Digital Geography

The End of the Landsat 5 Era

If you have been working in the space remote sensing community for any length of time you have almost certainly crossed paths with Landsat 5. After 29 years of watching Earth, the U.S. Geological Survey announced that Landsat 5 would be retired slowly over the coming months. Of course most people are looking forward to Landsat 8 (LDCM), but it is worth it to look back for a bit on Landsat 5, this stalwart icon of Earth remote sensing. More information from the USGS can be found at the official release As always, thanks for reading.

QGIS Plugins — OpenLayers

Click for previous article in this series about RasterCalc How often have you been working on a project in QGIS and wanted some nice background imagery, perhaps for a quick and dirty evaluation of your own data? I find I need this with growing frequency and a great way to do it is through the OpenLayers plugin for QGIS. Of course, if you know of a good WMS for your area of interest you can always go that route, but the OpenLayers plugin is a great addition to your QGIS toolbox. The OpenLayers plugin is available through the official QGIS…

Kurznotiz: Hilfe zu OpenStreetMap

OpenStreetMap ist ein wunderbares Projekt, dass ähnlich dem Wikipedia-Prinzip arbeitet und eine freie Weltkarte erstellen will. Damit ist das Projekt auch schon ganz gut fortgeschritten. Wer sich über den derzeitigen Stand informieren will, wird hier fündig. Inzwischen hat sich OpenStreetMap auch zu einer unersetzlichen Quelle entwickelt, wenn man günstig Kartographie erstellen möchte, sowohl für Print als auch fürs Web.

How to make a simple topographic map in ArcGIS 9.3.1. Part 1.

So, we all know how a topographical map looks like. On a topographic map, we see different objects, which are indicated by different symbols. For example, we see the elevation marks, vegetation, settlements and so on. But how to make topographic map itself? It is in this article, you will learn how to make a simple topographic map. All we need is a digital elevation model and ArcGIS (I use ArcGIS 9.3.1). Our map will display terrain and elevation marks (contours). As a digital elevation model I will ASTER GDEM v.2. But there are other digital terrain models, such as…

Python for Geospatial Data Analysis (Part IV)

GDAL Geotransforms and World Files The last post in this series considered how to write a geospatially aware file, in that case a Geotiff. In the example the projection and geotransform were read from a file and written into another file with no modification. That worked for the simple example, but isn’t necessarily the most common use case for that type of subroutine. Often you may want to adjust the data based on your analysis. Most geospatial professionals are probably familiar with world files, or have at least run across them. They are a good way to georeference data that…

FastGAPP – Fast Geochemical Analysis Plotting Program

Geochemical studies of igneous rocks are fundamental to classify rock types in terms of main-, minor-, trace element whole-rock chemistry. Together with petrographic observations from thin sections it is possible to classify igneous rocks and to draw interpretations about: The petrogenesis and evolution of igneous rocks. The thermal and barometric conditions in which a primary magma have formed. The magmatic processes that might be involved in the evolution of igneous rocks. The geotectonic environment in which igneous rocks might have formed. Specific programs for the evaluation of geochemical data of igneous rocks are rare and often very difficult to use.…

Favorite QGIS Plugins – RasterCalc

RasterCalc QGIS Plug-in QGIS is an open-source geographic information system that is familiar to many geospatial professionals. I find more and more that I’m able to use QGIS for most of my GIS needs and this is in large part due to the great plug-ins that are available. In this post I want to give an overview of one of my favorite plug-ins, RasterCalc. If you have QGIS installed on your system, you can download RasterCalc from the official plug-in repository, here. After downloading, you can install it in the appropriate location for your system. In my case that is:…

Python for Geospatial Data Analysis (Part III)

Writing Geospatial Files In the last post in this thread I began discussing basic syntax and how to open and read a geospatial raster file. This installment in the series will demonstrate how to take the data we read from the file and write it out to a new file. In this case, we won’t change anything in the data, just use it as a means to demonstrate writing a file. In order to write a file, there needs to be a small addition to the subroutine for reading data. In the previous post the subroutine didn’t return the data…