i would like to import a tiff file to postgis using gdal and java.Is that possible to store raster files in db like this?
Related
Currently, my app creates GeoTiff tiled files using following options:
PROFILE=GeoTIFF
TILED=YES
BLOCKXSIZE=xxx
BLOCKYSIZE=xxx
COMPRESS=JPEG
PHOTOMETRIC=YCBCR
JPEG_QUALITY=xx
However, some apps that use my served tiles do not work due to "invalid" JFIF format.
How can I force gdal to ensure JFIF format in GeoTiff tiles?
See my own answer in https://gis.stackexchange.com/questions/426732/generate-jpeg-ycbcr-tiles-in-geotiff-file-with-jfif-format-instead-pure-jpeg-for/428023#428023.
Basically, solution involves gdal code modifications
I am trying to add three.js based 3D objects to a PDF page. It seems there are no direct exporters available to do that. So I am trying to do the below thing,
Convert the gltf/stl/obj files to U3D files
Add the .u3d file to PDF page.
I am trying to do the below process and I am not sure whether this approach is possible. It will be a great help if there is any support available to do any one of the below conversions. Also if you know any other possible approaches, kindly update me!!
Input formats output format
GLTF
OBJ U3D
STL
(any
three.js supported
3D formats)
Thanks.
There are few options available to export the three.js graphics to a PDF ( static content not a dynamic U3D assets)
Static contents
Get the rendered data from the three.js webGL renderer / canvas renderer using toDataURL("image/jpeg"), change the MIME type to JPG/PNG and add the resulting stream as an image to PDF ( this worked for me)
example - https://plnkr.co/edit/Ty8BZaDcflCJH5tH?preview
Like the above approach we can use three.js svgrenderer to export the renderer contents into a SVG data stream, which can be added into the PDF ( textures, mesh may not be 100% reproduced)
The legacy API - "threejs-pdf-renderer" can be used to directly export the three.js animations to a PDF. We don't need any other dependencies to create the PDF. But this is a legacy API which uses legacy three.js version, lot of effort needs to be done to make the API to be compatible with the latest three.js version.
example - https://satheeshks10.github.io/ThreejsPDFGenerator/
Dynamic 3D contents
We can export the three.js animations into a U3D file (no direct support is available as for now), this U3D file can be directly embedded into PDF.
example - https://tetra4d.com/pdf-samples/
I am programming in Python, but if some tool/library exists in another language that would help me considerably, I am open to suggestions.
I have a large collection of pdf pages that live in a database, and I am trying to automate the collection of those pages to build some image recognition models with them.
These "pdfs" are actually just PNG images encased with a PDF wrapper (presumably so they can be read by PDF readers like Adobe Acrobat). I need the pdfs in image format to feed into the image recognition model pipeline. I am assuming they are PNG images, because when I save the images from the browser (i.e., right click and save image as), the resulting file is a PNG file.
After reading this question from 2010, and checking out this blog post from 2007, I've concluded that there must be a way to just extract the PNG byte array from the PDF instead of re-converting the PDF into a new image. Oddly though, I couldn't find the PNG file header with
#Python 3.6
header = bytes([137, 80, 78, 71, 13, 10, 26, 10])
#the resulting header looks like this: b'\x89PNG\r\n\x1a\n'
file.find(header)
Does that mean that the embedded image is not in fact a PNG image?
If there is no easy way to extract the embedded image byte array, what tool might I use to automate the conversion of each PDF file to some image format (preferably JPEG, PNG, or TIFF)?
Edit: I know tools like ImageMagick exist for format conversions, but I'd really rather do the extraction method for the sake of learning more about these file formats.
pip install pdf2image
pip install pillow
pip install numpy
pip install opencv-python
Then,
import numpy as np
from pdf2image import convert_from_path as read
import PIL
import cv2
#pdf in the form of numpy array to play around with in OpenCV or PIL
img = np.asarray(read('path to the pdf file')[0])#first page of pdf
cv2.imwrite('path to save the image with the file extension',img)
Is there way to convert three.hs as U3D to 3D pdf?
I want to export assembly I have as three.js to 3d pdf based on tree structure (children of children).
Is it possible?
Something opposite to Convert Adobe 3D-pdf to WebGL?
We have lately done some experiments ObjExporter (amended to also export the container colors). By the same method you can also import STL Files, but then we have not found a way to transfer the colors.
The obj/stl file are then transformed to U3D files with Meshlab.
These U3D files then can be transformed with miktex/latex into 3D pdfs(see here). The system also can run on a server with some batch script.
I'm trying to read JPEG2000 images in Magick++ (the C++ API of ImageMagick). To read an image I use the following code:
Image img("path/to/my/image.jp2");
But when I try to do this, ImageMagick throws an Exception and doesn´t load the image.
I extract the images out of PDF files. Could it be that something´s different to normal JPEG2000 images? To extract the images I read the stream of Image objects which have a JPXDecode-filter and save them to a file.
Hope someone can help me!
ImageMagick uses a package called JasPer to handle JPEG2000's. According to the wikipedia page on OpenJpeg, JasPer does not completely support the JPEG2000 specification. I have several extrected JPEG2000 that open fine in QuickTime, but fail to decode with ImageMagick.
I have had better results using OpenJpeg to decode the the Jpeg2000. The interface is less flexible, it will convert to PNG and BMP.