Tag: QGIS

Other, QGIS

Latitude and Longitude of projected points in QGIS

Often one has points in QGIS in a given coordinate system and wants them in latitude and longitude for various reasons. Solutions I have used in the past included converting to WGS84 EPSG:4326 and then using the field calculator in QGIS to calculate X and Y values for Longitude and Latitude respective, exporting to CSV while projecting to 4326, or pulling into PostGIS and writing … Continue reading Latitude and Longitude of projected points in QGIS

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Cartography, QGIS, TileStache

QGIS Compositing, more gushing yet…

Ever had a workflow on the web that resulted in stuff so nice, you wanted to replicate on the desktop?  Ya, me neither until recently.  I love the cartography a particular website, know all the bits and pieces of color and effects that go into, but had no desktop application that could do the same.   Until now.  On the left, QGIS, on the right, TileStache … Continue reading QGIS Compositing, more gushing yet…

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Cartography, QGIS

Quantum GIS Compositing Continued

QGIS compositing is not limited just to between layers, but also for elements in the Print Composer. How is this useful? Every want a non-rectangular map? With 1.9 alpha, you can use an SVG to affect the elements under it.  On the right, the svg.  On the left, the map element inside the Print Composer. Overlay the two with “Blending Mode” set to “Normal” and … Continue reading Quantum GIS Compositing Continued

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Analysis, Optics, Other, POV-Ray, QGIS

Way beyond red-dot fever– bees hives and overlapping home ranges

Last week, post Boston Code Sprint, I spent a couple of hours playing with bee data, specifically bee keeper data for Norfolk County Massachusetts. My friend Eric (a bee keeper of 4 hives in said county) says that worker bees can fly as far as 3 miles for nectar, but after that approximate limit, they hit diminishing returns relative to the calories they burn. Proximity … Continue reading Way beyond red-dot fever– bees hives and overlapping home ranges

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QGIS

Cartographic tricks and tips– making text readable.

I was playing recently with techniques for making text/labels in maps more readable in a map.  We can use simple buffers to do this, but this isn’t always adequate.  Take this example: which is a label on top of contours.  It is adequately readable.  If we show 2 ft contours as well, the map becomes somewhat cluttered: So, we apply the common technique of halo … Continue reading Cartographic tricks and tips– making text readable.

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