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May 05 2012

Presenting Herbert Run 25 meter grid!

Today Darryl Wise joined me and we went out to finish Herbert Run. It went smoothly and we were able to finish all the points except for one that was under and a car and one that was about a foot under water right in the middle of Herbert Run. What I would like to do now upload the points onto the computer using ArcGIS and this would possibly enable me to view the shots that I have taken in a saved data base. With the points that are in the stream, both 162 and 169 I could come out the day of the tree mapping and provide consultation about where the exact location of the point would be. There are also two off sets to each point, each of which I have recorded. 

Now that Herbert Run is finished I can start on the Knoll, May 11th 2012. The first thing that I will do is create a network of control points. When that is finished I will Start the stake out of the area. I think the Knoll is contained a little more than Herbert Run is therefore it should be topographically easier to survey.

With the use of the data collector and a solid understanding of how the survey will procede I will be able to finish The Knoll magnitudes of time faster than Herbert Run with out a doubt.

One cool thing I want to note about all this surveying that I have been doing is that all these control points that I am using are good control points that could be added to the schools data base of established control. I am not sure if an actual PLS (professional land surveyor) would need to sign of on the authorization of what is "established control" or basically just the legitimacy of the control points.

Apr 25 2012

Finishing up Herbert Run

Saturday April 21st  , Shelby, Dana and I went out to Herbert Run and were able to get a lot done in in the field. We were able to set a decent amount of control points as well as make progress during the stake-out by obtaining roughly 8 more points. The points we were able to get were the ones on the far Eastern edge of Herbert Run 168-175. This leaves us with about 8 or so points left that need to be mapped out and I am convinced that with Dana's help today and a little help Friday that I will be able to complete the Survey either Saturday or Sunday at Herbert Run. Then next week I can do the complete Survey for The Knoll.

This data collector is helping a lot. At Landesign Inc. the data collector I used was no where near as nice as this one is. It can connect to the internet, which could make stake out really convenient. As displayed in the picture on the left the Trimble actually pulls up a complete map of the Survey that I will do. The points you see on the screen are the ones that I have loaded in. It also has my control points which you can see towards the top left of the screen as point numbers 4004 and 4005 These are my traverse 1 and traverse 2. This will be how I establish my traverse loop which because of the small size will probably have quite a small amount of error.

I am considering using existing control at Herbert Run to create control at the Knoll. Since I have specific coordinates for the traverse at Herbert Run I can use those to Run control down to The Knoll. This just means that I will have two traverse loops obviously the one that connects HR to the Knoll is far larger than the one that will be specifically for HR, which entails more error but we can distribute that error evenly throughout the loop and it will be fine.

Finally I am going to need to create the Grid points in GIS this week for The Knoll so that Monday I can get started on that.

Dana also had a great idea when we were out in the field she proposed that we use the GPS to guide us to the points that we are trying to survey. Sometimes these points are in the worst locations such as the points around 170 in Herbert Run and it can be a major hassle trying to read the map and decide what direction and how far is needed to pace to the next point. With the GPS we could get a much better rough estimate of where the next point to be staked out is, for those points that when using the map and actually walking through the forest are impossible to just pace to. This is the situation for large fallen trees in the way, large increases in elevation and streams.

Aug 17 2011

Kinect for ArcGlobe

Yet another reason to get a Kinect - we can get more exercise while using ArcGIS !

According to this blog post- we can use a Kinect to navigate ArcGlobe:

The Applications Prototype Lab atEsri has just completed a prototype using a Kinect to navigate in ArcGlobe.

To fly forward, the user can raise their right hand. The display will navigate in the direct the right hand is pointing. We call this “superman navigation”. If the left hand is elevated, the display will pivot around a central location on the globe surface. And lastly, if both hands are raised, the screen will zoom in or out as the hands are both together or apart.

http://blogs.esri.com/Dev/blogs/apl/archive/2011/08/10/Kinect-for-ArcGlobe.aspx

Shall we get one?

Mar 15 2011

"Simple" Pointcloud Georeferencing

I'm aware that we have multiple transform optimization algorithms of varying completeness in the pipeline, but I decided to try and figure out the simplest means of georeferencing a pointcloud last night.  This is a crude, error-prone method that is only usable when flat ground can be identified.  It performs better when the flat area is large in both X and Y dimensions.  A warning - ArcGIS took tens of seconds to display and classify my pointcloud, and minutes to spatially adjust it.  Shut it down, and you may lose previous work, not just what you're currently doing.  Plan on this taking a while, and multitask.

1. Place readily identifiable markers in your sample area.

2. Take GPS points of those markers using an accurate, WAAS-corrected signal.

3. Take photos.

4. Synth photos.

5. Denoise synth.

6. Convert those GPS points to shapefile format.

7. In Meshlab's Render menu, select the bounding box and labelled axes.  Use the Normals, Curvatures & Orientation -> Transform: Rotate tool in Meshlab with the 'barycenter' option selected to rotate the synth until the flat ground is coplanar with at the X-Y plane.

8. Export the pointcloud as a .ply with non-binary(plaintext) encoding.

9. Rename the .ply to .txt extension.

10. Open the .txt file in Notepad.

11. Replace the header information with space-delimited 'x y z r g b alpha'  and save.

12. Open the .txt file in Excel as a space-delimited spreadsheet.

14. Save as a .csv file.

15. Open the .csv in your planning document in ArcMap, where you already have the GPS points open with UTM coordinate system.

16. Use 'Add XY data' and use the X and Y columns.

17. Right click on the new 'Events' layer and export it as a new shapefile.  Add it to your map.

18. Begin editing that new shapefile.

19. Symbolize the points by color or color ratios using R, G, B columns and cross-reference manually with Meshlab in order to locate your markers.

20. In column alpha (which should have the default value 255), set the marker points to 1.  Symbolize by alpha, unique categories, to make the markers stand out.  Save your edits.

21. Write down the X and Y coordinates of each marker after finding them using 'select by attributes'.

22. Enable the 'Spatial Adjustment' extension, put a check next to the similarity feature, and set adjust data to all features in your pointcloud layer.

23. Place a new displacement link for each marker with the first end at your marker in the pointcloud, and the other end at the corresponding GPS marker in ArcGIS.

24. Hit the 'Adjust' button. 

25. Save your edits and stop editing.

26. Optional: Use SQRT(X^2+Y^2) to determine the distance between two markers in your original coordinate system.  Use the ruler to detemine the distance between them in UTM.  Using the field calculator, multiply the Z factor by the ratio of UTM distance to pointcloud distance.