Flood Viewer

Flood Viewer is an easy to use, dependable, interactive data viewing tool. It can be used to provide rapid access to historic/predictive flood extent mapping in an emergency situation (e.g. control room). Alternatively, it provides a simple method for disseminating interactive flood maps to multiple clients without the need to provide them all with bespoke software.

Flood viewer runs within the user’s web browser and can be accessed from USB stick or over the web with no requirement for expensive GIS software and no issues with IT compatibility. In addition to basic GIS viewing functions it incorporates a slider for the user to move seamlessly between different flooding scenarios (e.g. return period events, time).

Flood Viewer data can be defined locally (i.e. on your desktop) or can be uploaded and stored in a Flood Modeller provided cloud location. Data stored in the cloud location will be secure, only accessible to those you share the uniquely generated URL with. Furthermore, data will only remain on the cloud for a maximum of 30 days, after which it will be automatically deleted (you still have the option of uploading the same data again from your Flood Viewer project).

To view your data with Flood Viewer you need to define a new Flood Viewer project. This consists of some or all of the following:

• One or multiple polygon shapefiles representing flood extent outlines, e.g. results from different storm event simulations

• (Optional): Additional shapefiles to represent underlying key locations, e.g. points or polygons representing the location of water level gauge (linked to the Flood Viewer slider) or the location of critical buildings, e.g. hospitals, schools, etc.

• (Optional): Background map layers (as jpg or png georeferenced image files). Note that these are only compatible with the desktop output option. You can use local image tiles as an alternative to selecting the option to download background map tiles (from a Flood Modeller provided online repository).

If you generate a desktop Flood Viewer project, these data are accompanied by an index file (html format) that defines how the layers are displayed. The data can be viewed simply by opening the index file within your designated internet browser, e.g. Internet Explorer or Firefox. However, no internet connection or software installation is required in order for Flood Viewer to work.

If you generate an online Flood Viewer project the Flood Viewer interface presents a URL for you to either copy and distribute or click on to open.

Flood Modeller provides an interface to construct a Flood Viewer index file. This interface enables you to load up the series of flood map data and any background maps or additional shapefiles. These data can then be customised to define how they will appear within a new Flood Viewer project. The following steps explain how to use this interface:

1. Prepare your flood map datasets. This guidance assumes that you have already prepared a series of flood maps (for different scenarios, e.g. storm events) as outline shape files. This may have been done by processing your hydraulic model data in Flood Modeller (using the 1D and 2D flood map calculator tools) or they may have been generated externally (in a GIS software system) or may have been obtained from historic records.

   If your flood maps are defined in ascii grid format you can utilise the Layer Convertor tool to convert these data into outline polygon shapefiles in the Grid Tools section of the Toolbox.

2. If your flood map layers have been generated externally from Flood Modeller then you can use the Add GIS Data button (Home or Map Tools tabs of the main toolbar) to browse to and load these data into the Flood Modeller interface. Alternatively, the Flood Viewer interface also provides a facility to browse to add data. Note that Flood Viewer requires flood map data in ESRI shapefile format (background layers to be included in the project can be shapefiles or geo-image files, i.e. jpeg or png formats).

   

3. Select the Flood Viewer tool by clicking on the button provided in the Map Tools tab of the main toolbar.

   

4. A new window will appear, as shown below:

   

   The window will be automatically populated with any polygon shapefiles present in the Layers list of your current Flood Modeller project (which the tool assumes to be representing different flood outlines). Layers can be removed from or added to this list.

   You are then required to complete the following fields:

   • Output option – this can be online (the default option) or desktop. The online version will be sufficient in most cases. It is quick to generate an online Flood Viewer project, which then utilises online mapping (either street map or satellite imagery  – data provided by Open Street Map) to provide seamless background mapping. If you wish to allow users to access a Flood Viewer project while offline (still using their internet browser) or if you have background images to include in your project then the desktop version will be required. This will download required map tiles and store them within your specified Flood Viewer output folder.

   • Reference – you need to give your Flood Viewer project a reference. Note that, for the desktop version, this will also be used to define a sub-folder name for this project’s data in your specified output folder (sub-folder name is ‘FV_Reference’).

   • Water levels (numeric value or flood map order) – for each flood map included in your Flood Viewer project you must define either an associated numeric water level (i.e. the level reached at the specified gauge location during the flood event) or a ranking order. This value will define the order your flood map layers are added to the sliding scale of your Flood Viewer project. The options to define an exact numeric level or a ranking order are selected above the table (right hand side of interface). Note when ordering the flood map layers, you can use the mouse to drag a row up or down the order (when typing in gauge values or order positions re-ordering is automatic after each entry is completed).

   

5. In addition, all shapefiles (points, lines and polygons) and image files (JPEG or PNG formats), i.e. file types compatible with Flood Viewer, are loaded into the ‘Additional Layers’ table, accessed by clicking the Additional Layers tab on the main interface. The types of data you may add to your project here will be:

   • Any georeferenced image layers in your Flood Modeller view that you wish to include as background layers of your Flood Viewer project. Note these will currently only display in a desktop Flood Viewer project.

   • Additional shape files to show locations of key sites, e.g. hospitals and schools, in your Flood Viewer project (relative to your flood map areas)

   Ensure these extra layers appear in the Additional Layers table and the associated box in the Include column is ticked. You can also add your own name to each layer (to replace the default name which is the filename). An Add Layer button is provided to enable you to add a new layer to the table (i.e. that is not loaded in your map view).

   

   Note the flood outlines are also loaded again here, though in most cases you won’t need these here. Therefore, you can either leave them unchecked, so they don’t filter through to the Flood Viewer project you will generate, or highlight these rows and click the Remove Layer button (below the table) to delete them from the Additional Layers table.

6. You can set some display properties for the non-flood map layers you specify in your project. Highlight a row in the Additional Layers table and click the Edit Shape Property button located below the table. This will display a new window in which you can define certain display settings that will be applied for the layer in your Flood Viewer project (see below). Depending on the selected layer, not all settings will be applicable (e.g. line thickness for a point shape file) and so some settings may be disabled. In addition to colour, thickness and transparency level you can select whether the layer will be automatically visible when your new Flood Viewer project starts up. Note the default setting is for all additional layers to not be visible.

   

7. If you are creating a desktop Flood Viewer project then there are some additional settings that will only become enabled when the desktop option is selected. These are:

   • If you are loading data for a location in the UK then you can select the map tiles download option (we only have UK tiles available on our server at the moment). This function will then automatically download background map tiles for the local region of your flood map data and add these to your Flood Viewer project. Note that in some cases your local security settings may prevent you accessing these data.

   • Output folder – specify a location where your new Flood Viewer project will be created (in the sub-folder defined above). Note that if your defined folder does not exist then the tool will create it. If your project is going to use the same downloaded background map tiles (UK projects only) as an existing project on your system then choose the same output folder as used for this. The Flood Viewer interface will then not download your map tiles a second time and instead let your new project share the same map tiles as your existing project. The default location for your output folder is always a Flood Viewer sub-folder in your documents area.

8. There are other options provided to define how your Flood Viewer project is generated. These are as follows:

   1. Flood map colour and transparency settings – these settings are under the title Graphic Options. All flood maps added to your project will display the same colour, which can be set by typing in a colour code or selecting from the palette provided (under the adjacent button). The transparency level is a number between 0 and 1 (where 1 is fully transparent, i.e. not visible)

   2. Display output folder upon completion – selecting this option will open a Windows browser window showing the contents of your new desktop Flood Viewer project folder (disabled for online Flood Viewer projects).

   3. Create desktop shortcut – creates a shortcut that opens your new Flood Viewer project (in your internet browser). Note in some operating systems this shortcut may fail to generate.

   4. Copy link to Flood Viewer into clipboard – the path or URL to your Flood Viewer project can then be pasted into an email to disseminate to others (e.g. if your project is created on a shared network).

   

9. When all settings are defined click the OK button to define your new Flood Viewer project. If you are downloading background map tiles this process may take a few minutes. If you are just using your own local data, the process will be very fast. When the project is created:

   • The URL for your online Flood Viewer project will appear in the lower left corner of the interface (as shown in the example below). Click on this link to access in your default web browser

     

   • Desktop Flood Viewer projects will automatically open in your default internet browser.

   • Note that, for desktop Flood Viewer projects, you may have to manually instruct your browser to bypass its security settings related to the running of scripts. If you see the following message in your web browser (and no data are displayed) then select the Allow Blocked Content option. Your Flood Viewer project should then open.

     

10. When your Flood Viewer project opens you should see something like the examples below in your web browser:

    Online version:

    

    Desktop version:

    

    Slider is between gauge heights referenced to the loaded flood maps:

    • Gauge height = 11.7m

    • Displayed on map are both flood outlines 20yr RP and 50yr RP

    • The flood outline 20yr RP is shown fully opaque

    • The flood outline 50yr RP is shown partially transparent as there is uncertainty in this region over whether flooding will occur or not (as we are between modelled gauge levels).

11. The Flood Viewer display includes the following controls for you to further manipulate the view:

    Zooming

    You can move around the map by dragging, and zoom in and out with either the buttons in the top-right of the screen or your mouse’s scroll wheel. Flood Viewer will use any maps available in the project’s map tiles folder.

    

    Layers and current cursor position

    Online version:

    

    Desktop version:

    

    Gaugeboard

    

    Adobe Flash Security Settings

    The desktop version of Flood Viewer uses Adobe Flash to display the specified flood extent data. Recent changes to the Adobe default security settings no longer allow local content, i.e. content created on your machine such as a Flood Viewer project, to load automatically. To get around this issue you need to access and change the Adobe Settings as follows:

    1. When you load a Flood Viewer project into your web browser you will likely see the page “hang” with only the Flood Viewer logo displayed (if an “Allow blocked content” prompt appears first then click Allow to proceed). Right-click on the centre of the page. You should see an Adobe menu. Select "Global Settings".

    2. You should see a new window pop-up after a few seconds, entitled Flash Player Settings Manager (in Chrome these menus may appear in a new tab instead). Select the "Advanced" tab (in the pop-up window) or Global Security Settings (in the separate tab).

    3. Next, in the pop-up window, click the button called "Trusted location settings" or in the separate tab, click on “Edit Locations”. This will display another window that allows you to add files or folder names to a list of local places that Adobe will allow data to be loaded from. Use the Add or Browse buttons to browse to your Flood Viewer project location and add this folder to the list. Note that you can add a higher folder as Adobe should then accept anything in any sub-folders from this.

    4. After making the above changes to settings close down all the Adobe Settings windows or tabs and then refresh the Flood Viewer page in your browser. Hopefully it will then load successfully after a few seconds.