GIS Midterm 2 Review

• GIS is the focus of the Midterm 2 review.
• The Midterm 2 will be a 20-minute closed book paper test, followed by a short lecture on 'Spatial Analysis', during lecture time on Tuesday.

Five Components of GIS

• People: Researchers, technicians, and analysts use GIS to ask questions, choose data, collect, analyze, and interpret results.
• Hardware: Computer systems, technical equipment, and networks are used for GIS operations.
• Data: GIS uses spatial data (spatially located) like vector and raster data, image data, and attribute data (non-spatial).
• Software: GIS software provides functions to store, analyze, and display geographic information.
• Methods: Guidelines, procedures, and standards are used for analyzing and applying GIS.

Geospatial Data Models

• Geospatial data models include vector and raster data.
• Vector data consists of points, lines, and polygons.
• Raster data consists of cells/pixels.

Raster Data Model

• Rasters typically represent continuous surfaces but sometimes have discrete breaks.

Vector Data Model

• Vector data consists of points, lines, and polygons.

The Vector Data Model

• Objects in vector format (point, line, or polygon) that represent a geographic entity on a digital map are called "features".
• Features that represent the same type of geographic entity are grouped into a "feature class."
• Features are distinct and saved in feature classes.

Vector Model Attributes

• Point, lines, and polygons can have 'attributes' that provide non-spatial information about the geographic feature.
• Attributes are stored in a table, acting as a spreadsheet.
• Features are linked to their attributes in the table.
• Each feature is linked to a record (row) in the table, with a one-to-one correspondence between features and records.
• When a feature is selected, its corresponding record in the table is also selected.

Projects in ArcGIS Pro

• ArcGIS Pro projects are a collection of related items like maps, layouts, tables, charts, and data connections.
• The *.aprx file connects to the data but does not save the data itself.

ArcGIS Pro User Interface

• The ArcGIS Pro user interface is made up of a Ribbon, View and Panes

Creating a Project

• When creating a project, the project must be named and a save location needs to be selected.
• A default 'geodatabase' (*.gdb) is created with the same name as the project.

Map View

• Map View displays a collection of layers drawn in a particular order for a given map extent and map projection.

Features

• A feature is a representation of a real-world object on a map
• Features must have a geometry type and spatial/location information to be displayed on a map
• Features utilize vector data

Feature Class

• A feature class is data that thematically groups similar features recorded in a vector file
• All features in a feature class share the same geographic extent, coordinate system, and attributes
• Note: Feature class is not the same as a feature layer. Where the data is saved as a file, is not the same as deciding how to display it

Feature Layer

• Feature layer is created when a feature class (data) is added to the map
• Displayed as a feature layer
• This layer is linked to the data stored on the network
• The layer contains the common properties for displaying data on the map, original data is not changed (unless you're in editing mode)
• the 'in-memory' representation of the feature data

Lay out View Maps

• Layout view maps are a representation of geospatial data.
• Layout views is designed to convey information.

Geospatial Data Types

• Shapefile is a non-proprietary common sharing format
• Geodatabase files are ESRI-specific with more functionalities.

Shapefile

• An earlier ArcGIS data model is vector data only.
• The open data model is useful for sharing data.
• Similar basic functionality, but lacks some functionality such as geoprocessing, topology, network, and routing.

Geodatabase

• Geodatabases can store complex data types, such as rasters, vector datasets, relationships, topology, and networks.
• They are fully supported by ArcGIS and allows for multi-user access.
• Geodatabases are proprietary.