Project 2

Objective

To create a map that shows commercial development in Baltimore, MD over the last century, both spatially and temporally.

Process

Using the Real_Property dataset I wrote a python code designed to:
1. Add in the Real_Property Layer
2. Change the fill color to gray
3. Update the layer tree
4. perform a selection commercial lots present during the desired time period in twenty year increments.
5. Save this selection to file as a new Shapefiles
6. Add the new shapefile to the map.
That code is as follows:

Real_Property = QgsVectorLayer('C:/Users/ges_student/Desktop/Project_2/Shapefiles/Real_Property_Proj.gpkg', 'Real_Property')
Real_Property.isValid()
# Should Return "True"
QgsProject.instance().addMapLayer(Real_Property)
# Should return "<qgis._core.QgsVectorLayer object at 0x000001714E5500D8>"

renderer = Real_Property.renderer()
renderer
#Should return "<qgis._core.QgsSingleSymbolRenderer object at 0x000001F6CBC06DC8>"
symbol = renderer.symbol()
symbol.dump()
#Should return 'FILL SYMBOL (1 layers) color 152,125,183,255'
symbol.setColor(Qt.gray)
Real_Property.triggerRepaint()

layer_tree = iface.layerTreeView()
layer_tree.refreshLayerSymbology(Real_Property.id())

selection = Real_Property.getFeatures(QgsFeatureRequest(). setFilterExpression(u'"YEAR_BUILD" >= 1900 and "YEAR_BUILD" <= 2018 and "USEGROUP" = \'C\''))
Real_Property.selectByIds([s.id() for s in selection])
iface.mapCanvas().zoomToSelected()

QgsVectorFileWriter.writeAsVectorFormat(Real_Property, r'C:/Users/ges_student/Desktop/Project_2/Shapefiles/Comm_Poly_Test2.gpkg', 'utf-8', Real_Property.crs(),'GPKG', True)

Comm_Poly_Test2 = QgsVectorLayer('C:/Users/ges_student/Desktop/Project_2/Shapefiles/Comm_Poly_Test2.gpkg', 'Real_Property')
Comm_Poly_Test2.isValid()
# Should Return "True"
QgsProject.instance().addMapLayer(Comm_Poly_Test2)

The individual components of the code are shown below:

Add in the Real_Property Layer

Real_Property = QgsVectorLayer('C:/Users/ges_student/Desktop/Project_2/Shapefiles/Real_Property_Proj.gpkg', 'Real_Property')
Real_Property.isValid()
# Should Return "True"
QgsProject.instance().addMapLayer(Real_Property)
# Should return "<qgis._core.QgsVectorLayer object at 0x000001714E5500D8>"

Change the fill color to gray

renderer = Real_Property.renderer()
renderer
#Should return "<qgis._core.QgsSingleSymbolRenderer object at 0x000001F6CBC06DC8>"
symbol = renderer.symbol()
symbol.dump()
#Should return 'FILL SYMBOL (1 layers) color 152,125,183,255'
symbol.setColor(Qt.gray)
Real_Property.triggerRepaint()

Update the layer tree

layer_tree = iface.layerTreeView()
layer_tree.refreshLayerSymbology(Real_Property.id())

perform a selection commercial lots present during the desired time period in twenty year increments.

selection = Real_Property.getFeatures(QgsFeatureRequest(). setFilterExpression(u'"YEAR_BUILD" >= 1900 and "YEAR_BUILD" <= 2018 and "USEGROUP" = \'C\''))
Real_Property.selectByIds([s.id() for s in selection])
iface.mapCanvas().zoomToSelected()

Script Selection alt text

Save this selection to file as a new Shapefiles

QgsVectorFileWriter.writeAsVectorFormat(Real_Property, r'C:/Users/ges_student/Desktop/Project_2/Shapefiles/Comm_Poly_Test2.gpkg', 'utf-8', Real_Property.crs(),'GPKG', True)

Add the new shapefile to the map.

Comm_Poly_Test2 = QgsVectorLayer('C:/Users/ges_student/Desktop/Project_2/Shapefiles/Comm_Poly_Test2.gpkg', 'Real_Property')
Comm_Poly_Test2.isValid()
# Should Return "True"
QgsProject.instance().addMapLayer(Comm_Poly_Test2)

New Layer Addition alt text

From this layer I also created centroids of each polygon.
Next I performed a kernel analysis resulting a heatmap of commercial development for each time period.

Results

By creating shapefiles for commercial properties in twenty year increments and overlaying them on top of the Real_Property Layer, I was able to make a map that displays not only the spatial pattern of commercial development, but also the temporal pattern by assigning a graduated red to yellow scale in which older commercial properties are red, newer properties in yellow.
From this, I was able to use Adobe Photoshop to create a GIF that animates the development process over time and space in Baltimore.

alt text

To create a three-dimensional view of this process, I used these same shapefiles to similarly create an animated GIF of the same commercial development patterns in QGIS 3D map view, using a Baltimore elevation data as the base raster.

alt text

Lastly, as a unique and different way of visualizing commercial development, both spatially and temporally, I used the heatmaps created by the kernel analysis in QGIS 3D map view and selected them as the elevation raster to be used.
This essentially results in displaying commercial density as elevation in the three-dimensional view.

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