For most SCALGO Live layers, the underlying data can be easily and
quickly downloaded. Look for the grey down arrow to the left of the layer
name which indicates that you have download access to that
particular layer. To download data, use the following process:
Select the download tool in
the top of the layer selection menu.
Select the area you want to download; you can select either a
simple rectangle, or draw an arbitrary polygon. In the latter case,
single-clicking starts the drawing of the polygon and adds new
vertices, double-clicking ends the drawing.
Select your file format in the dialog for the type of data you are downloading
(raster, aerial or vector), or leave the defaults in place.
Hit the download icon next to the layer
you want to download. If the icon does not appear, the particular
layer you have selected is not available for download.
The underlying data will be downloaded in its native resolution and
projection. Thus, be aware that large selections can result in very
large downloads for high-resolution data sets. See the video below for
a demonstration of the download process.
Demonstration of the process of
downloading raster and vector datasets, and how to select the
format to use.
For certain raster-based flooding layers (e.g. sea-level rise, flooded
areas of a Flash Flood Map, etc.), flood masks can be downloaded as
simplified polygons, ready for use in end-user GIS tools such as MapInfo,
or as a basis for automated vector-based risk analysis and
To download a mask polygon, select the "Vector"
option in the dialog box shown after hitting the download icon
to an applicable layer. Additional options allow customization of the vectorization process:
To create a mask, a threshold should be given
determining which values of the raster data are to be covered by the polygons.
For example in case of sea-level rise, a threshold of "3 m" will generate polygons
covering areas flooded during a 3 m sea-level rise event.
Multiple values can be given to generate multiple masks by separating the values
with commas (e.g. setting thresholds to "50 cm, 1 m, 1.5 m" will generate three
polygonal masks called "dataset-0.5", "dataset-1", and
"dataset-1.5" for 0.5, 1, and 1.5 m sea-level rise, respectively).
For some layers, buildings can be automatically "filled in" using raster values
surrounding the buildings, creating a map more suitable for automatic analysis of
flood risk for individual buildings. To enable this, select the "Remove buildings"
option (if applicable). Since this option fills in data within buildings
after the actual analysis, the result should not be used in critical applications.
To make the output easy to import into most end-user GIS applications, all
mask polygons are simplified, removing very small areas and smoothing the
edges of the polygons. The amount of simplification done can be controlled
by choosing the "Simplification level". Available options are "Low", "Medium",
and "High". The higher the simplification level, the smaller and more coarse
the output will be.
Example of 1.34 m sea-level rise (blue area), with a downloaded (and imported) mask polygon in black on top.