Mom who Maps

While I have been so problematic before how to resample my billions of points to have it visualized in 3D and further perform analysis over it, I found out that ArcGIS would be the best solution. The usual discretization is performed on my data, I scraped out all the noisy points by limiting my range to 5cm o 100m. Now I added another criterion, that is to remove all points below my LIDAR setup. That is to consider theta(horizontal FOV)<90 and theta >270 degrees. That in a way reduced my point cloud into almost 30% of the original. Memory-wise, it was a LUXURY already! Now for checking the irregularities in the observed point cloud, using the Point File Information Tool is by far the best solution. Using ArcGIS 10.0: 1. Go to 3D analayst tools>Conversion>From File> Point File Information. 2. You will be opt to browse lidar point cloud by File or by Folder. (I suggest that you browse by Folder if you've got more than 10 files.) 3. Now you will be opt for the f...

I had some problems using my previous Matlab script on generating the converted latitude, longitude and height from the ECEF -X,Y,Z coordinates. for k = 1:5     matFilename = sprintf('%d.csv', k);     M = ecef2lla(textread(matFilename));     dlmwrite('sample.xyz',M, '-append'); end What happens right here is that it writes formatted values of the latitude, longitude and height formatted in three columsn but in 5 significant digits only hence creating duplicated coordinates which scraped up most of my values in the sample.xyz. It took me the whole long weekend to figure out how to improve the results, I know it's on the formatting only and  not on the predefined classes per se.  As I've always been familiar with the %3.2f tag for specifying the decimal places in a float, I have been trying all the way to fit in my argument but to no avail. I'm almost giving up on using the "dlmwrite" function and tried using the "fprintf...

I have always used ArcScene for visualizing my GIS data in 3D. However, some issues may arise if your data, specifically DEM is in geographic coordinate system (latitude, longitude). You just have to do some minor settings to make things work really... Here's my fare share on viewing your DEM in 3D using ArcGIS ArcScene. (For this post I used ArcGIS 10.0, I have also tried it working in ArcGIS 9.3). Here's it. Enjoy your mapping and geovisualization everyone! :)

If you have a DEM, you might want to view it in 3D. For me, I do geovisualization in ArcScene, VTP or for simple presentations I use Google Earth. DEM or digital elevation models contain the heights of our terrain. It has a commonly interchanged counterpart term known as DTM (digital terrain model). DEM differs from DTM in the sense that DEM is not the elevation from the ground per se. It is the height with the buildings and other cultural features. DTM on the other hand gives the height of the bare ground. For DEM, we can obtain freely available datasets such as SRTM and ASTER . SRTM resolution is 90m X 90m for the Philippines while ASTER is 30m x 30m. Though ASTER is of higher ground sampling distance than SRTM, researches show that SRTM still proves to be more accurate than ASTER.  So for the purpose of visualizing our terrain in 3d. What we would first want to do is to prepare the DEM (i.e. SRTM DEM ) for processing. If we fail to do this, we will be confronted with a very...