ASSIGNMENTS: in class practice and homework
DRAFT-subject to modifications!Introduction Slides Intro
Homework structure to be used for all assignments
(300-600 word report with 1-3 pages of graphics)
- Task, problem, background
- Approach, methodology - general description, no need to repeat step-by-step instructions
- Results: maps, images, graphs, numbers with brief comments
- Discussion: observations in results, method issues, point to problems in assignment
- Conclusion - 1-2 sentences what you have learned
Topic: Data acquisition and integration
Task: Get familiar with tools and data
- List data in the provided database, find their projection, coordinate system, spatial extent, resolution, accuracy and source/mapping technique if available.
- Display and query raster and vector data in 2D, list data attributes.
- Display elevation data and selected vector data in 3D
- Convert raster to vector and vector (point, line, area) to raster
- Post selected data to Google Maps and Google Earth.
Approach:
GRASS solution Section 1,
GRASS solution Section 2
ArcGIS solution Section 1,
ArcGIS solution Section 2
Homework Section I: Prepare 3 page report describing the properties of data in this data set - 1 page text, 2 page screenshots
Homework Section II: Prepare 3 page report discussing GIS data models and their conversion (changing raster resolution, vector data type, raster to vector and vector to raster) - issues, methods, results. 1 page text (min 300 words) 2 page figures.
Topic: Data display and visualization
Task: Create 2D images and 3D views
- Display raster and vector maps with adjusted color tables and symbols, select suitable color tables for continuous and discrete data, histogram equalized colors, custom colors for highlighting features
- Display labels, grids, scales, output hardcopy map
- Interactively view raster and vector data in 3D space, adjust point symbols using attribute values, adjust lighting to highlight features
- Visualize multiple surfaces with cutting planes
Approach: GRASS solution ArcGIS solution
Homework: Prepare series of 2D and 3D images representing SW_Wake county landscape with its natural and man-made features. Demonstrate the use of multiple surfaces for visual analysis of the difference between the 30m NED and SRTM DEM.
Topic: Geospatial Analysis I: global, zonal and focal operations, map algebra
Task: compute summaries, use map algebra to analyze, modify and derive new maps, explain difference between operations on discrete and continuous data
- compute areas for land use classes and lakes
- use neighborhood operations to smooth the SRTM data
- analyze differences between NED and SRTM data
- derive and apply masks
- compute vegetation index
- compute global and zonal statistics for elevation and land use classes
- patch, overlay and rescale raster maps
Approach GRASS solution ArcGIS solution
Getting started with a new project
Homework: Prepare a report that describes the use of global and zonal statistics, neighborhood operations and map algebra to analyze continuous and discrete geospatial data.
Topic: Geospatial Analysis II: reclassification, correlation, buffers, cost surfaces, least cost path
Tasks: use buffers and map algebra to find areas within a given distance from given features (roads, lakes) that have a selected property (are developed), use cost surface analysis to assist in accident management
- reclassify and rescale raster maps, compute correlation between elevation maps
- use buffers around lakes to find neighborhoods within walking distance to a lake or pond
- use buffers along the major roads to find neighborhoods that may be affected by noise pollution.
- assume there was an accident at N,E on Hwy 1. Compute cost surface for getting to the site from any point in the study region using the street map converted to raster. Find which firestation has the lowest cost to get there and find the shortest path. Find the 2nd and 3rd closest station and path. Discuss the issue of interchanges.
- a child got lost around Lake Wheeler - compute the accessibility map to aid the search
Approach GRASS solution ArcGIS solution
Homework: Prepare a report that describes the use of buffers and cost surfaces.
Topic: Geomorphometry I: Terrain modeling
Tasks: Compute DEM and DSM from lidar point data, derive contours from different types of elevation models, compute and visualize TIN elevation model
- analyze multiple return lidar data and create DEM and DSM
- compute appropriate contour interval and derive contours from NED, SRTM, and TIN
- compute TIN using the standard and constrained Delaunay triangulation
Approach GRASS solution ArcGIS solution
Homework: Prepare a report on properties of different types of digital elevation models and methods to create them
Topic: Geomorphometry II: Spatial interpolation and approximation
Tasks: Demonstrate impact of data distribution and interpolation methods on resulting surface using 3D visualization or hillshade
- interpolate DEM to 2m resolution using a subsample of lidar data: compare methods (voronoi diagrams, linear on TIN, IDW, spline, natural neighbor)
- demonstrate impact of spline interpolation parameters on the resulting surface: control level of detail, remove noise, estimate deviations
Approach GRASS solution ArcGIS solution
Homework: Prepare a report on impact of interpolation method and its parameters on the resulting surface
Topic: Geomorphometry III: Spatial and Temporal Terrain analysis
Tasks: Derive topographic parameters and landforms, analyze time series of DEMs
- compare slope, aspect and curvatures derived from NED, SRTM, and TIN
- compute slope, aspect and curvatures from lidar point data using splines with different tension parameters
- derive landforms and extract terrain features by combining basic topographic parameters, discuss impact of resolution
- compute cut and fill volume and change in elevation surface area due to construction
- derive maps characterizing coastal terrain evolution using raster time series analysis
Approach GRASS solution ArcGIS solution
Homework: Prepare report on methods for computing topographic parameters from digital elevation models and discuss how the methods and types of DEM influence the result. Describe results of elevation time series analysis.
Topic: Flow routing, watershed analysis
Tasks: Compare flowaccumulation, stream networks and watersheds derived by different algorithms from different DEMs
- compute and compare streams and watersheds derived from NED and SRTM using D8, SFD with least cost path routing, show impact of exterior watershed threshold
- map DEM depressions
- compute and compare flow accumulation maps derived by D8, Dinf, SFD, MFD
- compute DEM with carved stream and show its impact on flow accumulation map
- extract watershed boundaries for a given outlet
- derive flowlines and flow path length using downslope and upslope flowtracing
- compute flooded area from given seed point at given flood level
Homework:Prepare report that compares different methods for flowrouting and watershed analysis
October 30: Midterm
Topic: Modeling Geospatial Processes: Hydrologic and erosion modeling
Tasks: Compute surface runoff, soil loss and net erosion deposition maps models
- compute wetness index
- compute peak runoff using data derived in GIS and models available in GIS
- compute and compare erosion topographic factor based on hillslope length and on contributing area
- Derive soil erodibility and land cover maps for different land use alternatives
- Compute erosion, sediment transport and deposition for different land use alternatives
- compute runoff for different land use alternatives (create alternatives using Tangible GIS)
GRASS solution , GRASS solution: SIMWE
ArcGIS solution
Slides with GRASS workflow
Homework: Prepare report on hydrologic and erosion modeling using GIS and simulations of impact of various land use alternatives
Topic: Geomorphometry V: Viewshed, solar potential analysis
- compute viewshed area from a building on CC and from RBC tower, compare areas, find visible points of interest, compare the results from SRTM and NED
- investigate visibility from 3 different locations to find a suitable location of webcam for watershed monitoring
- compute cast shadows for a given area with a building for 3 different times on December 22
- compute summary radiation for summer and winter solstice days in a given area
Homework: Prepare report on the results of viewshed computation and solar irradiation mapping