I have .las (lidar data) file, now I wanted to know the size of it, for example how long it's width and height in kilometers.
How is it possible to retrieve these kind of info?
tl;dr: install libLAS and run lasinfo myfile.las.
Lasfile headers, in general, shouldn't be trusted since they may not agree with the true data bounds. A more robust approach is to calculate the spatial extents of the data by reading the points themselves. Here's a few free and open-source ways to calculate the true bounds of a lasfile:
libLAS, via lasinfo mylasfile.las
libLAS can also be compiled with LASzip support to read .laz files
PDAL, via pdal info myfile.las
PDAL can also be configured to read other types of pointcloud files, including compressed .laz and more
If you want to inspect the lasfile's extents (and other properties) programically with Python, you can use laspy
Many of these software projects are available via package managers for your system:
Windows: OSGeo4W includes libLAS, LASzip, and PDAL
Ubuntu: sudo apt-get install liblas-bin will install lasinfo on Ubuntu 14.04, 12.04, and others
OSX: brew install pdal liblas using Homebrew
laspy can be installed via pip install laspy
You best bet is to use a specific software to find out the extent of this lidar file.
Another way you can probably do it is to look at the header section of the file (if you have the raw file), which must state the extent as well.
Otherwise, talk to the data provider (if you can´t find out the extent any other way). He probably has the software and knows the extension of your dataset.
George
You can use the lasinfo utility from lastools which will return the .las header information (including the extent):
http://www.cs.unc.edu/~isenburg/lastools/
The lasinfo module in SAGA GIS will provide the same information:
http://www.saga-gis.org/
With Fusion, an option is the command line Catalog to retrieve descriptive statistics.
Suppose Fusion is installed under the directory c:\fusionand the las file is stored in c:\lidar\point_cloud.las. Write and run:
c:\fusion\catalog c:\lidar\point_cloud.las c:\lidar\point_cloud
An output example is:
Add switches to obtain more information or to adapt the command to specific needs (e.g.; switch 'coverage' will show nominal coverage area of the entire lidar cloud).
Related
Hello guys sorry I am new to docker so bear with me.
I am learning to use docker for building, running and shipping some apps but still don't know the difference between Node images (ex. latest, alpine..)
I've read somewhere that alpine is a small Linux distribution (in terms of size) but still don't know the difference between all these images and especially when to use which?
Dockerfile:
Usually there is a description of the different types of images available within their docker hub page.
For Node we have it here: https://hub.docker.com/_/node
The section Image Variants states the following:
node:<version>
This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.
Some of these tags may have names like bullseye, buster, or stretch in them. These are the suite code names for releases of Debian and indicate which release the image is based on. If your image needs to install any additional packages beyond what comes with the image, you'll likely want to specify one of these explicitly to minimize breakage when there are new releases of Debian.
This tag is based off of buildpack-deps. buildpack-deps is designed for the average user of Docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.
node:<version>-alpine
This image is based on the popular Alpine Linux project, available in the alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.
This variant is useful when final image size being as small as possible is your primary concern. The main caveat to note is that it does use musl libc instead of glibc and friends, so software will often run into issues depending on the depth of their libc requirements/assumptions. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.
To minimize image size, it's uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).
node:<version>-slim
This image does not contain the common packages contained in the default tag and only contains the minimal packages needed to run node. Unless you are working in an environment where only the node image will be deployed and you have space constraints, we highly recommend using the default image of this repository.
All of the standard Docker Hub images have a corresponding Docker Hub page; for Node it's https://hub.docker.com/_/node. There's a section entitled "Image Variants" on that page that lists out the major options.
Debian/Ubuntu/Alpine. Most Docker images are built on top of one of these base Linux distributions. Debian and Ubuntu are very similar and in fact are closely related; if you see something labeled "bullseye", "buster", or "stretch", these are the names of specific Debian major releases. Alpine has a reputation for being very small, but with that tininess comes some potential low-level C library issues. I'd recommend the Debian-based option unless you really need the tens of megabytes of space savings.
"Slim" images. The node image has a "slim" variant. The default image mentions that it's built on top of a buildpack-deps image, but that base image is not small (~300 MB). That image includes a full C toolchain and many development headers. Some npm install commands could need this, but you don't want it in your final image. Prefer the "slim" option if it's a choice.
Version tags. The top of the Docker Hub page has a bewildering list of tags. If you look at these, each line has several names; as of this writing, node:16, node:16.14, node:16.14.0, node:lts, node:16-buster, and several other things are all actually the same image. One thing to note is that only "current" versions get any sort of updates at all; if Node 16.14.0 is the current version then no node:16.13 package will ever be rebuilt. I'd suggest picking a specific major version and using a "long-term support" version if it's an option, but not specifying a minor or patch version.
Combining all of those together, my default would be something like
FROM node:16-slim # Debian-based
I wanted to install the OV7251 camera driver to work with a module I've recently purchased, the Arducam OV7251 MIPI, as I need to perform SLAM-like system called Virtual Inertial Navigation (VIN) and global shutter cameras are preferred for this. As far as my system goes, I'm using ROS Kinetic on an RPI-3B+ running Ubuntu 16.04 . I am using this camera as it is near my price point (<20$), and goes through the RPI's CSI Port, which sources say is easier and faster than ones going through USB.
I wanted to take this camera and publish its data to a topic, that way the repository I'm using for VIN, OpenVINS, can track the camera's position. Now, the camera that I'm using doesn't have much on it other than the manufacturer's github page, which does not work on Ubuntu, and cannot connect to ROS. Now, I'm decently inexperienced with RPI's, ROS included, since I wanted to originally perform this on an Arduino, but that was majorly impossible, so I doubt I would be able to write a simple ROS node, let alone one that connected with the CSI port.
Currently, I am unable to find many libraries for this, and help given to me has proved to be un-substantial. The camera does not natively have drivers supported on RPI, which is why I cannot find any /dev/video libraries, cheese turns up nothing, and the command $ Vcgencmd get_camera returns no detected devices. Someone suggested kernel hacking, in order to enable the module in menuconfig using libraries like the ones here. While I do not know much about kernel hacking, he reccomended that I follow this guide and after I run the defconfig line, I should search for "OV7251" in menuconfig and modularize the only one which popped up. And despite flashing and repeating this process multiple times to ensure I did not choose the wrong branch, the rpi-5.4.y branch, or wrong model, the RPI-3B+, I ended up being stuck on the rainbow screen after I rebooted every time. I know that the rainbow screen either means low power, which it wasn't because I had it run before, or a kernel error, which would most likely make sense.
Now, while I would most definitely like to fix the rainbow screen error, I would also like to know, how after installing the OV7251 driver, how do I get it working with ROS to send data to topics? Since I doubt I could write my own node, is there a library that I could look for to perform this, or would libraries that did not work previously due to a missing driver suddenly work now, or would I have to take an existing one and modify it? In any case, A more low-level tutorial to accomplish this would be quite handy seeing as I am new.
But, in the case this is not software, and the reason this camera is not supported is for good reason, is there any other cheap global shutter camera I can work with? I couldn't seem to find many over my various searches, but maybe you all have better luck/experience in this field. Although, I did manage to find another library by this same manufacturer which happens to support my camera model and even has a ROS node that works on ubuntu. However, I believe that if this can be done, then so can doing so by just the CSI port rather than buying an additional 40$ USB camera hat for the pi, and along with that, I am starting to doubt the validity of this companies repositories.
Yet the fact I am finding little information on the topic of this camera alone on the CSI port of an RPI and how renowned this company it scares me that it could be impossible, which if it is, do link me some other good and hopefully well-documented cameras, which could very well be a lot to ask for. And if it is just simply impossible to get the results I want with the parameters I have set, then how badly would a rolling shutter camera affect VIN'S performance, and furthermore is there any special dataset designed for rolling shutter which could minimize the drop in quality? This terrain is all too new to me.
Ok, so I got a rpi engineer to add a dtoverlay for the ov7251 in the rpi's firmware, and the most recent rpi-update has the overlay in the kernel.
I did sudo rpi-update to install the update, i then added dtoverlay=ov7251 to /boot/config.txt in order to enable the overlay, and i edited it by running sudo nano /boot/config.txt. And the repository only has one dependency, v4l-utils, which is installed easily enough by running sudo apt-get install v4l-utils. Finally i ran sudo reboot to initialize the changes.
And in order to pull the images into ROS, i edited a v4l2 node called usb_cam in order to accept the pixel format that the ov7251 camera uses (Y10). My fork can be found here. In order to install it, (since the docs for the original repo say very little on installation), i ran:
cd ~/catkin_ws/src
git clone https://github.com/ai-are-better-than-humans/usb_cam.git
cd ..
catkin_make
and then after that all you have to do is roslaunch usb_cam usb_cam-test.launch to start the node. Mine started out dark, so i had to go into the launch file and mess around with the brightness for a bit. And while youre there, make sure the pixel_format parameter has a value of Y10
You should get a sensor_msgs::Image message being published to a topic named "<camera_name>/image_raw", you can run rqt_graph to visualize it. Big thanks to 6by9 over at raspberry pi forums, dont think i could have gotten it done without him, he did alot of work that im very thankfull for. Thought id share the knowledge back here in case anyone finds it usefull.
EDIT: I hear you can also compile with catkin_make --pkg usb_cam -DCMAKE_BUILD_TYPE=Release instead of catkin_make if the node takes too much CPU. Also, if you see a ton of error messages while compiling, its fine, it still should work, but if you want to get rid of them you can refer to this answer from a ros thread:
It looks like you need to install libavcodec. I don't know the exact
command to install it off the top of my head, but the format will look
like this:
sudo apt-get install libavcodec
The exact package name might not be
libavcodec. It maybe looks something like libavcodec-VERSION-NUMBER or
libavcodec-dev. In these situations you can search for packages with a
command like this:
apt-cache search libavcodec
This will find all packages that have text
containing "libavcodec". This should find the correct package for you
to install.
I'd like to know if it's possible to extract a binary BSP from a cooked CE image. Obviously I know that you cannot decompile the BSP back into its original form, but all I want to do is change the contents of the userland using the catalog items selector in the platform builder. Is this possible?
A BSP contains sourcecode to boot the system and drivers that are not generic/cross-platform. This is then compiled into binaries and finally the image file is generated. This image file contains the bootable kernel but also a built-in filesystem (the /Windows folder).
If I understand you right, you want to unpack the image, change the content of the built-in filesystem and then pack it up again. This shouldn't be too difficult, but I don't think you will find support for that in PB, so it will require a bit of manual work both for finding the files and the according registry defaults. In addition, adding and removing features might change the cost of your license for the resulting image.
Why can't you just generate a different image? Alternatively, why not simply add the additional software outside the image?
BACKGROUND
I am using a commercial application on windows that creates a drawing
This application allows only two output options: (1) save as a bitmap file and (2) print to a printer
the bitmap is useless for my purposes - I want the vectors
Looking at the print output (I sent to the Windows XPS print driver) it seems clear based on the amount of zooming I can do without loss of detail that the underlying vectors are being send to the print driver
Once I get the vectors, I will be writing some code to transform them for some other use.
MY QUESTION
Whart are my options for geting the vectors from the print? (am open to both commercial and open source)
OPTIONS I HAVE THOUGHT OF SO FAR
Take the bitmap and use a program like VectorMagick to. I have tried this approach. It does not produce the fidelity I seek even when the original bitmap is large. Practically speaking I believe that using any tracing approach will not give me the quality vectors I need.
Print to the Adobe PDF driver. This technically works. I have Adobe CS4 so I can print to it save the resulting PDF and then import the PDF into Illustrator and then export as some other vector format. The problem with this approach is money/licensing. I own a personal copy of Adobe CS4 - so this is fine for me. But I need to capture the vectors at work for business purposes - and no I'm not going to install my personal copy of CS4 at work.
Is there a "print driver" that captures the print output directly into a vector format? I have seen some commercial ones via google. If you've used them, I would like to hear about your experience with this technique. I could write my own and in that case do you have links to any existing code that I can start with.
If this is an ongoing solution you need then you might need to buy something or build your own. If it's a onetime affair you might look to use an 'older' Lexmark PCL printer driver. I'd recommend something like the T610. If you download the PCL driver and install it you can modify the defaults and change the Graphics option from XL or Autoselect to GL/2. This will force the driver to output GL/2 output which is vector (GL/2 is a plotter language). This might do the trick for you. Other printer drivers may have the abiltiy to force GL/2 (vs. Raster) but I'm not sure. I use to work for Lexmark and have used this before for a similar requirement.
Ensure you use the Lexmark 'Custom' driver as I don't think the Microsoft-based one support this feature.
...pausing while I investigate a few things............I'm back...
Another option is to find another GL/2 driver or build you own...I just took a few minutes to search the web and came up with a few other options that might work.
Build you own:
I've built drivers (minidrivers) using the Windows Driver Development Kit (DDK), it's quite simple to construct basic drivers. Looks like there is a setting you can set to enable GL/2 output: Enabling HP-GL/2 Vector Graphics Support (PCL-5e) in the GPD
Alternate drivers:
Depending on the OS you are on there is probably a 'generic' GL/2 driver built in. I believe XP has a Hewlett-Packard HP-GL/2 Plotter. You might need to check the license (as with the Lexmark solution) but it might work for you and as it's part of the OS there shouldn't be concern about using it. It's probably written and copyrighted to Microsoft
Keep in mind you will have to do some work to convert GL/2 to whatever output you want but it should be a matter of an simple translator to convert each set of commands. There may be tools out there to help. Here is a quick link to Lexmark GL/2 reference which might be enough to get you going, check out the GL/2 information under the PCL section: Lexmark Technical Reference Guide
Postscript:
The last option I have is to use a generic Postscript driver. Postscript should output the vector images as vector graphics in the Postscript but my knowledge of this is limited at best.
Output:
If you need the output to route to file you can set the port to FILE: which requries user intervention, or install something like Redmon (or connect with me and I'll send you our port monitor that allows for automatic output to file).
Hope this helps in some way.
My favorite is the open source (GPL) PDFCreator
http://sourceforge.net/projects/emfprinter/
I need to program a util for a 3d model. What i need to do is pass the 3d model to the util and have it extract multiple information. Things like poly count, size/scale (if applicable) and anything else i can grab. Then i need to take a screen shot of the model 8 times (45deg from 0 to 360). Maybe 16. Is there an app that i can use to extract data from the model and is there another app i can use to create the image? if so i can write a php script to do this all for me :) if not i'll post more question about specifics.
My OS is debian etch
the models will be any format. I may make it 3ds only or limit it to what the app(s) support. Or i may have another app to convert one format to the other and extract the data from that format.
I haven't tried this, but you could try 3ds2pov to convert your 3DS files into POV-Ray format, and then render with POV-Ray.
The 3ds2pov program is quite old, so I don't know how compatible it is with current 3DS files. The archive comes with source code so ought to build without too much difficulty on Debian.
POV-Ray itself runs easily on Linux.
nb: other 3DS to POV converters may exist. This one just happens to be the first one returned by Googling for "3ds to pov".
Your requirements are very loose and vague but most 3d engines should have the tools you need to create your custom utility. I would start by looking at Blender or the viewer tools from OGRE, OpensceneGraph and similar tools.
You can try this: Linux based A3dsViewer -> does 3ds to pov conversion.