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Handouts

Today’s cookbook

Graded stuff

Class 21 (Tuesday 18 November 2014)

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  1. Cool Maps!
  2. The Challenge!
  3. What is Digitizing?
  4. Details!
  5. Assignment for Thursday

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Week

Date

Topics

Assignment

Week 1

9/4 (Th)

What is GIS?

HW1

Week 2

9/9, 9/11

Web GIS I

HW2

Week 3

9/16, 9/18

Web GIS II

HW3

Week 4

9/23, 9/25

GIS Mapping 1

HW4

Week 5

9/30, 10/2

GIS Mapping 2

HW5

Week 6

10/7, 10/9

GIS Mapping 3

HW6

Week 7

10/14, 10/16

Lying with Maps Project

Project 1

Week 8

10/21, 10/23

Review and Reflection I

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Week 9

10/28, 10/30

GIS Data I

HW7

Week 10

11/4, 11/6

GIS Data II

HW8

Week 11

11/13 (Th)

GIS Data III

HW9

Week 12

11/18, 11/20

GIS Analysis I

HW10

Week 13

11/25 (Tu)

GIS Analysis II

HW11

Week 14

12/2, 12/4

GIS Analysis III

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Week 15

12/9, 12/11

Review and Reflection II

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Course Schedule

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday

Data

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  • Streamed data from ArcGIS Online
  • Downloaded vector data
  • Downloaded raster data
  • Created data by address mapping
  • Created data by (X,Y) mapping
  • Created data with a GPS
  • Created data by digitizing

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday

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The Challenge!

We collected water samples along the Westfield River and recorded information in our field notebook. Our GPS ran out of batteries so we were not able to collect the geographic coordinates of our sampling locations. Luckily we took good field notes and we can identify the sampling locations on our base layer.

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In other words: We need to create the spatial data and then enter the attribute data - then we have geospatial data and we can make a make and perform analysis.

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The Challenge!

name

id

date

temp_F

pH

comment

image_video

Sample 1

20141112_wr1

11/12/2014

55

7

water here is turbid

enter URL

Sample 2

20141112_wr2

11/12/2014

60

4

Smell like rotten eggs?

enter URL

Sample 3

20141112_wr3

11/12/2014

45

8

Saw a trout

enter URL

In other words:

We need to first create the spatial data and then second enter the attribute data - then we have geospatial data and we can make a make and perform analysis.

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday

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Digitizing = Creating New Geospatial Data

On-Screen Digitizing

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  • Clicking around on a computer screen.
  • Making more digital data from already existing digital data.

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Digitizing Tablets

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  • Clicking around on a special table that you cover with a map.
  • Today we usually scan the map and do on-screen digitizing.

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In-Situ Digitizing

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  • ‘Clicking’ around outside with a GPS receiver.
  • Take notes and photographs.
  • Based on those add your attribute data later in ArcGIS.

Digitizing is not just clicking-around!

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  • Clicking around gives you the spatial data!
  • Typing attribute data gives you attribute data!

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Together you have geospatial data!

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Digitizing = Creating New Geospatial Data

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2003

2011

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Digitizing = Creating New Geospatial Data

The Basic Digitizing Process

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  1. Create a new = empty feature class or shapefile to serve as the ‘shell’ into which you digitize your new spatial features.

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  • Open this empty feature class or shapefile in ArcMap.

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  • Add the field(s) you need to the attribute table.

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  • Digitize your spatial features = the spatial data! (Step 3 and 4 can be reversed)

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  • Enter the attribute information = the attribute data!

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⇒ Now you have new, original geospatial data

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Clicking has no intelligence! The intelligence comes from adding and using attribute data!

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Digitizing = Creating New Geospatial Data

Good Example

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  • Streets digitized as polylines
  • Buildings digitized as polygons

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An attribute field was added and the building land use entered into attribute table :

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1 = commercial

2 = public

3 = residential

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This allows you to show the buildings as a choropleth map where the building color indicates its land use.

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Digitizing = Creating New Geospatial Data

​

Task

Challenge

Step 1

Create a new feature class or shapefile.

Define the correct coordinate system.

Step 2

Add what you created in Step 1 to map.

None!

Step 3

Digitize the spatial features.

Use the editing tools.

Step 4

Add the new fields to the attribute table.

Define the correct field types.

Step 5

Enter the attribute information.

Be consistent!

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday

http://www.screencast.com/t/vFEFz8Q3uX

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Create a new feature class or shapefile

Analogy

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Create a new and empty MS Word document = a blank page…now you can start typing!

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Here you do a similar thing: you create a new empty geospatial data set.

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Now you add it to your map, digitize the spatial data, and enter the attribute data.

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Do Section 3.1

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Create a new feature class or shapefile

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Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

The Spatial Reference/Coordinate System tells ArcGIS two things:

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  • Where on Earth to map a geospatial data set.
  • How to convert the 3D shape of the Earth into the 2D shape displayed on your computer screen.

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ArcGIS needs to know both things to accurately place and map a feature class or a shapefile onto your map.

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Whatever you do - you need to define the Coordinate System / Spatial Reference!

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Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

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Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

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Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

http://sandbox.azavea.com/projection-overlays/

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Vector Data�= Latitude and longitude of your spatial features.

Raster Data�= Latitude and longitude of each grid cell.

The Coordinate System / Spatial Reference is either embedded in the feature class or included as the *.prj file that is part of each shapefile family.

Coordinate System or Spatial Reference

Where and how to map the coordinates of spatial features on the 3D Earth.

How to project the 3D Earth as a flat 2D map on your screen.

Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

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Vector Data�= Latitude and longitude of your spatial features.

Raster Data�= Latitude and longitude of each grid cell.

Coordinate System or Spatial Reference

Where and how to map the coordinates of spatial features on the 3D Earth.

How to project the 3D Earth as a flat 2D map on your screen.

The Coordinate System / Spatial Reference is either embedded in the feature class or included as the *.prj file that is part of each shapefile family.

Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

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Vector Data�= Latitude and longitude of your spatial features.

Raster Data�= Latitude and longitude of each grid cell.

Coordinate System or Spatial Reference

Where and how to map the coordinates of spatial features on the 3D Earth.

How to project the 3D Earth as a flat 2D map on your screen.

The Coordinate System / Spatial Reference is either embedded in the feature class or included as the *.prj file that is part of each shapefile family.

Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

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Vector Data�= Latitude and longitude of your spatial features.

Raster Data�= Latitude and longitude of each grid cell.

The Coordinate System / Spatial Reference is either embedded in the feature class or included as the *.prj file that is part of each shapefile family.

Defining the Coordinate System/Spatial Reference for a new feature class or shapefile can be difficult.

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Simple Tricks:

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  1. Import from your baselayer (MassGIS, ArcGIS Online, etc.).
  2. Use WGS 84.

Coordinate System / Spatial Reference: Earth is 3D, the map is 2D.

Coordinate System or Spatial Reference

Where and how to map the coordinates of spatial features on the 3D Earth.

How to project the 3D Earth as a flat 2D map on your screen.

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Digitizing = Creating New Geospatial Data

​

Task

Challenge

Step 1

Create a new feature class or shapefile.

Define the correct coordinate system.

Step 2

Add what you created in Step 1 to map.

None!

Step 3

Digitize the spatial features.

Use the editing tools.

Step 4

Add the new fields to the attribute table.

Define the correct field types.

Step 5

Enter the attribute information.

Be consistent!

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The Challenge!

name

id

date

temp_F

pH

comment

image_video

Sample 1

20141112_wr1

11/12/2014

55

7

water here is turbid

enter URL

Sample 2

20141112_wr2

11/12/2014

60

4

Smell like rotten eggs?

enter URL

Sample 3

20141112_wr3

11/12/2014

45

8

Saw a trout

enter URL

In other words:

We need to first create the spatial data and then second enter the attribute data - then we have geospatial data and we can make a make and perform analysis.

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Class 21 (Tuesday 18 November 2014)

​

  • Cool Maps!
  • The Challenge!
  • What is Digitizing?
  • Details!
  • Assignment for Thursday
  1. Watch tutorial videos
  2. Digitize planes at Westover.
  3. Send me the map as a JPG image.