Questions tagged [compression]

The encoding of digital information in order to store it using fewer bits.

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Reducing the accuracy of coordinate data

Let's say that I have a large set of latitude, longitude pairs which are accurate to 5 meters. I want to reduce their accuracy to 100 meters so that they render quicker and consume less storage space. ...
Rip Leeb's user avatar
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Problem with rendering jpeg compressed image - Caused by: java.lang.ClassNotFoundException: org.libjpegturbo.turbojpeg.TJException

I have a problem with rendering GeoTiff image that is jpeg compressed image. It's size is about 50MB but uncompressed it is 1200MB. This is what gdalinfo command tells about compressed image: ...
Milos Miletic's user avatar
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1 answer
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Zipping up a shapefile [closed]

I know this may be a topic for Stack Overflow, but it might be worth answering here as it related to shapefiles. I am trying to zip up a shapefile. I have selected all the components of the shapefile ...
MacroZED's user avatar
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2 votes
1 answer
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Compress Raster in ArcMap without generating a new File

I have several uncompressed rasters (FGDBR format) stored in a File-GDB. Now I want to compress this data. The only way I know is to use the "Copy Raster" tool but this will generate a new raster with ...
Simon's user avatar
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2 votes
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4 Band JPEG2000 compression for RGBNIR

The South African National Mapping Agency acquires multispectral imagery (R,G,B and NIR)and currently compresses its aerial imagery with JPEG compression with a TIF wrapper. So we give out JPEG (Q3) ...
Aslam Parker's user avatar
1 vote
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177 views

ArcGIS Raster Shows No Compression

I am using ArcGIS 10.2 to add raster layers to a geodatabase. When I create a new 32-bit floating-point raster layer, I specify that it should use "Packbits". After the layer is created, I check ...
Richard's user avatar
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3 votes
1 answer
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Compress Raster Overviews

I have a large number of Raster Aerial images which I have been building VRT files for. I'm also building overview for them with the following code gdaladdo -r average -ro Y:/vrt/sussex_2016_aerial....
Matt Pitts's user avatar
2 votes
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Reading Jp2 compression level using ArcPy? [closed]

Is the compression quality level used to create a JPEG2000 image stored somewhere inside the file, and how to read it? I would like to know if my images where generated using a lossless compression ...
stef's user avatar
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5 votes
2 answers
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How to find fluctuant parts in a trajectory

I am currently doing an assignment on how to compress a trajectory. Given a trajectory T1 in figure 1, and I want to get a compressed version as T2. For segments p0~p3 and p6~p9 in T2, I can obtain ...
Guan Yuan's user avatar
1 vote
1 answer
164 views

How do I keep my python loop going if there is an error with an SDE workspace?

I have a folder with several .SDE connections. I want my Python code to execute various SDE maintenance procedures (such as compress) on each of these databases. If there is a bad/corrupt/not ...
CD4's user avatar
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Knowing byte address and byte length of "strip" in LZW-compressed GeoTiff with vanilla PHP?

I have a situation where I need to read cell values from a GeoTiff using vanilla PHP, and while I've been successful reading values from an uncompressed TIF (~800MB), I'm having difficulty reading ...
elrobis's user avatar
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How to configure Apache for topojson gzip files [closed]

Building an online interactive map with leaflet and some heavy layers with my spatial data in topojson format. I have been reading about gzip but I am still uncertain how to configure it. Do I need ...
leviwest's user avatar
2 votes
1 answer
527 views

How to remove compression from jpeg2000 NAIP imagery?

I downloaded a 4-band 1m spatial resolution NAIP image from Earth Explorer. The default image format is jpeg2000. You can see the trees in the attached image appear grainy, more so than what you ...
Aaron's user avatar
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1 vote
1 answer
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Extract multiple tar.gz files [closed]

I'm new here and in the world of Python scripting mostly with the arcpy module. I hope you can help me with the trouble that I have. I'm trying to develop a script to extract or uncompress multiple ...
jpdelped's user avatar
2 votes
0 answers
234 views

TileStache PNG Optimization

A Tilestache config file has a "png options" object that passes its config straight through to the Python Imaging Library (PIL). Setting optimize: true does some kind of optimization as the file is ...
DMack's user avatar
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925 views

Compression Algorithms output files larger than the originals. Why? [closed]

I'm currently attempting to write a script that will compress a few hundred .tif files. I've tried two approaches, first I wrote a script in Python using CopyRaster_management() function and the ...
purelyp93's user avatar
1 vote
1 answer
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Python Script to batch compress .tif files using LZW compression

I am currently trying to batch compress a folder of .tif files using LZW compression in order to free up storage space. I've been using this script in ArcMap's python window, adapted from here: # ...
purelyp93's user avatar
1 vote
1 answer
2k views

How to unzip multiple folders with FME 2014

I have downloaded 21 zipped folders using the HttpFetcher transformer and I cannot figure out how to get FME to unzip these files. I've seen some posts about using either the TclCaller or ...
Daníel Örn's user avatar
3 votes
3 answers
294 views

Bad SRTM files?

I have noticed that between 1-3% of SRTM .hgt files downloaded for a continent when un-zipped are of TGA image, font image or text format and do not contain elevation data. Results are the same ...
pitney's user avatar
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1 vote
0 answers
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Subsetting image such as NAIP? [closed]

Has anyone any luck subsetting a small part out from NAIP? I seek your feedback on pros or cons of how to subset an image from NAIP despite they are in mrsid and their uncompressed file size are ...
PROBERT's user avatar
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5 votes
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Save map in raster format from QGIS using compression

Is there a method to save a map in raster format from QGIS using compression? For exemple from "Export map" in ArcGIS there are many options to compress the images depending on the file type (tiff, ...
toWGS84's user avatar
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10 votes
5 answers
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Raster diff: how to check if images have identical values?

Is there a means to check to see if any 2 given raster layers have identical content? We have a problem on our corporate shared storage volume: it's now so big that it takes over 3 days to conduct a ...
matt wilkie's user avatar
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1 vote
1 answer
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Compressing multiple static layers to single layer to make web map loading faster?

In our web application there are many layers to be loaded, this cause the loading of map very slow. I am seeking a way to compress multiple static layers to a single layer to make the loading faster....
ppLily's user avatar
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14 votes
5 answers
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Methods for geohash of polygon?

GeoHash is an excellent method to code the latitude and longitude of a point into a string. It's concise, due to the use of numbers + letters, and the precision can be tuned adding characters at the ...
Sylvain Lesage's user avatar
1 vote
1 answer
2k views

ERDAS Imagine ecw compression settings

We have some jp2 or img satellite images that we compress to .ecw using ERDAS Imagine. We have realized that with some images we are losing too much information while doing that. What i wanted to ask ...
Yasmin's user avatar
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3 votes
0 answers
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Why does compressed & zipped/unzipped file geodatabase give Open Failed Error opening feature class Cannot access secured data?

In ArcGIS 10.2 for Desktop, a colleague compressed a file geodatabase and then zipped it and sent it to me via email. I unzipped it and was unable to add any of the feature classes into my map ...
user28611's user avatar
1 vote
1 answer
2k views

When trying to convert an .e00 file into a shapefile with ogr2ogr, getting "ERROR 4: This looks like a compressed E00 file"

When I ran this command: ogr2ogr topo.shp flowe86hyp.e00 I got this error: ERROR 4: This looks like a compressed E00 file and cannot be processed directly. You may need to uncompress it first ...
boulder_ruby's user avatar
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12 votes
1 answer
4k views

What does the predictor switch do while compressing GeoTIFFs in GDAL

I am merging several GeoTIFFs into one and am using the -co COMPRESS=DEFLATE create option for GeoTIFFs. An additional switch is the predictor switch. What does it do? The GDAL website is not clear on ...
Freeze's user avatar
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2 votes
2 answers
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How to compress raster image for publishing?

I have a (8-bit) satellite image that is e 6 gb. Is there a way I can compress the image smaller size without losing the quality? Format: .tif Reason: After publish the image, I notice a higher usage ...
seesee's user avatar
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6 votes
2 answers
3k views

How can I reduce the size of my file geodatadase?

We're using file geodatabase for tax mapping. we save building photos and there are 6000 buildings. The size of this data 2GB. So loading the data takes a lot of time we are not unable to do work ...
Govindaraj R's user avatar
6 votes
2 answers
890 views

Wavelet vs Discrete compression for imagery

What is the main reasons to choose wavelet (jp2, sid, ecw) instead of discrete (JPEG) compression methods for raster data? Lets limit this question to aerial imagery and lossy compression. Why ...
Alex Markov's user avatar
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5 votes
1 answer
3k views

Using PNG/JPEG Compression in GeoServer

Is there any use in setting the PNG and JPEG compression in GeoServer (Services - WMS - PNG Options/JPEG Options)? The default is 25, but we heard rumours that having compression resulted in a time ...
Rob Quincey's user avatar
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3 votes
0 answers
155 views

Classify trajectory compression algorithm

I'm tryng to classify each compression algorithm based upon their features, i've thinked: Compression algorithm Lossless algorithm Batched algorithm Rinex Lossy algorithm Batched algorithm ...
BAD_SEED's user avatar
  • 381
1 vote
2 answers
660 views

Open MapGuide MrSID rasters with FDO GDAL. invalid extent. Not drawing

When I try and save the resource I get: Spatial context extent appears to be invalid (or Default). The XML: <?xml version="1.0"?> OSGeo.Gdal.3.4 Default This coordinate system ...
Zap Rowsdower's user avatar
0 votes
1 answer
411 views

Create moving map application from topographic maps

I'm trying to create a moving map application for an embedded ATOM device. Data source is a 400MB tif file (500dpi) plus projection and worldfile. My naive approach was to load that tiff into Global ...
user avatar
69 votes
8 answers
37k views

Should GDAL be set to produce GeoTIFF files with compression? Which algorithm should be used?

I have a folder of GIS data that consists mainly of GeoTIFF files. The whole set weighs in at about 1.2 GB. I noticed that if I pack the contents into a tarball, it smashes down to about 82 MB. I ...
Sharpie's user avatar
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