GIS services Development using CloudEO Platform Data and Tools BY DAVID ELISEO MARTINEZEL SALVADOR

Where do landslides happen in El Salvador?

In the volcanic chain, where are located also the main population centers, and in the north mountain chain. The diversity of soil/rocks, topography and climate contribute to the high landslide hazard susceptibility.

When do landslides happen?Only with very specific studies is possible to determine the landslide potential on an area, but it is known that on the rainy season the hazard is higher.In El Salvador, the rainy season goes from May to October and in this period is when most landslides occur.

Source: www.snet.gob.sv

1982

2009

2009

Historical Events

MARN landslide inventory

Concept of the service GIS dynamic visualization of areas that would present a higher landslide susceptibility for early warning systems and available to be consumed from mobile web, desktop and mobile applications.

INPUTS:

•30 m DEM provided by CloudEO

•Rain gauge observations obtained from MARN/SNET web site.

Data preparation: Tools•QGIS to visualize and process the DEM tiles:

Merge DEM tiles and then clip El Salvador extent, slope derivation.

•R Statistical Language, using rgdal, gstat, raster, sp packages:

Reclassifiy slope by those slopes 30 degrees or more.

Polygonize and dissolve.

•PostgreSQL + PostGIS

Storate of resulting slope Shapefile, allows quering slope on intersecting regions.

The process1. Rain gauge observations are collected from MARN web site.2. Rain data is interpolated using ordinary krigin method, the result of thes interpolation is saved as an

image.3. Interpolated rain is reclassified according to certain warning levels.4. The result of the reclassification is intercepted with the slopes previously generated.

The process run every 20 minutes. During extreme rain events this could provide valuable information.

Service visualizationScreenshots taken from the service results with realrain observations

http://104.154.47.186/susceptibilidad/

Screenshots taken from the service results with realrain observations

Screenshots taken from the service results with realrain observations

Screenshots taken from the service results with realrain observations

Rain station reported high value, but was not a valid value

Zooming into the área.

Mobile application Screenshots (Video Demo on https://vimeo.com/137921522)

Mobile application screenshots including estimated rain from spatial interpolation.

What is next? * MARN technical and scientific team will review the result to offer feedback and determine the warning levels and additional inputs to make the visualization valid (They seem to be interested)

* After valitation an update for Weather Hazard can go live, including the developed service.

THANKS

David Eliseo Martínezeliseo.Martinez@gmail.com