I had a access to a smartboard, so I had all of the students gather around (away from their computers) to go over the concepts from Day 2 in a group format. I asked them answer questions about menus and specific purposes of certain functions.
Vector Selection and Analysis – Hydro
Have the students load a far more complicated dataset for analysis. I used the Montana state extract for the USGS NHD (National Hydrography Dataset). Use this opportunity to talk about data scale compared to NaturalEarthData that they have been using.
add NHD Flowline, HUC8
Have the students select and create a memory layer for a specific HUC8 boundary
Clip the statewide flowline dataset to the HUC8 memory layer GDAL>Vector Geoprocessing>Clip vector by mask layer, save as memory layer
Have the students use ‘select by expression’ to isolate a specific river, for example: “GNIS_Name” = ‘Bitterroot River’
Copy the selected features>Paste them as a new memory layer
Calculate the statistics on the new River layer (Vector>Analysis Tools>Calculate Basic Statistics..) and ask the students which statistic tells us the length of the River (sum).
Vector Selection and Analysis – Summits
Have the students load a point dataset of mountain summits with an attribute value for elevation.
Open the attribute column and show how you can sort a column by clicking on the column header.
Ask the students to make a new memory layer of the 10 highest summits. See if they can do it and then talk about the different ways to accomplish this.
Use this opportunity to load the matching DEM of the area and use the identify tool to show that the value (meters) of the summits point dataset matches the pixel value of the DEM. Remind them of the difference between raster and vector data.
Vector Selection and Analysis – Fire Perimeters
Load a Fire Perimeter dataset. Talk about dataset scale and how this dataset contains overlapping polygons representing every day of a fire. (go into layer styling and reduce the opacity to show the overlaps). Talk about temporal data.
Ask the students how to isolate the LAST polygon, representing the final extent of a fire. (attribute table)
Have the students select by that attribute, paste as a new memory layer
Have the students calculate the statistics on the memory layer and ask them which statistic will tell us the total area burned in a given year.
Data Editing – Review
Review the data editing fundamentals that were learned on Day 2.
Have the students create a new .shp layer (not a memory layer). Talk about the difference between disk layers and memory layers. Have them create the new shapefile in an organized /data folder. Have them add a ‘Name’ attribute and talk about attribute field types (string, integer, double)
Load in a WMS imagery layer
Have the students digitize some building footprints in their town.
Save the edits, look at the timestamps on the file on the disk as they do this.
Save the qgis project and reinforce the difference between the qgis project file and the linked data within a qgis project file.
Student Project Work
Now I had the students start to work on their individual projects which they identified on day 2.
This involved lots of one-on-one time working through issues for each project and ran the gamut of all sorts of concepts