Tag Archives: GIS

Coordinate Reference System Transformations in Javascript

Yes, you can do coordinate reference system transformations in Javascript. (I know, I’m shocked also.) I found proj4js on GitHub, which is a port of an older project, PROJ.4. The proj4js library is very easy to use. All you need to do is find the specification strings at spatialrerefence.org of the two projections/datums you are interested in and you’re ready to go.

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Adding Data Points to Shapefiles

In this post I’ll discuss how to plot data points on a shapefile. In a previous post I discussed how to install basemap using pip, the package manager for Python. Since basemap is an extension of matplotlib, we have a lot of familiar plotting functions and options at our disposal. Of particular importance is the ability to use projection data in plotting the shapefile, and plotting the data points.

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Using QGIS and OSGeo4W for Geo-Data Tasks

In this post I’ll discuss creating and altering shapefiles, and converting point sets from one coordinate reference system to another. I’ll also touch on scripting these tasks for large data sets. I’ll begin with the installation of Quantum GIS and Python for manipulating geographical data. I mainly use QGIS for visualizing and building shapefiles, and I use OSGeo4W from the command line for adding/converting shapefile projections, and converting point sets from one CRS to another.

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