Imagery refers to raster based datasets acquired from sensors on satellites or aircraft.

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24
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7answers
2k 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 ...
13
votes
3answers
1k views

Is there a programmatic way to retrieve Landsat 8 Satellite Images?

I have not been able to find out this myself, but is there a way to programmatic access Landsat 8 Satellite Images? I know that I can go to USGS EarthExplorer to search and browse through the scenes, ...
6
votes
1answer
1k views

What causes these shiny artifacts in Google Maps imagery?

Do you know what causes artifacts like this one: Source: ...
1
vote
1answer
1k views

How to adjust online basemap to Arcmap

How can I adjust the online basemap imagery file to our existing ArcMap data. Below are steps I perform to add the basemap data. I Added basemap from "Add Data From GIS Online" in the file menu and ...
14
votes
3answers
653 views

Alternative vegetation indices

I have been using NDVIs with limited success to identify trees in the central Great Plains region of the USA. The problem I have been encountering is that reflectance from farm fields/pastures have ...
5
votes
5answers
1k 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 ...
2
votes
2answers
233 views

SPOT NDVI time series

I have 423 spot.vgt ndvi from first April 1998 till 31 Dec 2009. I want to know how to stack these NDVI to have one image for time series analysis? Or better to ask how is it possible to analyze a ...
5
votes
2answers
403 views

Extract certain area of contours/satellite images

I have 2 satellite images (jpeg2000 format) and 2 xyz-files from the same area. I am trying to extract certain region from the area including contour lines and the satellite image in order to import ...
2
votes
0answers
572 views

Automated testing for GIS apps

There are several commercial and opensource tools for regression automation. While many of them could be employed to test GIS apps, they fall short, at times, dealing with the unique characteristics ...
2
votes
1answer
889 views

Convert 3-band raster imagery to distinct vector zones in ArcGIS

So much like the title says I would like to convert a 3-band infrared image TIF file of vegetation into distinct vector feature zones using ArcGIS. I'm guessing the only way to do this is with ...
1
vote
1answer
416 views

TRMM data download

I need help in downloading 7 day composite TRMM data (Geo-Tiff) like this for past 10 yrs of the SE ASIA region. It is way too confusing where to obtain the data, I wanted to analyze the precipitation ...
1
vote
0answers
135 views

Load MrSID file in QGIS 2.2 on Ubuntu 13.10

Is there a way to do this? I have tried a number of the write ups on this, and it appears that libgdal-mrsid-src no longer exists. Is there any other workaround? USDA NAIP imagery is sent as MrSID.
6
votes
2answers
274 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 ...
5
votes
1answer
852 views

What lens and camera settings are recomended for UAV (drone) aerial imagery capture? [closed]

I have been toying with the idea of purchasing/bowrrowing a UAV and attempting to capture my own aerial imagery. I have pretty good DSLR Canon gear and several lenses but I am wondering what lens, ...
5
votes
2answers
276 views

Pictometry Accuracy and/or Alternative

I'm looking for some insights into the accuracy (x,y,z) of oblique imagery from Pictometry in terms of providing accurate measurements for property evaluation. Is the high cost of this product ...
3
votes
2answers
130 views

Geographically georeference image with limited information

It is possible to semi-accurately georeference an image given only the following information? I'd like to do this programmatically. Center point of terrain, Lat/Lng (WGS84) Pitch of camera FOV ...
3
votes
1answer
1k views

Clipping MrSID files in ArcGIS Desktop?

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 ...
3
votes
4answers
3k views

How to redefine the nodata value into zero 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 ...
2
votes
2answers
804 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 ...