Questions tagged [remote-sensing]

Collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth's surface or from the atmosphere, or by sensing signals transmitted from a device and reflected back to it.

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37
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7answers
8k views

Machine Learning Algorithms for Land Cover Classification

I am interested in learning what software exists for land classification using machine learning algorithms (e.g. k-NN, Random Forest, decision trees, etc.) I am aware of the randomForest package in R ...
32
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3answers
18k views

How to produce high-resolution DEMs from new Sentinel-1 data?

This is a general question relating to the new Sentinel-1 data. I'm interested in the potential for using this data to create high resolution DEMs in GIS (I use QGIS), to investigate archaeological ...
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5answers
7k views

OpenSource Remote Sensing Tools for Classifying Roofs

with envi image processing and classification tools, you can get roofs from images with some spectral value and then you can convert it some vector data for your app. in python with OpenCV which have ...
27
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6answers
14k views

What is Change Detection and how I can perform such analysis with open source tools?

From wikipedia page: Change detection for GIS (geographical information systems) is a process that measures how the attributes of a particular area have changed between two or more time periods. ...
25
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12answers
20k views

Seeking open source software package for Remote Sensing?

Here are many questions with great answers about open source GIS software. I am wondering, what is the best open source software package for Remote Sensing? I would like to learn it and to use in my ...
24
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6answers
11k views

Is GPS more accurate on specific hours of the day?

I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day. If this is true, how can I get the information on when GPS is more or less accurate at my ...
23
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8answers
1k views

What are people using LANDSAT data for?

Obviously it's potentially a very powerful tool, but I'm curious as to what practical applications people are using it for? Admittedly, this is a very broad question... The reason I ask is because ...
23
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0answers
686 views

SNAP vs. GDAL vs. Orfeo - image rescale, histogram cut

I work with a Sentinel-2 .jp2 image (red band, 10950 x 10950 pixels). My aim is to reach the same result what SNAP does with a Python script. See the SNAP method and parameters: So this is my ...
19
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5answers
6k views

Is there a tool that performs automatic recognition of buildings?

I'm wondering if there is a tool, which takes a satellite map of a region, detects typical buildings and allows the user to review its result (check, whether the tool correctly identified the ...
18
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4answers
13k views

Free GIS software for orthorectification?

Could someone recommend a free and/or open source GIS application that can orthorectify map images?
18
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1answer
32k views

Panchromatic Image association with high spatial resolution

How and Why is a Panchromatic Satellite Image associated with high spatial resolution? I googled and found that it is a single band image, but then why is it called pan-chromatic(All Colors). Does it ...
18
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9answers
7k views

Which Tools do you use for Classification of Remote Sensing Data?

Which tool do you prefer to use for classification of remote sensing data, e.g. classifying land use, and why? Which other tools have you tried, and why did you decide against them?
17
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3answers
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Is there a way to automate the preprocessing of LANDSAT data?

I'm currently enrolled in a remotesensing course, using LANDSAT data. Part of my course is about standardizing the scenes based on radiance values. I assume that because this is such a tedious task, ...
17
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7answers
18k views

Source for high-resolution satellite images free/low-cost?

I am doing a household survey in Kenya, and I need to ensure that my survey team visits every house within a given area. I've been going to google maps and right-clicking on roofs to get coordinates ...
16
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9answers
1k views

What is the best/easiest way to obtain temporal Landsat imagery?

It's been awhile since I've dealt with optical imagery. I need to perform a land cover classification at mid-latitudes using several LANDSAT scenes. I've noticed that some online tools are still ...
16
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3answers
591 views

Why does my rainbow airplane stripes appearing on Sentinel 2 image?

I have downloaded a Sentinel-2 scene and there are some interesting rainbow like stripes trailing an airplane. This is an rgb image but the stripes are also visible on the other bands. You can tell it ...
16
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2answers
845 views

completing satellite imagery tiles when data coverage is less than 100%

I want to join several images (>=2) into one "best" image. Best is defined on low cloud cover and high data coverage. An example using free Sentinel satelite data follows. See http://sentinel-s2-...
16
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4answers
2k 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 ...
15
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3answers
8k views

Which remote sensing satellite is best used for vegetation extent mapping

I'm currently writing an assignment for my remote sensing class and while I think I have correct answer was wondering what people who do this stuff for a living think. The question is: which ...
15
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3answers
1k views

Ecological geospatial conundrum

I am looking for a different, more elegant solution to a spatial statistics problem. Raw data consists of an x-y coordinate for each individual tree (i.e. converted to a point .shp file). Although ...
15
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3answers
14k views

Difference between Albedo and Surface Reflectance

Can anyone tell me what is the difference between Albedo and surface reflectance? I know for sure that they are not the same. Any links / comments are most welcome.
14
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5answers
8k views

Recommended programming language for remote sensing?

I am beginning studies that hopefully will lead to a long career as a remote sensing specialist. I am currently working with ArcGIS for some applications and learning ENVI for others. I have ...
14
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3answers
8k views

Land Cover Feature Extraction from Satellite Imagery

I'm interested in a low-cost or open source solution for creating land cover GIS layers that utilize both spectral and textural extraction algorithms. I have used PCI Geomatica, ENVI, and Feature ...
14
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3answers
5k views

Distinction between pixel-based and object based classification?

I am struggling to clearly understand the distinction between pixel-based and object-based classification in the remote sensing domain and am hoping someone from this community can provide insight. ...
14
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1answer
7k views

Difference Between Radiometric calibration and radiometric correction

I am new in remote sensing field. I sometimes got confused when I read about image pre-processing. Can someone please elaborate to me the difference and some example methods to do radiometric ...
14
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2answers
9k views

How to fill gaps in SLC-Off Landsat 7 ETM+ Images with QGIS?

Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had ...
13
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2answers
14k views

What are LiDAR returns?

Can someone help with an explanation and some references, in order to understand the nature of return pulses within a LiDAR system.
13
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4answers
3k views

Python resource for remote sensing? [closed]

I am looking for a good resource (MOOC, book, etc..) to teach Python for remote sensing applications. I am already familiar with http://www.rsgislib.org/ - are there any other resource out there for ...
12
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5answers
6k views

Extracting tree crown areas from remote sensing data (visual images and LiDAR)

I am looking for a method to process a remote sensing image and extract the crown areas of the individual trees from the image. I have both visual wavelength areal imagery, and lidar data from the ...
12
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8answers
2k views

Is there a smartphone app for mobile asset logging?

I'm after a recommendation for a smartphone app (iPhone or Android) to log asset information for litter bins. I need the following features GPS geotagged photos Form with drop down menus for user ...
12
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3answers
350 views

Distinguishing corridors from fragments in a habitat map

I was wondering if someone has delt with this kind of issue before: I want to delineate fragments based on neighboring pixels of the same class (forest) with a distance threshold of 3 pixels (which ...
12
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1answer
2k views

Reading S3 Sentinel-2 image files with rasterio

I am currently experiencing an 'Access Denied' error after using rasterio to open the Sentinel-2 AWS .jp2 image files (currently hosted by Sinergise and can be found here). My code looks like this: ...
12
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2answers
879 views

How precise are overpass times of sun-synchronous satellites?

sun-synchronous satellites, as their name say, acquire scenes at the same solar time of the day when they pass over the same location. According to this site, sun-synchronicity is achieved by taking ...
12
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2answers
2k views

NDVI in urban environment

What considerations should be taken into account when trying to derive a NDVI from an urban environment? I pulled a tree canopy layer from LAR-IAC data and used an NDVI of 0.38. However, this FAQ on ...
12
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2answers
324 views

Ice type differentiation using satellite data

I would like to classify glacial area by categories of snow (if there is) and ice, but what's most important: between old ice and fresh ice. They have different properties that are possible to ...
12
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1answer
847 views

Frontal Detection of sst & Chlorophyll image

I am working on sea surface temperature satellite images and looking for delineating gradients in open source on the basis of temperature. Is there any tool like Cayula and Cornillon front detection ...
11
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3answers
1k views

Sentinel-2 satellite images not aligning properly

I'm downloading Sentinel-2 tiles from Amazon S3 but they dont seem to be 100 % aligned. Right image is band 08 Sentinel-2 added to ArcGis Desktop (i have done nothing more than adding the 08.jp2 to ...
11
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3answers
4k views

Raw Sentinel 2 jp2 to RGB geotiff

I'm looking for a way to merge Sentinel 2 jp2 band files(B02, B03, B04) and fix RGB colors. All should be done with bash or python script. For my example I work on these images. Ideally the solution ...
11
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7answers
4k views

How to download MOD16 (Modis Evapotranspiration) image?

I use a 'R' script for downloading MODIS imageries. However, it doesn't give MOD16 product. I could neither find the MOD16 product in earthexplorer website. Though the desired product is available at ...
11
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1answer
1k views

How to compare aerial and satellite images for land use analysis?

I am interested to compare the land use-cover dynamics for four periods: 1950s, 1980s, 1990s and current for a certain area having a max size of 5000 ha. For the first three periods detailed aerial ...
11
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2answers
2k views

Extracting roads out of Landsat raster images

For a study into the expansion of road networks in the rainforest I am trying to extract roads out of Landsat images. We already have sharp and cloud-free composites on which the roads are clearly ...
11
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2answers
662 views

How sensitive is Landsat to atmospheric correction?

How important is it to correct Landsat for atmosphere, haze and convert DN to reflectance? What impact does it have on the results, say for many of the vegetation indices?
11
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3answers
3k views

Image processing using Python, GDAL and Scikit-Image

I am struggling with a processing and hopefully I will be able to solve here. I work with Remote Sensing applied to Forestry, especially working with LiDAR data. The idea is to use Scikit-image for ...
11
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2answers
868 views

Is it scientifically correct to pansharpen landsat reflectance product with pan band

I need to know if it is scientifically valid to fuse/pan-sharpen Landsat 8 surface reflectance products with pan band of that respective band? Landsat reflectance product details can be found at here. ...
11
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2answers
4k views

How do you explain that band width and relative spectral response of MODIS band do not match?

To define relative spectral response, I referred to EFFECT OF RELATIVE SPECTRAL RESPONSE ON MULTI-SPECTRAL MEASUREMENTS AND NDVI FROM DIFFERENT REMOTE SENSING SYSTEMS by David James Fleming, 2006. ...
11
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2answers
3k views

Finding Sentinel tile for specific Long/Lat coordinate

I'm building a tool that downloads images from "Sentinel-2 on AWS" I have a trouble translating Long/Lat coordinates to a specific Sentinel tile. I know that Sentinel 2 uses MGRS and I tried to ...
11
votes
1answer
412 views

Automated detection of tracks

Given an area with depressions in open area from; say all terrain vehicles driving on soft surface. The vehicles will cause parallel depressions (paths) of about 10-20 centimeters in depth and around ...
11
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1answer
1k views

Most Effective Format to Manage Aerial Photography for Viewing Only

What is the most effective format to manage aerial photography for viewing in ArcGIS? I manage several datasets of Aerial Photography at a few different companies. I have backups of the original ...
11
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1answer
2k views

How to pan-sharpen Landsat images for image-classification in GRASS?

I'd like to learn how to do an unsupervised classification of a Landsat scene using i.cluster > i.maxlik in GRASS using pan-sharpened 15m-resolution images (the example given in its Wiki uses the ...
11
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1answer
2k views

Multispectral image segmentation for natural-resources applications using R

R has the capacity for image segmentation, although all of the examples I have come across utilize a single band for the segmentation (example). I am interested in combining R's capacity for random ...