Blog-O-Tron 5000

Writing Shapefiles

Tim — Sun, 13 Jun 2010 14:01:50 +0000

At work I’m currently working on a fun project called SchetsGIS. Spatial planners are still printing maps and draw on overlays, the idea is to make the lives of the planners and other involved people a little bit easier by using the Microsoft Surface table for this. The project contains some nice features, I will put up a video here later when I’m done with the first version. One of the features is to export the drawings usable within a GIS package for further processing, for now it is only .shp and .kml but probably there will be other extensions added in a later stadium like .mxd and .lyr.

While browsing the internet in search for how to write a shapefile in .Net I only saw some open-source libraries for reading shapefiles but not writing until I came across http://www.easygisdotnet.com/

This is taken from their site:

Easy GIS .NET is a suite of .NET 2.0 GIS and mapping tools and controls to let developers easily incorporate GIS functionality into their applications. Our tools currently support ESRI shapefile format.

If you are looking for a free .NET Shapefile library don’t pay expensive licensing costs for a product that may not give you the same benefits of Easy GIS .NET. Not only is our Desktop version of Easy GIS .NET FREE, you may just find it outperforms expensive commercial software.

Here’s a small snippet how to write a shapefile:
DbfFieldDesc[] fields = new DbfFieldDesc[] { new DbfFieldDesc { FieldName = "ID", FieldType = DbfFieldType.Number, FieldLength = 1, RecordOffset = 0 }, new DbfFieldDesc { FieldName = "TestField", FieldType = DbfFieldType.Character, FieldLength = 255, RecordOffset = 1 } };


            ShapeFileWriter shpWriter = ShapeFileWriter.CreateWriter(shpFilePath, shapeName, ShapeType.Polygon, fields);
            foreach (Feature feature in featureList)

            {

                string[] fieldData = new string[]

                {

                   "0",

                   "test"

                };
                List vertices = new List();
                foreach (System.Windows.Point p in feature.GetPoints())

                {

                    vertices.Add(new PointF((float)p.X, (float)p.Y));

                }

shpWriter.AddRecord(vertices.ToArray(), vertices.Count, fieldData); } shpWriter.Close();

The .shx .dbf and .shp will be created but you have to create a .prj for the shape yourself. I used a normal TextWriter for it:
TextWriter tw = new StreamWriter(shpFilePath + "/" + shapeName + ".prj"); tw.WriteLine("PROJCS[\"RD_New\", GEOGCS[\"GCS_Amersfoort\", DATUM[\"D_Amersfoort\", SPHEROID[\"Bessel_1841\", 6377397.155, 299.1528128]], PRIMEM[\"Greenwich\", 0.0], UNIT[\"Degree\", 0.0174532925199433]], PROJECTION[\"Double_Stereographic\"], PARAMETER[\"False_Easting\", 155000.0], PARAMETER[\"False_Northing\", 463000.0], PARAMETER[\"Central_Meridian\", 5.38763888888889], PARAMETER[\"Scale_Factor\", 0.9999079], PARAMETER[\"Latitude_Of_Origin\", 52.15616055555555], UNIT[\"Meter\", 1.0]]"); tw.Close();

Be aware that a shapefile can only contain 1 geometry type within a Shapefile.

This is perfect for my project and really easy to use.

Here an example of my drawing and the exported shapefile in ArcMap (My drawing created with the Surface Simulator looks awfull but hey you get the idea)

BruTile Silverlight

Tim — Sun, 07 Feb 2010 17:14:38 +0000

BruTile is a open source C# library to access tile services for geodata, with support for WPF, Compact Framework, Microsoft Surface and Silverlight created by my colleague Paul den Dulk.
The last few days I have been working on some extra features for BruTile and a GUI for the Silverlight version.

What I added:
- Possibility to easily create a new layer based on the capabilities of a TMS tilecache, by giving up a url to the capabilities TileSourceTms(“http://t4.edugis.nl/tiles/Nederland 17e eeuw (Blaeu)/”) BruTile creates a layer for the given tilecache.
- GoTo function using the great free service Tiny Geocoder
- Boundingbox zoom.
- GUI for the Silverlight version of BruTile

You can view the BruTile Silverlight demo here

Visualizing GPX Tracks

Tim — Sun, 07 Feb 2010 15:10:31 +0000

For a few days we tracked our daily travelling with the i-gotU device (GPS Logger) After collecting all the tracks in .gpx format Steven created a movie out of it with the help of Processing, an open source programming language and environment for people who want to program images, animation, and interactions. Most of the people who were tracking live around Amsterdam so the cool thing is that you can see Amsterdam slowly showing up.

More information can be found on Steven’s blog and if you are interested in the project you can find the project here

Cyclorama’s on the Surface

Tim — Sun, 07 Feb 2010 14:33:43 +0000

Here a video to show off the possibility to show 360 cyclorama’s controlled with an object on the Surface.

When you zoom in to streetlevel, the Surface contacts the Cyclomedia service and retrieves all cyclorama’s locations within a bounding box and shows the locations on the map. When you put the cyclorama object on the Surface it gets the nearest cyclorama and show it on the 2nd screen. The surface also checks the orientation of the object so that you can look around by rotating the object.

Eagle 1 Surface Demo

Tim — Sat, 27 Jun 2009 11:09:43 +0000

For an upcoming Eagle 1 demonstration in Redmond, WA at the Microsoft Public Safety convention we had to create a Surface demo to show the possibilities of the Microsoft Surface for Eagle 1. Back then we were pretty new to creating apps for the Surface and we had 5 days time with the 2 of us to create something nice. In a meeting we decided the following should be in the demo.

- ESRI WPF control adjusted for touch input
- Showing Symbols and geometries in the ESRI WPF control
- Let an user upload images to a webservice and show an icon on the ESRI control, download and show the photo when pushed
- Get position information from a moving fire engine trough GeoRSS and show the truck on the map
- By placing a tag on the ESRI control, a Virtual Earth 3D view of that place should be shown on an external television
- Showing layers (OSM, VE) in the ESRI control
- Show BruTile on the surface (Open source tiling library created by our colleague Paul)
- Show incomming messages and keep track of all messages in a log
- A Silverlight animation to show the working of Eagle 1
- A document on the Surface where the user can scroll trough
- Place most components in Scatter View Items so the user can arange the controls

In the next few days we created the demo and it turned out that creating applications for the Surface was actually not that hard, offcourse we had some minor problems but I think you always have some minor problems

Here is a video of Eduardo playing with the demo on the 4th day so not all features where implemented yet.

NASA World Wind on the Microsoft Surface

Tim — Wed, 18 Mar 2009 18:58:28 +0000

We’ve been trying to get NASA World Wind to run on the Microsoft Surface, the first problem we ran into was that we didn’t got the current stable version (1.4) to run on the surface so we tried out the 1.4.1 alpha version which worked without any problems. The next thing to do was creating a plugin for Wold Wind which captures all contacts on the Surface, after some searching how to create a plugin we managed to capture the contacts from the World Wind window and added panning, zooming, tilting to certain gestures.

We didn’t had any applications running yet where we used a tag to control something in an application so we decided to create something for the World Wind application. We placed a fiducial underneath a compass and captured the orientation of it and converted the numbers to roll the globe.

The next thing to do is getting all the menu’s to work and give a better feeling to the zooming and panning but that’s for later.