Digital Geography

Using the Google Earth Engine (GEE) for Detection of Burned Areas

Google Earth Engine ( GEE ) is a cloud platform for processing satellite imageries. This service includes images of Landsat 5, 7,8, Sentinel 1 and Sentinel 2. You can process them directly on Google servers and don’t need download the images. This opportunity does processing of satellite imageries faster then on a limited desktop PC. However, you should have programming skills, because this is based on JavaScript code and the Google Earth Engine API.

planlauf/TERRAIN – a lightweight 3D DEM viewer for daily usage

The visualization and interpolation of 3D terrain (point) data (DEM or DOM) could be a hard task for current GIS software and small to midsize hardware. One thing is the huge possible amount of points and their precision when it comes to airborne or terrestrial LIDAR data with point density < 5m and big areas of interest. Another thing is the rendering performance once the user started his exploration of such a huge dataset. There are several open source and proprietary software solutions and specialized software for several industries. In the following I’ll introduce you to planlauf/TERRAIN, a lightweight DEM…

ALOS World 3D V1.1 vs. SRTM1

Some days ago a new version of the ALOS 30m DEM was released: Void pixels due to clouds and snow pixels within 60 deg. of north and south latitudes in Version 1 were complemented by existing DEMs. Out of the areas are same with Version 1 product. As we already compared ALOS with SRTM-1(I saw the ALOS DEM as “the winner”) I am now interested in how this performs in a another setting. We are changing our focus from Mongolia to Germany and check how the new ALOS DEM works compared with SRTM 1.

Short Announcement: QGIS 3.0 is on its way

QGIS 3.0 is the next big release in terms of features and tools. As it is stated in this e-mail chain we could expect this new major release in late 2017 and time is passing fast: retire 2.14 in June 2017 2.18 becomes LTR from June 2017 to 2018 3.0 feature freeze in July 2017 release 3.0 in Sept 2017 release 3.2 as next LTR in release 3.0 + 4 Months (eta June 2018) Yet this timeline is not strict and [was?] under discussion. We might expect a new candidate loaded with some cool and uncool features.

Map your family tree with Gramps and QGIS – how to digitize and visualize genealogy data

As I realized that I have a really huge family I was keen to digitize the current family tree and get into contact to my relatives. For getting things done, I choose the open source genealogy software Gramps to record all offline information about my family members and create a database as base for further investigations, updates and of course spatial visualization. After that, I exported a database view and visualized it with QGIS.

JuxtaposeJS and the Death (and Re-Birth) of Bogoslof Island

This post is just a quick update on a unique event unfolding in my home state of Alaska and a cool new tool to help you post image sliders on the web.  First, let’s start with the event. The Eruption of Bogoslof Island Over the past few weeks, a volcano has been erupting in Alaska.  This by itself is not that unique, as we have lots of volcanoes and they tend to erupt pretty frequently.  You can check out the current activity for yourself at the Alaska Volcano Observatory.  This most recent eruption is a bit different though.  The island is…

The Atom Code Editor

There is this time of the year when the presents are unboxed and the new year hasn’t started yet, when a lot of people (including me) find some time for tinkering on personal projects. And I guess I am not the only one around here who is working on software projects. But because a proper code editor can make a huge difference,  I want to introduce you to my favorite tool for the job: Atom, a free, open source, modern and extensible, cross platform editor.

Geospatial cloud solutions: Software-as-a-Service vs Roll-your-own

Over the last couple of years, we have seen an increase in demand and offerings of geospatial solutions in the cloud for tasks like web map creation, centralized data storage and management, data vizualization and so on. There is a lot of Software-as-a-service (SaaS) options to explore, but in this article I want to briefly discuss if SaaS is the right thing for you, or wether you should look into rolling your own.

FME and Talend: ETL tools for your spatial data

Spatial data has some formats most of you know (shapefile, geoJSON, TiFF,…). But there is always a wide variety not only in available and used file formats but also in structure of data and formats of the data itself (numbers as text, different separators, etc.). To manage this variety and support the work with a standardized data set most companies use so-called ETL tools to Extract, Transform and Load data. In this article I would like to present you two of them: FME from Safe Software and Talend with Spatial Extension.

Isochrones in Webmaps: Three Approaches for Leaflet

As we are thinking more or less specially I always ask myself: where can I be in the next 30 minutes? Most of current webmaps out there are not answering this quite good using isochrones as example. Most of them taking into account the direct distance which have some major implications if you compare the distance of 30min road trip through the countryside compared with the same time in Paris: about 50km against , right? So I would like to show you, how to get a better idea of reachability using three different approaches but all implemented in Leaflet.

Some ways to produce topographic swath profiles

For a geomorphological study that I am working on I want to produce topographic swath profiles across a mountain range, that is, I want the average elevation along a profile plus the min and max values within a certain distance of said profile. I have used three different methods to achieve that and found some nice resources that I’d like to share with you: GMT – Generic Mapping Tools GMT is a powerful suite of command-line small programs to manipulate all kinds of geographic data (Wessel and Smith, 1998; Wessel et al., 2013). A walk through on how to produce…

Observing deforestation with Sentinel-1

While preparing for an upcoming presentation at the annual meeting of the American Geophysical Union (AGU) I came across a topic that I thought might make an interesting blog post.  The presentation is about using data from the Sentinel-1 mission for Earth Science applications.  The Sentinel-1 spacecraft are C-band SAR systems launched and operated by the European Space Agency (ESA).  An innovative aspect of this mission is that the collection scenario devised by ESA is systematic and very broad in coverage.  Using Sentinel-1 we can monitor Earth using SAR data like never before.

Do you need open data? Ask for it.

The well-known Q/A-forum StackExchange has started a new “Open Data” section. Users can ask for needed datasets and get feedback from the great StackExchange community. Especially for our GIS and webmapping readers this is good news. Often the methodology isn’t the core problem of dealing with scientific or business issues. Often it’s more or less a lack of proper open datasets to run visualization and analyses.

QGIS and basemaps: QuickMapServices

To work in QGIS is very often much more convenient if you can use a basemap for your data. In the past we used and promoted OpenLayers plugin quite often but this was not the best out there as you saw often some issues with projections as well as with “lost tiles” in the map composer. So here is the new weapon of choice: the QuickMapServices plugin for QGIS.