Admin at 00:20, 17 April 2017

2017-04-17T00:20:56Z

← Older revision		Revision as of 00:20, 17 April 2017
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	done making 3D planes		done making 3D planes
	</pre>		</pre>


			[[Category:Shapefiles]]
			[[Category:STL]]
			[[Category:Shapes]]
			[[Category:GIS]]
			[[Category:Javascript]]
			[[Category:Node.js]]

Admin at 00:20, 17 April 2017

2017-04-17T00:20:30Z

← Older revision		Revision as of 00:20, 17 April 2017
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			Shapefiles (.shx, .shp, and .dbf bundle of files) are a data format for storing geospatial vector data. Shapefiles can describe vector features like points, lines, and polygons, and can add extra attributes to shapes.

			The shapefile format stores ''everything'' as a vector feature, i.e., as a set of points. This means that any curvature is discretely represented, and resolution therefore relies on scale. (Compare this to other formats that use things like splines to maintain smooth curvature at arbitrary scales).

	==Converting Shapefiles to STL Files==		==Converting Shapefiles to STL Files==

Admin: Created page with "==Converting Shapefiles to STL Files== Typically, GIS information comes as shapefiles, which are readable by GIS programs and libraries. However, if we want to do non-GIS-spe..."

2017-04-17T00:16:37Z

Created page with "==Converting Shapefiles to STL Files== Typically, GIS information comes as shapefiles, which are readable by GIS programs and libraries. However, if we want to do non-GIS-spe..."

New page

==Converting Shapefiles to STL Files==

Typically, GIS information comes as shapefiles, which are readable by GIS programs and libraries. However, if we want to do non-GIS-specific tasks with GIS information (like [[3D Printing]]), we need to convert the Shapefile (GIS-specific) to an STL file (readable by CAD software).

I downloaded contour elevation data for the Seattle area, which was contained in a zip file called <code>Elev_322166_Seattle_E_1X1.zip</code>.

Unzipping results in a pile of files of various formats:

[[Image:NationalMapViewerFiles.png|200px]]

The one I'll use there is the shapefile.

We'll use the shp2stl utility to convert the shapefile (GIS format) into an STL file (3D printing format).

Nice writeup/utility here: http://dougmccune.com/blog/2014/12/30/using-shp2stl-to-convert-maps-to-3d-models/

Download Node, and get npm. Use npm to install shp2stl utility:

<pre>
$ npm update
$ npm install shp2stl
</pre>

Here is the javascript file that I used to convert this shapefile to a stl file:

<pre>
$ cat stlify.js
var fs = require('fs');
var shp2stl = require('shp2stl');
var file = 'Elev_Contour.shp';
shp2stl.shp2stl(file,
{
width: 100, //in STL arbitrary units, but typically 3D printers use mm
height: 10,
extraBaseHeight: 0,
extrudeBy: "Pop_psmi",
simplification: .8,
binary: true,
cutoutHoles: false,
verbose: true,
extrusionMode: 'straight'
},
function(err, stl) {
fs.writeFileSync('SeattleContours.stl', stl);
}
);
</pre>

To run this, just pass it to node:

<pre>
$ node stlify.js
bounds: Infinity Infinity -Infinity -Infinity (spherical)
pre-quantization: 111.195km (1.00°) 111.195km (1.00°)
topology: 0 arcs, 0 points
topojson done
simplification: effective minimum area 0.00
simplification: retained 0 / 0 points (NaN%)
making top planes
making side planes
making bottom planes
done making 3D planes
</pre>

Shapefiles - Revision history

Admin at 00:20, 17 April 2017

Admin at 00:20, 17 April 2017

Admin: Created page with "==Converting Shapefiles to STL Files== Typically, GIS information comes as shapefiles, which are readable by GIS programs and libraries. However, if we want to do non-GIS-spe..."