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Data_Analysis

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webbhm edited this page Oct 23, 2018 · 1 revision

Data Analysis

QGis will be used for analysis, though other GIS programs can be used for the same processing.

Base Maps

Go into Web/QuickMapServices and select the OSM (Open Street Map) OSM Standard map for background. This will give you an approximate image of the lake for general purposes. It is also useful to load several historical USGS maps for information about Lake Monroe before the dam was built and the lake was filled. Some of the maps to use are:

  • IN_Allens Creek_159481_1957_24000_geo.pdf
  • IN_Clear Creek_159619_1956_24000_geo.pdf
  • IN_Elkinsville_156890_1950_24000_geo.pdf These can be pulled into QGis via Layer/Add Raster Layer and adding the file. After loading, go to the properties and set the opacity to about 30%.

Vector Data (csv files)

  • Go to Layer/Add Layer/Delimited Text Layer and select the file
  • Name the layer
  • Determine if the first line is header information, and if any lines should be skipped (ie there is meta-data)
  • Check that the Lat/Lon are correctly in the X/Y fields
  • Check that the geometry is WGS 84
  • Click Add and wait for the data to appear.

You can play around with the properties for interesting display.

  • Change the symbology to "Graduated"
  • Under "Symbol" select the "Simple Marker", then under "Stroke Color" change it to "Transparent Stroke", then "OK". Without this the black outline of the symbol will dominate and it will look like a black line.
  • Set the color ramp, "Spectral" is my standard choice.
  • For quick output, just hit "Classify" and accept the grouping that the system provides.
  • Press "Apply" then "Ok"

At some point it is best to: Vector/Data Management Tools/Merge Vector Layers This puts all data into one dataset, so that classified symbology is consistent across all the data, it may be worth the effort at this time to set the classiications to 5 or 10 ft intervals.

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