I am trying to render a local elevation data on World Wind. And then use the world wind's tessellation algorithm to tessellate the data and render it on the globe.
I know about the LocalElevationModel. and I was able to store a DEM file using this:
LocalElevationModel localElevationModel = new LocalElevationModel();
String filepath = "";
localElevationModel.addElevations(filepath);
I can access this model using the lookupElevation method over the max,min lat log from the localElevation data. But I don't know how to proceed forward. I have looked into the RectangularTessellator class but couldn't understand how to use it.
Any clues on how I can do this?
PS:I was looking at their source code but couldn't understand much to make much scene out of it. So I wanted to know more about it.
PPS: If not possible can someone guide me to an easy to implement and optimized algorithm for rendering of the terrain. Which supports various LODs of the generated mess.
Thanks,
Related
Trying to convert a .csv file which is a point cloud plot but in a sequential type plot..it has all three coordinates and a date time stamp/point..
What I’m trying to do is connect the dots and create a spline for other objects to attach…
Any help would be appreciated..
Was trying to follow the python script on another sub chat..
Fit Curve-Spline to 3D Point Cloud
Was trying this in cinema4D but it doesn’t seemingly handle this level of work..this might be for python patch in blender…
But also mathlab or maple would be a good alternative if anyone out there can help, let me know…
I'd like to hear your thoughts on what would it take to make cubism work with non timeseries data, concretely, genomic data.
These type of data has a locus (a chromosome and coordinates within that chromosome) instead of a timestamp:
chrm1 145678123 value
chrm12 45345 value
chrmX 4535 value
....
What option do you think is best, hacking cubism's core to allow for these type of data (or any type of data for that matter) or spawning a new project all together?
UPDATE: I decided to implement a modified version of cubism for DNA. I call it DNAism and you can find it here. Take a look and let me know what you think.
-drd
Cubism is probably not the right kind of library for this task. You're going to have to modify the library in a pretty significant way. Instead of doing that I'd recommend you use the d3.horizon plugin so that you can gain a lot more control by creating custom scales.
Hope this answers your question.
Is there a way to understand what an image is about? I mean, if I scann a picture, how can I tell that the picture is about a spesific object? I am thinking that if I have some shape in mind, say the shape - pattern of a spesific object that meets its requirements against the object I am searhcing for, then it must be what I am looking for. Anyway I am thinking of an algorithm to scann a picture database and figure out the pictures I am actually looking for,Is there a known way to accomplish such operation?.
If I am reading your question correctly...
This is a very daunting task even for full-fledged corporations like Google, though they are attempting to create something along these lines.
Take a look at Google Goggles for Android if you'd like to see how this sort of system behaves. You'll also notice that it requires very specific circumstances to be even slightly reliable, but the base technology is there.
I am new on this, and my objection is to build some web application that implement the user to store an image on a database as a storage, and all I want is to reduce if there is a couple or some image that stored twice or more.
So, all I need is how to find duplicate or similar images that already stored on a database, or even better when the user try to import it on the first step, and if their image are similar with an images that already been stored on a database, the system can gave a warn not to store that image.
I just want to develop how to find some similar or duplicate image on a specific directory on a database. Can you give me some explanation from the first about how to build it, and what should I learn to accomplished this from the basic step, like a tutorial or something. I'd like to learn a lot, if it's possible.
Thanks in advance, I really need this help, thanks.
The solution for finding similar images is much more complex so I will stick to the finding duplicate images first. The easiest thing to do is to take a SHA1 hash of image bits. Here is some code in C# to accomplish this (see below). As for storing the hash in a database, I would recommend that you use a binary(20) datatype to store the results of the hash. This allows your SQL server to index and query much faster than storing this hash as a string or some other format.
private static byte[] GetHashCodeForFile(string file)
{
int maxNumberOfBytesToUse = 3840000;
using (Stream sr = File.OpenRead(file))
{
byte[] buffer = (sr.Length > maxNumberOfBytesToUse) ? new byte[maxNumberOfBytesToUse]: new byte[sr.Length];
int bytesToReadIn = (sr.Length < maxNumberOfBytesToUse) ? (int)sr.Length : maxNumberOfBytesToUse;
sr.Read(buffer, 0, bytesToReadIn);
System.Security.Cryptography.HashAlgorithm hasher = System.Security.Cryptography.SHA1.Create();
byte[] hashCode = hasher.ComputeHash(buffer);
return hashCode;
}
}
Searching for similar images is a difficult problem currently undergoing much research. And it kind of depends on how you define similar. Some prominent methods for finding similar images are:
Check the metadata (EXIF or similar) tags in the image file for creation date, similar images can be taken at times that are similar to each other. This may not be the best thing for what you want.
Calculate the relative historgram of both images and compare them for deltas in each color channel. This has the benefit of allowing an SQL query to be written and is invariant to image size. An image that has been converted to a thumbnail will be found with this method.
Performing an image subtraction between two images and seeing how close the image gets to pure black (all zeros). I don't know of a method to do this with a TSQL query and this code can get tricky with images that need to be resized.
Calculating the contours of the image (through Sobel, canny or other edge detectors) then subtract the two images to see how many of their contours overlap. Again I don't think this can be handled in SQL.
Presently I am having problems obtaining elevation point data from the SRTM3 format (.hgt) from NASA. I wish to use the data for creating a program that creates a 2d panoramic illustration of the given area based on the elevation points extracted.
I've exhausted a lot of resources from the Net but still to no avail.
What I want to ask is a form of pseudocode for me to be able to read .hgt files and obtain data from them so I can feed something to my program.
Thanks a lot!
You Could use UniboGeoTools a very small java library that provides Elevation Info in two way: SRTM and Google Elevation Api.
Take a look at the test to understand how it works ..
a pseudocode is:
file a = '~/S41W072.hgt'
size = 1201*1201
for(int i=0;i<size;i++){
int bb= a.readByte();
printScreen(bb,i%1201,(1201-(int)(-1+i/1201)));
}
I have java code somewhere, if I find it I'll upload