Announcements

• Flooding event this weekend.
• 2022 GEO 509 used lidar point clouds to analyze flood impact in this report.
• GEO 509 Workshop in Geospatial Technologies is offered this fall.
• Awards offered this spring.

Lidar scanner?

• Have a scanner on your phone?
• Use the 3D scanner App to scan objects with GPS enabled.
• Export as an .xyz file.

Change

• Spring heralds change in the Bluegrass.
• Extreme weather events are becoming more common.
• How do we measure change?

Mapping change

• Satellites show damage from 2021 tornadoes. (NASA Worldview)
• Change in NDVI (plant health).
• Site surveys.

Errors!

• The dreaded 999999 ArcGIS Pro error.
• Diabolically unknown.
• How to diagnose and fix is a challenge.
• It is worth the effort to find a fix if only to understand your tools better.

Many python functions

• can be run via a GUI tool.
• Extract by Mask is one.
• Search Analysis > Tools for the tool name.

GUI Tools

• Why not just use the GUI?
• We can but it's a lot of clicking
• and we can't save/code our workflow.

Pauer Cartography Award

• Submissions are open!
• Cash prize
• Traditional cartography, 3D mapping, and web maps
• Let me know if you want to submit.

Some sites from mod 5

First goal

• How much of x is in (or near) y?
• Highly accurate and precise data now.
• Essential GIS.
• Module 2: How many populated places near Kentucky's highest park?

Second goal

• Where x_n is in y, z exists.
• x_n is any number of variables.
• z is not directly observed, but predicted.
• Spatial modeling.
• Module 3: Where to have a picnic and where are tall trees?

Third goal

• Test our prediction in the field.
• Visualize and measure complicated data.
• Make a useable artifact.
• Module 4 & 5: Field mapping and Intro to lidar.

Current goal

• Where x_t1 != x_t2, e occurred.
• x_t is same variable at different times.
• != is not equal to – they are different.
• e is an event that caused the difference.

Witness

• Global climate change from satellites.
• Local from differences in elevation.
• From your daily adventures.

There is nothing permanent except change.

– Heraclitus, 500 BCE

We will be known forever by the tracks we leave.

– Dakota Tribe

Land use change

• NLCD captured every couple of years (2001-2023)
• Raster cells are 30m x 30m and align across years.
• Class codes (land cover types) are the same across years.
• c_t1 != c_t2 if true, change occurred.

In-class task

• Open the explore-change-landcover.ipynb Notebook.
• Find how much land was developed between 2001 and 2019
• within 20 miles of your hometown.

Mass terrain modification

• Dam building. Mountain Top Removal (MTR).
• Surface mining creates overburden
• which becomes valley fill.
• Explore Google Maps

Elevation change

• Lidar derived DEMs from 2010 to current.(2-5ft resolution)
• USGS DEMs from the early 1990s. (10m resolution)
• change = DEM_t2 - DEM_t1
• If it is not close to 0, change occurred.

In-class task

• Open the explore-change-elevation.ipynb Notebook.
• Find a site with wide-scale elevation modification
• and show the change between the DEMs
• within two miles of the center of the site.

Above-ground change

• Buildings and trees lost and gained.
• A record of neighborhood change.
• New technique available with lidar point clouds.

Technique

• Compare lidar Phase 1 to Phase 2
• via their DSMs.
• change = DSM_phase2 - DSM_phase1
• You'll need two point clouds to do this.

In-class task

• Create two DSMs for the same area,
• Phase 1 and Phase 2.
• Open the explore-change-surface.ipynb Notebook.
• Subtract Phase 1 from Phase 2.
• Symbolize the output raster with a diverging color ramp.

3D Visualization

• Colorize Phase 1 point cloud by amount of removal
• and Phase 2 by amount of addition.
• Show both simultaneously.
• 🤯

Colorize

• Point cloud can be colored by any RGB image.
• Export raster and force rendering to RGB.

Sunrise spring equinox

• Create hillshade from DSM
• enabling shadows.

Colorize

• Color point cloud with the custom symbolized hillshade.
• Use a Notebook or the Analysis > Colorize LAS tool.

In-class task

• Color Phase 1 point cloud by amount of removal
• and Phase 2 by amount of addition.
• Make a layout showing change.

STOP