Digital Geography

Landsat in Love with QGIS: the newest coup from Luca

The normal way of getting Landsat data for your GIS projects often was: visit a Landsat data mart like landcover.org, earthexplorer or WIST, search for your area and time and download/order your desired data. Once you’ve done this, you were prepared to add, analyse and publish this data/results with QGIS. Luca Congedo from the blog “From GIS to Remote Sensing” .

Geocoding Addresses in ArcGIS: the other approach

Today I stumbled upon a post from the German ESRI office and their blog gisIQ and a little tutorial (English translation) on how to geocode addresses in the ArcGIS platform. I was asking, whether there is a possibility to use other geocoders as well and so I tried to build my own solution without credits and with the possibility to choose a geocoder. Fortunately the Python world offers some nice little scripts. So let’s use geopy!

Short Announcement: QGIS 2.8 Wien released

QGIS 2.8 (the new “Long Term Release”) was released a few days ago. It is a minor release according to the changelog but it will be supported in this setup at least for the next year: Some good news for all those working in a bigger, administrated environment as it is always a problem to update software in these bigger infrastructures. New features: >1000 issues flagged by static analysis tools fixed new code commits and pull requests are now automatically tests against our testing framework. more responsive browser support for contextual WMS legend graphics custom prefixes for joins creation of…

Creating ARCs in QGIS: The Python Way

So I came across this nice little project which focussed on trip planning and route over large distances… And there was this nice little post from Nathan Yau at flowingdata.com where he describes the making of great circles from one point to different other points in R and the other example from Anita Graser where she shows how to deal with an Arc in QGIS but using postgis functionality. So what about QGIS itself and a programmatic way? See yourself…

Attribute Updating using ArcPy

After my first attempt in Python scripting using opensource Geospatial Data Abstraction Library (GDAL), I wanted to use ArcPy  in my second trial. The following code is so simple. You can use it to update the attribute table of a shapefile based on another shapefile/table. Let me break it down using this pseudo-code: Choose the first shapefile (the source). Identify the unique ID field in that shapefile. Write down all the values from the desired field (to replace the old values). Choose the second shapefile (the destination). Search for the unique ID records which meet that unique ID field in (step 2). Update…

QGIS 2.8: A Preview

QGIS 2.6 landed recently on this planet and it already brought great improvements to our daily work with geodata, the way we publish our results and the convenience in our workflows. But due to the very ambitious release plan of the QGIS core team and the great work of Klas we can have a look at the upcoming features in QGIS 2.8 major version already. Check em out:

A small tool with Python: the shapefile archiver

Let me introduce to you, guys, my first Python tool: “Shapefile Archiver”. Usually, I face lots of problems in managing my shapefiles. My first problem is backing them up in a decent way, especially, before starting some experimental things on them (That sounds scary!), while the second problem is that Finder/Windows explorer doesn’t tell me about the shapefile more than its name!. Moreover, Finder/Windows explorer shows the shapefile as a bunch of files (*.shp, *.prj, *.shx, *.dbf,…) which makes me feel annoyed especially because I’m too lazy to open QGIS browser or ArcCataloge every time I want to explore my…

Create custom markers with R for your webmap

When it comes to webmapping there are thousands of possible markers you can choose from but when it comes to markers depending on the data, which is inside the shapefile, possibilities are more limited. In leaflet you can define different icons according to the attributes of your data by defining the icon url in an attribute. Let me show you, how to use the data in each feature to create a custom icon like a piechart marker using R.

SciPy integration in ArcGIS

Most of GIS users today will probably work with ArcGIS. Since version 10 the implementation / integration of Python into the ArcGIS framework and ArcPy it’s important for ArcGIS users to be aware of the capabilities of using Python in batch processing tasks, data manipulation and the broad possibilities of Python itself (eg. Numpy, Sympy etc.). SciPy will another topic for the future…

Non-standard use of Web GIS on the example of OpenWebGIS functionality

In this article we consider the use OpenWebGIS, as one of the free Web GISs for analyzing of buildings drawings, as well as mapping and measurement of small-scale objects that are demanded in archeology, architecture, biology, medicine and other fields of human activity. Tell me, how many online Web GISs can use the maximum zooming ratio of more than 19? Those Web GISs which use OpenStreetMap as a base map, generally have a maximum zoom to 19. Those Web GISs which use Google Maps as a base map, can increase to no more than 19-20, but in some cases this…