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Archive for 'GIS'

Create World Files For a Directory of KMZ/KML Raster Files

A while back, I worked on a project that required the conversion of a number of KML/KMZ (Google Earth) raster files into vector format (don’t ask!) Because there were a lot of files, it was painstaking to manually geo-reference the files after unzipping the KMZ to extract the raster files. I dug around on the […]

Dissolve Shapefiles using OGR

Quite often, I’ll run across a large or complex shapefile that causes issues (crashing, very poor performance, etc) in QGIS or other desktop GIS. However, sometimes you have to find a way to deal with these files, and not spend a lot of time worrying about them. Often, the best way is to head back […]

Label Only Features Intersecting with Current Atlas Feature in QGIS

If you’ve ever used the excellent Atlas functionality feature in QGIS, you know that you can make some very nice map books (‘atlases’ in QGIS parlance) with feature-driven layouts, titles, styling, etc.. This functionality is becoming more and more advanced in recent releases. Yesterday, I was working on an atlas, and wanted to label only […]

Create Midpoints Along Lines with OGR

Today I found myself trying to create a ‘midpoint’ on a large shapefile line layer. QGIS doesn’t have a tool to do this, and because the layer was large, I really didn’t want to mess around converting file formats to stick it into a database. However, similar to my last post about Creating Points On […]

Creating Points On a Surface using OGR

If you’ve ever had to create a point on a polygon surface, you fairly quickly realize that there’s a lack of easy tools that will perform this task. Almost every desktop GIS package will create a ‘centroid,’ but that doesn’t work when you need to find a point that’s guaranteed to fall on the surface […]