The HYDRO tab holds the editing tools (e.g. cut, merge, relink etc). You will recognize many of from other GIS softwares but here are also some WHIST specific tools and some will also be simpler and faster in WHIST.
- 10.1 Overview of editing tabs
10.2 Subbasin/polygon adjustments (Edit 1)
- 10.2.1 Cut (manual)
- 10.2.2 Split (according to flow accumulation grid)
- 10.2.3 Fill up (fill holes between subbasins)
- 10.2.4 Remove holes (within a subbasin)
- 10.2.5 Reset pour-, target-, center points
- 10.2.6 Correct Fragmentation
- 10.2.7 Kill (delete subbasins)
- 10.2.8 Mururoa (delete subbasins of certain size)
- 10.2.9 Remove empty basins (with no size)
- 10.2.10 Check unfinished
- 10.2.11 Force finish
- 10.2.12 Set category
- 10.2.13 Set protected
- 10.3 Routing/Linking adjustments (Edit 2)
- 10.4 Merging tools with different criterias (Merge)
10.1 Overview of editing tabs
Five tabs are available under the HYDRO tab and there are one for adjustments and correction of delineation (1.), one for routing/linking corrections (2.), one for different types of merging (3.), one for export of different types of shapefiles and stextfiles (4.) and finally one for extraction and connection of data from other sources to the subbasins (5.).
Note: The editing tools will not work on the so called protected basins. If you want to change these you will have to uncheck "respect protected basins under basin/Advanced settings/ in the main menu (top left).
10.2 Subbasin/polygon adjustments (Edit 1)
10.2.1 Cut (manual)
- Go to HYDRO/Edit1
- Activate the cut button (turn red)
- Click on the basin you want to cut, a red box will show up around the subbasin.
- Click just outside the red box and draw the cutting line and end outside the box, the subbasin will be cut.
- Check that routing still OK(e.g. show flowlines)
10.2.2 Split (according to flow accumulation grid)
- Go to HYDRO/Edit1
- Activate the split button (turn red)
- Click on the subbasin you want to split (if the automatic zooming disturbs, uncheck "zoom to selected basin" in the small window that appears).
- Click on the pixel in the flow accumulation grid where you want the split to be processed.
- Click yes to "ok to split?" and the splitting will be done.
- Check that routing and pourpoints are OK after the split. Make it as a standard postprocessing to "split" to always do an "autolink" and a "clean hydro connections" of the subbasins involved in the split.
If you want to split the subbasin with the aim to fit an outlet to a hydrological feature (gauging station, lake, village, etc) you can be helped by viewing a shapefile of the feature location in the background. You can view a shapefile if you follow these instructions **View Shapefiles and Open Street Map
10.2.3 Fill up (fill holes between subbasins)
- Select the subbasins around the hole.
- Click on the button "Fill up".
10.2.4 Remove holes (within a subbasin)
- select the subbasin with the hole
- click on Edit 1/more>/remove holes
10.2.5 Reset pour-, target-, center points
- select the subbasins to reset
- click on Edit 1/more>/reset and select method.
10.2.6 Correct Fragmentation
- This tool split multipart polygons into singlepart and give new parts unique SUBIDs.
10.2.7 Kill (delete subbasins)
- The "kill" button will delete all selected subbasins and should be used with caution. WHIST has no "undo" button. You have to start with the procedure from the last save if you do something wrong.
10.2.8 Mururoa (delete subbasins of certain size)
This tool makes it possible to delete main river basins (and their subbasins) smaller than a certain size.
10.2.9 Remove empty basins (with no size)
Sometimes, depending on the quality of the used topography used when developing the subbasins, or if many manual edits have been made, polygons with an ID but no shape will appear. These might disturb exports of files etc and should therefore be removed.
10.2.10 Check unfinished
10.2.11 Force finish
10.2.12 Set category
A tool that can set the category of your basin. This will be added as an attribute to the subbasin.
10.2.13 Set protected
With "Set protected" selected subbasin can achieve protection status against certain edits. There are several choices:
- Downstream: the subbasin can not be merged with a downstream subbasin.
- Downstream point: change of downstream point is not allowed.
- Upstream: the subbasin can not be merged with upstream subbasins.
- Bothstream: the subbasin can not be merged in any direction.
- Shape: the shape of the subbasin is not allowed to change
- OnlyRouting: the routing and links to and from the subbasins can not be changed.
- None: No protection
10.3 Routing/Linking adjustments (Edit 2)
- If the links between subbasins according to the topography information is known to be wrong or if the routing has become strange due to many edits they maight have to be corrected. This can be made in both manual ways (if the routing should not be in accordance with the topography data) or in automatic way (to follow the given topography).
10.3.1 Links (manual)
- activate the link button (turn red)
- click on the subbasin you want to change direction for
- click on the downstream basin
NOTE! click close to the border to get as natural pour point and pour target as possible, i.e the point from where the upstream subbasin drains and the point within the downstream subbasin that receives the water, respectively.
Autolink can relink selected subbasins in accordance with the topography, e.g. if you have imported subbasins or to correct the routing if many edits have been made which can interrupt and confuse the links. Nowadays there are several options, see figure beneath, and you can for example choose different ways to set pourpoints with or without keeping the routing as it is. This can be useful if you have made manual changes to the routing.
If you are rerouting the subbasins + resetting the pourpoints according to the topography, please use the tool twice. Otherwise not all subbasins may be revised correctly.
10.3.3 Fix hydroloops
- Hydroloops might arise in imported subbasin datasets or after edits. These are fixed by using these tool.
10.3.4 Clean Hydro connections
- The hydro connections might be cut after edits. This tool should always be used to set them again. No change in links will occure.
10.3.5 Select all with default target
- This tool makes it easy to select all subbasins with default targets if they should be checked and perhaps linked to a neighbour instead.
10.3.6 Reset coordinate
With this tool you can reset the different coordinates of a subbasin manually (centerpoint, targetpoint and pourpoint).
10.3.7 Haro id
If you do any routing changes you should reset "Haro id" (Main river basin ID) since this might have changed if there are transbasin changes.
10.4 Merging tools with different criterias (Merge)
There are several ways to merge subbasins. Manual and more automatic based on different criterias.
10.4.1 Merge (using mouse pointer)
- activate the merge button (turn red)
- click on the first basin and then on the second and the subbasins will be merged (an arrow will be seen between the two which will be merged).
10.4.2 Merge by dialog
- by using the dialog it is possible to merge neighbours with the same categories and no upstream or downstream basins, e.g. very small subbasins along the coast, or many small neighbouring sinks that could be merged into one.
10.4.3 Merge selected
- merge all selected basins into one subbasin.
10.4.4 Merge coast
- merge coast merge subbasins with the category "coast". The merging will be processed on selected subbasins according to the settings under HYDRO/create/edit - Method settings.
10.4.5 Merge islands
- if small islands are not necessary to model as single objects they can be grouped by this tool by using the following dialogs for size threshold and range.
10.4.6 Merge with small Upstreams & Downstreams
- These tools will merge non protected basins with upstream and downstream subbasins smaller than a certain limit, respectively.
- This tool is very useful after creation of subbasins to achieve a more narrow size distribution since some small subbasins will appear.