School of Geography FACULTY OF ENVIRONMENT School of Geography FACULTY OF ENVIRONMENT GEOG5060 GIS & Environment Dr Steve Carver

School of Geography FACULTY OF ENVIRONMENT Andy Turner Lecture 7: Terrain modelling – geomorphometrics

School of Geography FACULTY OF ENVIRONMENT Course Component Lecture Workshop Practical Assignment Assessment

School of Geography FACULTY OF ENVIRONMENT Introduction Basic metrics Equidistant orthogonal comparisons Other geomorphometrics State of play Lecture Outline

School of Geography FACULTY OF ENVIRONMENT Assignment This part of the course is about working together to improve our teaching and research on geomorphometrics During the lecture consider areas in which you could address some of the gaps I will mention I am asking you to contribute and develop this part of the course Your contribution really could be anything! I am also keen for you to collaborate and work together in groups or en masse

School of Geography FACULTY OF ENVIRONMENT Some assignment ideas Update wikipedia or other encyclopedia type web content Improve course materials Contribute a research article based on applied or investigative work Develop software Results visualiser Graphical User Interface

School of Geography FACULTY OF ENVIRONMENT Definition Geomorphometrics are measures of the state and change in surface geometry of geophysical horizons. They are topographic measures that can be used in terrain analysis and geographical modelling. rphometrics/ rphometrics/

School of Geography FACULTY OF ENVIRONMENT Apologies and acknowledgement Last night I spent hours developing these lecture slides only to lose most of the work I am probably more annoyed by this than you will be Hopefully you won’t suffer as much as me as a consequence What follows are some slides developed by some in the class of 2007 with a new template applied and jiggled around a bit so you can see all the various images and text.

School of Geography FACULTY OF ENVIRONMENT Last 2 Lectures Terrain analysis 1 DEMs and DTMs derived variables example applications Terrain analysis 2 access modelling landscape evaluation hazard mapping heightslopeaspect hillshading plan curvature Feature extraction

School of Geography FACULTY OF ENVIRONMENT Origins Peter Fisher Peakiness Development of a grids package The SPIN!-project MedAction, DesertLinks and tempQsim Desire for greater flexibility, capability and freedom than that offered by commercial proprietary GIS

School of Geography FACULTY OF ENVIRONMENT Overview So what are geomorphometrics? Measures of the relative heights of the land of the earth’s surface to allow comparison of: Topography Terrain analysis e.g. how peaky is an area? Surface geometry of the earth.

School of Geography FACULTY OF ENVIRONMENT Raster Elevation Data DEM data interpolated from vector data Widely available for many planets and regions of Earth SRTM 3 arc secs Publicly available OS 10 metre Available via chest LIDAR 2 meter Available but unlicensed Getting better all the time Uncertainties abound

School of Geography FACULTY OF ENVIRONMENT Example DEM Red areas indicate high altitude, green low altitude

School of Geography FACULTY OF ENVIRONMENT Future DEMs Higher spatial resolution Larger regions More values Larger ranges More detailed precision 3D spatial Temporal change Hundreds of thousands of millions of data points

School of Geography FACULTY OF ENVIRONMENT Data pre-processing One of the first things to do is to be able to process all this data Grids 1.0 beta Clean the data Mask Are there any holes? How can we cope best with these

School of Geography FACULTY OF ENVIRONMENT Define the river basins, catchments and HRUs for the DEM Develop land degradation risk indicators Erosion Salinity Develop a fully distributed hydrological model Data pre-processing continued...

School of Geography FACULTY OF ENVIRONMENT Geomorphometrics compare relative heights of cells Allowing comparison of terrain, topology Uncertainty is always present Recap

School of Geography FACULTY OF ENVIRONMENT Slopeyness Basic metrics

School of Geography FACULTY OF ENVIRONMENT Can any one suggest the name of another basic geomorphometric? Question

School of Geography FACULTY OF ENVIRONMENT Slope is the gradient of an area and aspect is the angle to a particular orientation over a given region Slope and Aspect

School of Geography FACULTY OF ENVIRONMENT Slopyness Upness Downess Flatness Roughness Flatness calculated for the 2 cell neighbourhood Other metrics

School of Geography FACULTY OF ENVIRONMENT Circular region using equidistant orthoganal comparisons Vector addition Distance weighting Scale NB From the model output white regions indicate areas of high values for that metric What region? How to calculate it?

School of Geography FACULTY OF ENVIRONMENT Slope – 13 cell neighbourhood

School of Geography FACULTY OF ENVIRONMENT Slope – 49 cell neighbourhood

School of Geography FACULTY OF ENVIRONMENT Slope 8

School of Geography FACULTY OF ENVIRONMENT Aspect 2

School of Geography FACULTY OF ENVIRONMENT Aspect 4

School of Geography FACULTY OF ENVIRONMENT Aspect 8

School of Geography FACULTY OF ENVIRONMENT Distance weighting Differencing to focus on nid-scales can be done directly by applying a more complex spatial weighting scheme Only relevant for some measures Not aspect What about upness and downness? Scale and distance weighting

School of Geography FACULTY OF ENVIRONMENT Equidistant orthogonal comparisons Rotation invariant metrics B4 A4 E3 D4 C4 D3 B3 E4 A3E2 C3 * C1 A1B1 D1 C2 D2 E1 A2 B2.A.. BCB. AC X CA. BCB..A. For each metric, compare each orthoganal set within a region What is observed? hhhh, hhhl, hhll, llhl hlll, llll

School of Geography FACULTY OF ENVIRONMENT Axis based metrics B4 A4 E3 D4 C4 D3 B3 E4 A3E2 C3 * C1 A1B1 D1 C2 D2 E1 A2 B2

School of Geography FACULTY OF ENVIRONMENT H L r H L H L r L H HHLL / LHHL / HLLH HLHL / LHLH

School of Geography FACULTY OF ENVIRONMENT HHHL - saddle

School of Geography FACULTY OF ENVIRONMENT HHHH - crater

School of Geography FACULTY OF ENVIRONMENT Geog 5060 GIS & Environment Lecture 7 HHLL - slope

School of Geography FACULTY OF ENVIRONMENT LLLL - peak

School of Geography FACULTY OF ENVIRONMENT How to treat cells with the same height? How to treat cells with no data value? What conditioners are appropriate? Two types of weight Distance weighting Difference in elevation weighting What is best? Considerations

School of Geography FACULTY OF ENVIRONMENT Example 1: w_hhll

School of Geography FACULTY OF ENVIRONMENT Example 4: sumd_abs_xlxh_ai_lllh

School of Geography FACULTY OF ENVIRONMENT Profile or Contour Concavity or Convexity Convergence or Divergence B4 A4 E3 D4 C4 D3 B3 E4 A3E2 C3 * C1 A1B1 D1 C2 D2 E1 A2 B2 Axis based metrics

School of Geography FACULTY OF ENVIRONMENT What other interesting metrics? minimum type profile concavity maximum type profile convexity Better for identifying features? Probably best in combination with the other metrics Sorry, no examples! Considerations

School of Geography FACULTY OF ENVIRONMENT Other geomorphometrics Up and down slope type geomorphometrics Upslope area Complex distance weighting More hydrological type metrics Flow accumulation Visibility based metrics Monte Carlo type uncertainty of all

School of Geography FACULTY OF ENVIRONMENT Proprietary or closed source Commercial Research LandSerf TauDEM Open source GMT Grids Software

School of Geography FACULTY OF ENVIRONMENT Summary Basic metrics Equidistant orthogonal comparisons Scale and distance weighting Rotation invariant metrics Scale and distance weighting - uncertainty

School of Geography FACULTY OF ENVIRONMENT Next Steps Practical Experiment with a program to generate geomorphometrics in teams Friday 12:00 to 16:00 in Masters computing room, Geography East Building. Develop an output of some sort and explain the processes you went through to produce it. Assignment Show understanding of geomorphometrics and develop the subject

School of Geography FACULTY OF ENVIRONMENT Next week… Hydrological modelling 1: catchment models Basics of hydrology Creating hydrologically correct DEMs Modelling catchment variables Workshop: Catchment modelling in GRID Practical: Catchment modelling