Google Earth, Google SketchUp and GIS Software; An Interoperable Workflow for Generating Elevation Data

Abstract

Data creation is often the only way for researchers to produce basic geospatial information for studies concerning river basins, slope morphodynamics, applied geomorphology and geology, urban and territorial planning, among others. This exercise results from an idea initially presented to students in a class context at the Geoinformatics Lab (Geography Department - University of Coimbra, Portugal). The main hypothesis (and goal) of this methodological essay was centered on the idea that it could be possible to develop an interoperable workflow where specific data processing tasks executed in Google SketchUp could produce elevation data that could be exported and geoprocessed with open source Geographical Information Systems (GFOSS) software. It starts with Google SketchUp (GS) graphical interface, with the selection of a satellite image referring to the study area – which can be anywhere on Earth's surface; subsequent processing steps lead to the production of elevation data at the selected scale and equidistance. This new data must be exported to GIS software in vector formats such as Autodesk Design Web format – DWG or Autodesk Drawing Exchange format – DXF. In this essay the option for the use of GIS Open Source Software (gvSIG and QGIS) was made. Correcting the original SHP by removing "data noise" that resulted from DXF file conversion permits the author to create new clean vector data in SHP format and, at a later stage, generate DEM data. This means that new elevation data becomes available, using simple but intuitive and interoperable procedures and techniques which configures a costless workflow.