Tagged Questions
7
votes
2answers
108 views
How to perform enhancement operations on an satellite imagery in QGIS?
I am a new user of QGIS please suggest how to perform image enhancement operations on an satellite imagery like ratioing, contrast stretching, edge engancement, filtering etc. in QGIS?
1
vote
0answers
124 views
Raster satellite images for QGIS
When I try to apply a downloaded GIS satellite (t=rimage to Quantum, it doesn't seem to open properly. There must be a step-by step description on how this would be done effectively. Can anyone tell ...
3
votes
1answer
96 views
gdal_warp of multiple rasters keeping maxium intensity value
I have multiple rasters which overlap eachother geospatially but do not completely occupy the same space. I can combine them with gdalwarp like:
gdalwarp -s_srs EPSG:4326 *.tif larger_output.tif
...
5
votes
2answers
508 views
Creating a multispectral image from scratch
I want to make a multispectral image from cero to do some tests on it. Something really simple like 5 completely uniform bands with salt and pepper noise on them or a square of different values at the ...
4
votes
2answers
140 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 ...
7
votes
2answers
735 views
Poor image quality of raster pyramid files in ArcGIS (no anti-aliasing)
There are several GeoTIFF files (size ~7000x7000 px) which I try to open in ArcGIS Desktop 10.0. I have already created raster pyramids for them (.ovr files) using geoprocessing tool but their quality ...
4
votes
1answer
231 views
Is there any plugin for QGIS to calibrate contrast and brightness of a raster layer?
I frequently need to deal with the contrast and brightness of raster layers in QGIS and I miss the tools in ArcGIS for this task. Should there be a plugin already developed for QGIS? If there is, ...
0
votes
1answer
201 views
Incorrect spatial extent for imported hdf image on ArcGIS
I imported an hdf image onto ArcGIS but I cannot make correct projection of it. Also, it does not have correct spatial extent (please see the enclosed figure, the small one is projected under WGS84). ...
1
vote
0answers
171 views
Assign Custom Band Combination To Image Catalogs In ArcGIS
I have an image catalog composed of 4 band rasters. I would like to use the same image catalog, and set custom renderers for a true color and false color combination and save each of those catalogs ...
11
votes
4answers
375 views
When should I be calling a 'rectangular grid of pixels' a raster or an image?
Reading through GIS literature, it sometimes feels that authors use the two terms with a specific meaning in mind. I always treat the terms interchangeably. Am I wrong?
Read the first line in the ...
5
votes
5answers
3k views
How Do You Remove No Data From A Raster (.sid)?
I have an Image.sid that has a white border which is No Data.
I've tried using Clip Raster Tool with no success.
I've also changed the symbology value for No Data to be transparent.
I'd like to ...
5
votes
1answer
94 views
Non-Research Transportation Raster applications
My experience with rasters is pretty basic. 99.95% of what I do involves vector and transportation modelling. In research, there are numerous transportation applications using rasters and imagery ...
4
votes
2answers
158 views
Unrestricted codec for creating raster files with interior pyramids files
I'm looking for a tool that will allow me to mosaic a collection of images into a file format with performance similar to MrSID or ECW, but without the licensing restrictions that those formats come ...
19
votes
7answers
1k views
Work flow for georeferencing imagery using open source tools?
Does anyone have a recommendation for a work flow for georeferencing high resolution aerial photography using open source tools? Comparison of user friendliness and robustness between Quantum GIS ...
