GST 101 Introduction to Geospatial Technology��Unit 2 – Understanding Spatial Data �Module 2.2 Location and Attribute Data ���� � �

Ann Johnson

Associate Director

ann@baremt.com

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Based upon work supported by the National Science Foundation under Grants DUE 1304591, DUE 164409, DUE 1700496, DUE 1937177, Due 1938717 DUE 1937237, 2030206 and 2015927. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Spatial and Attribute Data

• Historically, creating or finding appropriate data was a major project objection with 80% of the budget allocated to the task
• Once created, data became a tightly held, valuable asset

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• Today digital data may still need to be created, but there is an overwhelming amount of free or low-cost digital data available for use in projects!

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• Determining how these data sets were created and assessing quality and

fitness for use (scale, completeness, currency) in a project are extremely important!

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Think Metadata – Reviewed Carefully!

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• The saying from computer science should be emphasized

Garbage in, Garbage Out

Your project and results hinge on ethically using only “good and appropriate data” for your project!

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Some Sources For Data – Location and Attributes

Data Sources

• Primary
• Remote Sensing (Satellite, aerial, droned)
• Sensors and sensor webs (temperature, stream gauges, traffic, etc.)
• Global Position Systems (GPS) – locations
• Secondary
• Scanned maps/images
• Documents – text, tables, graphics for attributes
• Digitizing data from hardcopy maps

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Other Sources of Digital Data – both documents and digital online resources

• Government – local, state and federal
• Private Sector - free and for purchase
• Online Mapping – browser-based mapping and access to data
• Volunteer Geographic Information (VGI) – crowd sourcing

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Raster and Vector Data Collection

Primary raster data collection can use satellites and aerial vehicles (fixed wing, drones, etc.)

Primary vector data collection can use surveying tools and GPS (Global Positioning Systems), and Sensors

• For surveying, locations of objects is determined by angle and distance measurements from known locations.

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NASA - Landsat

Bolstad, Fig 3-13

Bureau of Land Management - Careers

Raster Secondary Data Capture

• Secondary data sources are digital and analog datasets that were originally captured in another format (such as paper or film)
• The data needs to be converted (by scanning or digitizing) the original format of data into digital data formats 
• This was an important source of data in the past, while still useful, it has become less important for many projects

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https://smoothsolutions.com/services/large-format-scanning/

Vector Secondary Data Capture

Collection of vector objects from hardcopy and digital maps and imagery

• Digitizing – Capturing features by tracing them:
• using a digitizing tablet, puck and hardcopy map (less common today)
• Heads up – using a digital image on computer monitor and a mouse
• Photogrammetry – the science and technology of making measurements from imagery

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Bolstad, Fig. 4-12

Bolstad, Fig. 4-11

https://www.satpalda.com/blogs/concepts-of-photogrammetry

USGS – Data and the National Map Products and Services

https://www.usgs.gov/core-science-systems/national-geospatial-program

USGS National Geospatial Program and Training https://www.usgs.gov/core-science-systems/national-geospatial-program/training

USGS – The National Map

https://viewer.nationalmap.gov/advanced-viewer/

National Map Viewer – Imagery and Elevation Data

US Interagency Coastal Data Inventory from NOAA

https://coast.noaa.gov/inventory/

Interactive Maps and Data – New Experimental Data Dashboards

https://dashboard.waterdata.usgs.gov/app/nwd/?region=lower48&aoi=default

Links To National Geospatial Data Assets (NGDA) Themes

Connecting Location of Features to Attributes

• Many datasets have features with limited amount of data about the features – details about attributes for the features such as what, who, when, . . .
• Tables of attributes about features may not include instructions on how to display the attributes to a geographic location
• One method is to link or join tables of attributes to locations using a common data field in both datasets
• For example, a table about individuals education levels for counties in a state may not include location information, but a census dataset may have both location information and an attribute field that can be used to link to the two data sets
• This topic will be covered in later Units of this course

US Census Bureau�

https://data.census.gov/cedsci/

US Data.gov �The Home of the U.S. Government’s Open Data

Weather and Climate - NOAA

http://nws.noaa.gov/gis/

Remote Sensed Imagery – Landsat, Sentinel 2

http://landsatlook.usgs.gov

Local and State Resources

Many local governments and States are sharing their data – either online or will provide access

• Search for data online or contact your local (town, city, county) and state government GIS departments
• Data can include imagery, property boundaries, roads (streets and street centerlines, waterways, elevation (LIDAR), and much more
• Scale for locally collected data may be higher resolution than state data
• Metadata:
• Be sure to check how and when it was collected and updated
• Note what map projection and coordinate system the data is in
• How it can be used and shared
• Keep your metadata about your data up to date!

Mapping Resources From Other Entities

Data From Universities

http://eos-earthdata.sr.unh.edu/

National Geographic Mapmaker

https://mapmaker.nationalgeographic.org/#/

ArcGIS Online by ESRI �http://www.arcgis.com

Google Earth�http://www.google.com/earth/

Remember Your Metadata

• Whatever the source of your data, document it!
• What
• When
• Who
• Why
• Methods of collection, update
• Coordinate System, Projection, Datum
• Data Dictionary – description of data sets, attributes and relationships
• Permissions and legal/ethical use
• How you accessed the data and how you may have modified it!
• Etc!

See GeoTech Center website (https://geotechcenter.org) �for additional Model Courses and other curriculum resources. ���������Note: some content is a derivative of other authors���

Ann Johnson

Associate Director

ann@baremt.com

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2-15-2021 V8