Imagery refers to raster based datasets acquired from sensors on satellites or aircraft.
1
vote
2answers
453 views
Where can I find non-rectified stereo satellite imagery?
I'm looking for free (as in beer and as in commercial-use-friendly freedom) sources of stereo satellite imagery. I assume that such imagery should not be rectified since that would remove the benefits ...
4
votes
1answer
267 views
How to identify image location?
I have a satellite image of only one part of some city with a lot of vegetation. I need to find out where is that image taken. I'm interested is there any way to find out where it is taken on Google ...
2
votes
0answers
589 views
Clipping MrSID files
Does anyone have experience subsetting/clipping a large NAIP imagery file in MrSID format? Some of the NAIP files we have are by county and they have really large file sizes.
The files are from the ...
4
votes
1answer
156 views
Which is the best way to create a polygon with the extents of a raster file in QGIS?
I have a tiff image file and want to get a polygon with the extent of the tiff. Is there a direct way of doing this? Right now i have to convert the image to vector (with gdal_polygonize) and then ...
3
votes
1answer
261 views
How can I georeference a second image without losing georeferencing for first image in ArcGIS 10?
What happens:
1) Take a map with an image that was georeferenced earlier, which works fine.
2) Add a second image to the TOC and fire up the georeferencing toolbar.
3) Select the new, ...
5
votes
1answer
258 views
50cm imagery - aerial or satellite?
The area of interest is 1450 km2.
My options are:
50cm newly collected aerial natural color imagery for $28,300
OR
50cm recent archival satellite imagery (includes near IR band) for $20,600
The ...
0
votes
1answer
200 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). ...
3
votes
3answers
926 views
How do I set pixel values to nodata in QGIS?
I have an image which i cliped with an AOI polygon. The contour area was set to pixel value = 0 and I have a nodata value of -32768. I want to redefine the nodata value into zero. I used to do this ...
5
votes
5answers
540 views
georeferencing aerial photos with only known centroid
I have heaps of aerial photos that need to be georeferenced. I have access to ArcMap and ERDAS. All I am given is an excel sheet with the centroid coordinates of each image. Each photo covers an ...
1
vote
0answers
170 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 ...
6
votes
4answers
2k views
Spatial resolution of Google Earth Imagery
What is the spatial resolution of imagery used in Google Earth? At various places on the web, I have been reading it varies from place to place - 60 cm, 2.5 m, 15 m and so on. I was wondering if there ...
11
votes
4answers
373 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 ...
7
votes
3answers
732 views
Use of Pictometry images in GIS
I am wondering if anyone has worked with Pictometry in GIS and their .pmi files. I recently acquired imagery from them for my area and have discovered that I cannot add the pmi files to the webmap, I ...
6
votes
3answers
151 views
Best practices for identifying training sites
Prior to image classification, collection of training sites and obtaining a signature file is the most critical step. Field visits with a reliable GPS Unit is usually the first step followed by ...
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 ...
0
votes
1answer
386 views
Is there a way to save images with none stretching in ArcGIS
I have some satellite images, when I imported these in ArcGIS and went to properties and then symbology tab, I saw stretch type was set to standard deviation. I want to save these images with no ...
1
vote
0answers
226 views
Recomputing footprints on old satellite imagery
I am trying to create an image service out of some 1976 satellite imagery. But first I need to get all of the no data cells out of my mosaic dataset. I have tried to recompute the footprints on my ...
3
votes
1answer
616 views
How to add images containing attributes in QGIS?
I am new to QGIS. I know how to add vector and raster files into QGIS. I have some satellite images taken at different times of the same location. In addition, there are some annotation data ...
4
votes
3answers
304 views
Image viewer or browser for large images
I have some big images. I'm looking for an easy way to browse and view them. Currently I'm using Preview.app on OS X, but it wasn't designed for these types of images.
My images are, for example:
...
6
votes
1answer
540 views
What causes these shiny artifacts in Google Maps imagery?
Do you know what causes artifacts like this one:
Source: ...
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 ...
3
votes
1answer
371 views
WMS Image Services Do Not Display
We recently upgraded to Image Server 10.0.1 and in the process our WMS Image Services quit displaying. The connection to them works in ArcCatalog, but it never displays. If I preview the service it ...
7
votes
2answers
1k views
Does an open source alternative to ESRI's Image Server exist?
I noticed the default way to store imagery is by using a database in the open source world.
I like ESRI's Image Server software because it removes the need for a database and makes backing up a lot ...
4
votes
2answers
142 views
Purple anomaly on imagery
Can someone please tell me what this purple anomaly is on the imagery that we just received. The only thing I have done processing wise is to build the pyramids when they first came into ArcMap. Other ...
10
votes
6answers
823 views
What is this “brown spot” in Google maps?
I was in Google maps today and noticed near Baltimore, US where the river is, there's a huge brown spot. Is this due to all of the waste? If so, will this keep going all the way into the ocean?
5
votes
3answers
714 views
Mosaicing many large ECW files for display in ArcGIS Server apps
I have about 200 ECW files of recently acquired 1-foot resolution aerial photos. Its about 15GB worth, covering over 250 sq. miles. Unfortunately, you need a license from ER Mapper that runs about ...
7
votes
4answers
760 views
How can I work with 3+ Gigabyte TIFF Files?
While I don't work in GIS myself I'm trying to support one of our users here who looks after all our mapping and GIS data. We've received a 3.2GB Tiff image containing satellite imagery of our site ...
2
votes
3answers
159 views
Medium resolution imagery for the US?
For my web map application http://ian01.geog.psu.edu/geoserver/www/pa/pa3.html I have three levels of background imagery as the user zooms in. At small scales I'm using NASA Blue Marble and a large ...
3
votes
6answers
270 views
Source for high-res subscription imagery service
I'm developing a diagramming tool using aerial imagery as a reference layer. This tool should allow the user to zoom in quite close to a roadway or intersection. Unfortunately none of the public map ...
4
votes
2answers
157 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 ...
