Digital Geography

Google Earth Engine – free spatial data- and analyse-workspace

Google’s Earth Engine offers spatial researcher-tools in combination with their huge amount of collected satellite data. In fact you have the possibility to access e.g. 40 years of LANDSAT-data (of course for free) and show it in your browser-worspace. But this is just the beginning. Explore detection of deforestation, landcover classification, biomass and carbon estimates and much more.

Rainfall and weather data on GoogleEarth

On Saturday, some villages near my hometown suffered heavy rains. Up to 100 l/m² arrived during the afternoon and evening in Kirchhasel and other places in central Thuringia. Small streams became rivers and flash flooding occurred, damaging houses, roads, and cars. The local newspaper has an impressive pic dump. Locals say this have been the worst flooding for at least 40 years, so pretty much excitement here, we are not really used to this despite the river Saale caused some heavy floodings in the past. Now it looks like thunderstorms will arrive again: So I had a reason to think…

How to find geospatial data for Spain

In some countries, such as the USA and Spain, there is a very nice law that makes life easy for geoscientists. This law guarantees free access to a broad range of geospatial data like DEMs, satellite imagery, aerial photographs, ground use data, hydrological information and so on. In most cases, these data are made public via web-based GIS applications. These are generally rather slow, but allow to display a lot of different datasets. I did both my diploma thesis and my PhD in Spain and I really needed to find out about all the data available. I knew that they…

short announce: Reverb @NASA the new WIST

Sorry to talk about this important tool with a little delay. As I was lecturing at the university I was using the Warehouse Inventory Search Tool (WIST) by NASA to collect my raster data and download them. It was a great tool but looked a little old. The biggest difference to services like landcover.org or the SRTM Tile Grabber is, that most data was ordered and delivered by FTP. It was not a big deal as most data was available for free but I think for a lot of users this was not “convenient” enough… Nevertheless Reverb- the new WIST-…

Free Data and Maps from the European Environment Agency (EEA)

Behind this heading a real highlight is waiting. The European Environment Agency offers a massive amount of interesting datasets touching different themes of europe and the world. Additional to infographics, charts and much more, you can find interactive material about the latest environmental developements in europe. Nearly all datasets are free available.

Map Projections, spatialreference.org and gdalwarp

Map Projections The question of map projections and how to reproject data is one that comes up often in discussions with both experienced colleagues and those new to the geospatial profession. I’m not going to go through a complete discussion of map projections here, as there are many resources available on the Internet that can help you. I’m going to focus more on how to move data between projections. At its most simple a map projection is simply a mathematical description of how to take data on the surface of a sphere, that are inherently 3-dimensional, and transform them to…

Possible application for topologies

Most of my students asked me: “why do we need this or that!?”. In fact: for topologies I failed in answering often. One possibility of usage is shown here: In fact I was confronted with this problem more then once: two neighbouring polygons, move one, move the other and hope that snapping will do the rest. Using the topology tools in ArcGIS makes this much easier as it treats your shared vertexes as one vertex and adjust the geometry of both polygons… “Thumbs Up!” for that! Find more informations on topology here: LINK