|
|
|
|
|
|
|
|
|
|
|
 |
| Installation & Copyright | About the GREAT-ER model | Running GREAT-ER | Creating new catchments | Results & Interpretation | Miscellaneous | |
Results & Interpretation
Q: What are the GREAT-ER outputs?
Q: How should I interpret the GREAT-ER map output before simulation?
Q: How can I modify the maps?
Q: How can I get some information on map themes (rivers, discharge sites, background data, etc.)?
Q: How should I interpret the GREAT-ER map output after simulation?
Q: How can I change the colour-coded classes on a map?
Q: How can I class discharge sites according to the concentration of the tested substance?
Q: How can I visualise the effect of catchments treatment plants?
Q: How can I visualise a risk assessment for a substance?
Q: What is a river profile? How can I edit it?
Q: Why do I only see a part of the points if I make a river profile? How can I see the distribution on the entire river?
Q: What is the meaning of different PECcatchment results?
Q: How can I export results to a report (e.g. Word or PowerPoint)?
- How can I export a map?
- How can I export the original data (chemical, model, catchments, etc.) and analysis results?
- How can I export a river profile?
Q: What are the GREAT-ER outputs?
A: The results of a simulation can be displayed as colour-coded river stretches on a map or concentration profiles along a river. Moreover, you can add some background data, pictures or monitoring data on top of the maps. GREAT-ER provides users with several options to analyse the results and derive further values from them.
Q: How should I interpret the GREAT-ER map output before simulation?
A: When you start a new scenario, GREAT-ER presents the catchment as a default map with several characteristics as mentioned in the views table of content (to the left of the map): the catchment boundary; the discharge sites as black dots; the river network as thin blue lines; and, sewage discharge connections as thin red lines. You can modify this presentation using the Display menu.
Q: How can I modify the maps?
You can change the size of the map using Zoom in, Zoom out or Full Catchment Extent; these commands are also available as buttons in tool bar. Other themes might be added on the default map: Background data such as Roads, railroads, city areas and city names (using Add Background Date and Remove Background Data); the mean river flow might be represented by different line thickness selecting Show River Flows. The Select Rivernet by Flow command allows users to reduce the number of displayed river segments using the criterion of minimal flow. You can add or remove themes by checking or un-checking these different parameters in the views table of content. If you want to remove all the added parameters, you can select Remove themes in the Display menu. For more information, see the Display chapter of the tutorial (pages 51-54) in the GREAT-ER User Manual (1557 Kb).
Q: How can I get some information on map themes (rivers, discharge sites, background data, etc.)?
A: You can use the Identify tool by selecting Identify in the Display menu or the corresponding button in the tool bar. The mouse pointer will change its shape and if you click anywhere in a view, attributes of features of all active themes are displayed in several (subsequent) dialogs. Moreover, some catchments offer site pictures. If you select Show Site Pictures in the Display menu, the mouse pointer will change its shape and the locations at which pictures have been taken are marked with large active dots.
Q: How should I interpret the GREAT-ER map output after simulation?
A: After simulation, the rivers stretches are coloured according to the model results. A new theme is also visible in the views table of content on the left of the screen. The default presented parameter is Csim mean for simulated concentration; mean indicates that the different colours represent the mean concentrations resulting from the Monte Carlo method. By default, 4 colour-coded classes are presented, corresponding to different percentile classes (0-25%, 25-50%, 50-75% and 75-100%).
Q: How can I change the colour-coded classes on a map?
A: After a model run has been completed, the results are stored as frequency distribution. It is then possible to calculate percentiles of concentrations for the different river stretches and present the results as colour-coded classes on a map. By default, 4 colour-coded classes were presented, corresponding to different percentile classes (0-25%, 25-50%, 50-75% and 75-100%). Nevertheless, you can modify the presentation of the results using Csim Classes River item in the Analysis menu. You can then define new colour-coded classes (number and percentiles limits). You can also combine these classes with the mean flow by strech width using Combine Csim/Flow item of the Analysis menu. For more information, please read pages 45-50 of the GREAT-ER User Manual (1557 Kb).
Q: How can I class discharge sites according to the concentration of the tested substance?
A: The GREAT-ER models calculate concentration distributions for the influent and effluent of the catchments treatment plants. Using Discharge Influent Csim or Discharge Effluent Csim items of the Analysis menu, you can display the discharge sites classified as colour-coded classes by either influent or effluent concentration.
Q: How can I visualise the effect of catchments treatment plants?
A: Using Discharge Influent Csim or Discharge Effluent Csim items of the Analysis menu, you can display the discharge sites classified as colour-coded classes by either influent or effluent concentration. You can have a good indication of the effect of the treatment plant by comparing these two concentrations. Moreover, the model results for treatment plants can be investigated using the identify tool.
Q: How can I visualise a risk assessment for a substance?
A: A possible way to present the results is to change the colour-coded classes on the basis of PNEC values: the first class (in green) being the Csim values lower than PNEC and the second one (in red) being the Csim values above the PNEC.
Q: What is a river profile? How can I edit it?
A: A river profile is Csim, (internal values) collected, moving downstream from a selected stretch. It is displayed in a simple X/Y-chart. To obtain this chart, you have to select Profile item in the Analysis Menu. The cursor shape changes to identify the new mode and you then have to select a stretch by clicking on the map view. You have to notice that the presented profile might not display all stretches downstream from the selected stretch. To deal with this limitation, see the question Why do I only see a part of the points if I make a river profile? How can I see the distribution on the entire river? below.
Q: Why do I only see a part of the points if I make a river profile? How can I see the distribution on the entire river?
A: This is a consequence of the limitations of the chart option of ArcView. Only 50 data points can be displayed within an X/Y plot. For a complete river profile and a more convenient graphic presentation, you can export the data to e.g. Excel: Select Export Profile item in the Analysis menu to save the original data of the profile in .txt format. Open this file with Excel to draw your graphs.
Q: What is the meaning of different PECcatchment results?
A: PECcatchment is a new concept for geo-referenced exposure assessment. Therefore, 5 PECcatchment values are calculated by GREAT-ER (by different weight and stretch selection) in order to demonstrate the effect of using different definitions.
- The calculation can take into account all the stretches within a catchment or only the polluted ones.
- The PECcatchment can be weighted by stretch volume (placing more weight on large rivers), by stretch length (small rivers being considered to be equally valuable as large ones) or by flow increment (The weighting of a stretch is calculated by the difference of flow in relation to its upstream stretches; this value is only considered for all streches within a catchment).
For further information, read the #8 contribution to GREAT-ER (Boeije et al., 2000, Chemosphere, 40, 255-265; (list of publications (11 Kb)).
Q: How can I export results to a report (e.g. Word or PowerPoint)?
- How can I export a map?
A: The easiest way is to use the Print Screen button on your keyboard and then Paste in a windows document (e.g. Word or PowerPoint). Another solution is to shift to Expert Mode (select Expert Mode in the GREAT-ER menu) and to select Export in the File menu to save the map as a picture file (Placeable WMF, Windows BITMAP, etc.) These files are easy to insert in windows documents.
- How can I export the original data (chemical, model, catchments, etc.) and analysis results?
A: A report in .txt format can be obtained by the selection of Report in the GREAT-ER menu. This file contains all the information used for the simulation (identification and properties of the substance; the selected model and its parameters; environmental parameters; river data; etc.) and then analysis results (PEC initial, PECcatchment, etc.)
- How can I export a river profile?
A: You have to select Export Profile in the Analysis menu to save the original data of the profile in .txt format. You can then open this file with Excel and redraw your graph.