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In my studies, I work with the internal dynamics of different snowpatches. In this study I wish to generate 3D models of snow patches. I have some problems when it comes to the actual work flow of creating this 3D model:

Data I have available are GPS points (x, y, and z values​​) over large parts of the research area (these points are collected by using a Real Time Kinematic GPS, on the surface of the snow patches) and GPR (ground penetrating radar) data, which tells me what's under the ground. For example, how deep is the ice, how thick are the snow layers, etc.

My thought is that I want to create a TIN from gps points using height values​​. The problem here is that I do not have GPS points for the whole research area, about 80% is covered.

Question 1: Are there any interpolation tools that can estimate the points where I do not have the point data, based on the points I already have?

When it comes to the actual 3D modeling, that I have a TIN of the glacier, but will now set the GPR data.

Question 2: Would it be best to create eg. three shapefiles one for ice, one for snow and one for firn? Then put different base heights on these files according to the Z value in the GPR data? Or can I do this in a simpler way?

Highly appreciate all the help I can get.

Regards, Jorn

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What software do you have? You tagged 3d-analyst which is a part of ArcGIS. –  nadya Nov 4 '12 at 17:39
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2 Answers 2

To address question one, I highly recommend reading Classification trees of the interpolation methods offered in Geostatistical Analyst from ESRI in order to define your specific interpolation objectives. The interpolation method you choose will be dependent upon the sampling data you collected. In this example, I chose EBK due to its ease of use and improved SE of prediction compared to other Kriging methods. This is a processing intensive operation, so you may wish to experiment with other interpolation methods. Also, consider doing away with the TIN altogether and do a raster-based analysis. If you prefer R, check out the geoR package.

A basic workflow for your purposes would be as follows:

enter image description here

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Thank you very much for the help! Highly appreciate your taking the time to help me with this Will study more about the different interpolation methods, but ran a test now and EBK seems like a good option. When it comes to my question # 2, I will come back with more information about how I see the end result, as well as more information about the data –  Jørn Nov 5 '12 at 10:13
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Answer 1: GRASS GIS has some spatial interpolation function. SAGA also have a couple of them.

Answer2: extract gpx files from GPS device and convert them to 3d shapefiles. (x,y,z) GRASS GIS nVIZ tool is nice 3d viewer. SAGA also has 3d viewer. Apart from this OpenSceneGraph also can read OGR files directly using its OGR plugin. osgEarth will also be a good option. osgEarth is built using OSG. so you can easily visualize any 3d shapefile using osgEarth or OSG itself, but I havent tried it myself.

Hope that helps

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