36 of 42

Graphs have many elements to format Graph elements Graphs have many elements to format 37 of 42

A number of different types and subtypes of graphs exist Graph types A number of different types and subtypes of graphs exist 38 of 42

X and Y axes have various properties Axis properties X and Y axes have various properties 39 of 42

Axis increments and grid lines Increments and grid lines can be formatted in different ways 40 of 42

Axis increments and grid lines A maximum value can be specified Be careful, the graph no longer shows the data range 41 of 42

Displaying multiple fields Multiple fields can be displayed in the graph Comparison of variables 42 of 42