GIS Lecture 4: Data GIS 1
Outline Data Types, Tables, and Formats Geodatabase Tabular Joins Spatial Joins Field Calculator ArcCatalog Functions GIS 2
Data Types, Tables, Formats GIS 3
Directly Loadable Data Types dbase (.dbf) - field name maximum length of 10 characters Text with comma- or tab-separated values (.csv) Microsoft Access (.mdb) Excel (.xls) GIS 4
Proper Data Table Formats First row must be the field names -(e.g., Pop5To17, Area, and Capacity) Field naming convention -first character is a letter -remaining characters be any letters, digits, or the underscore character (no spaces) All additional rows of a data table contain attribute values GIS 5
Data Types GIS 6
ESRI Data Types Shapefile - older format - actually made up of 4 files (shp, shx, dbf, prj) Geodatabase - newer format - relational database - similar to Access database -.gdb file extension GIS 7
Geodatabases Geodatabase with multiple data types GIS 8
Geodatabases Manages features, tables, images inside a database management system (DBMS) Enterprise (ArcSDE) geodatabase -Multiple editors at a time -Requires a host DBMS -SQL Server, Oracle, or IBM DB2 Personal/File geodatabase -Single editor at a time GIS 9
Creating New Data GIS 10
Import Data Into Geodatabase Shapefiles, data tables, rasters GIS 11
Export Data From Geodatabase GIS 12
Tabular Joins GIS 13
Tabular Joins Putting two tables together to make one table Join with common field attributes Common fields do not need to have the same field names Must have the matching values and data type (e.g., text vs. numeric) GIS 14
Tabular Join Example County Property Assessment Assesses the value of each land parcel and its structures and sets a property tax rate (= assessed value * tax rate) GIS 15
Property Data w/ no geography Parcel ID, Map Lot Block Number, Address, Value, Sale Date and Price, etc. GIS 16
GIS Parcels Layer GIS 17
Add Data Table in ArcMap GIS 18
Add Parcels Shapefile GIS 19
Choose Fields to Join GIS 20
Join Data GIS 21
Join Result Property fields are added to the Parcels attribute table GIS 22
Map with Property Data GIS 23
Problems with Joins Data in fields not exactly the same Must remove dashes! GIS 24
Problems with Joins Different data field types text numeric GIS 25
Spatial Joins GIS 26
Spatial join example You have census block group centroid points with housing fuel data You want to know housing fuel data by neighborhoods But there are no attributes in common Spatial join needed GIS 27
Spatial joins Points to polygons Spatially joins points (block centroids) within polygons (neighborhoods) Joins using shape (not attribute field) GIS 28
Spatial joins Right click polygon layer (neighborhoods) GIS 29
Join result New polygon feature GIS 30
Join result Count how many points are in each neighborhood Sums adds up the field values within each neighborhood GIS 31
Count result Number of points in each polygon GIS 32
Sum result One neighborhood example Central business district -4 block groups -Housing units with electricity fuel from block group centroids field [H040004] (80 + 299 + 128 + 292 ) -Sum = 799 GIS 33
Choropleth map result (sum) GIS 34
Field Calculator GIS 35
Field Calculator Functions Populate field with county name GIS 36
Field Calculator Functions Concatenate house number and street fields GIS 37
Field Calculator Functions Calculate Geometry GIS 38
ArcCatalog Functions GIS 39
ArcCatalog basic functions Copy, paste, rename, etc. View and edit properties View and edit metadata Create new files GIS 40
View and edit properties Projections, fields, etc. GIS 41
View & edit metadata GIS 42
Create new files Geodatabases, tables, features, etc. GIS 43
Summary Data Types, Tables, and Formats Geodatabase Tabular Joins Spatial Joins Field Calculator ArcCatalog Functions GIS 44
* Tutorial 4 tips * when it asks you if you want to Create an Index, YES this will help ArcGIS process your data faster the Calculation takes a long time to start; it looks like nothing is happening. Be patient! GIS 45
Tutorial 4-6 - flowchart Beat polygons Business points Business points with Beat ID field Business points with business type Business points only selection A B A A A B B A 1901 A 5812 A 5813 B 6654 B 1126 A 5812 A 5813 C D C C D C 3314 C 5813 D 2950 C 5813 Spatial Join Business points to Beat polygons Tabular Join Business points to SIC business type codes Query Business points with EatingDrinkingPlaces SIC business type codes ( 5812 or 5813 ) table of Business point counts Beat polygons with Business point counts Map coloring Beat polygons by their Business point counts 2 0 A 2 B 0 1 0 C 1 D 0 Summarize Tabular Join Symbolize count of Business points with EatingDrinkingPlaces in each Beat polygon table of Business point counts to Beat polygons color Beat polygons by count of businesses GIS 46