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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2answers
972 views

Process of Radiometric Calibration

I am trying to understand the process of Radiometric Calibration of multi-spectral images acquired using Parrot Sequoia sensor with firmware v1.2.1. Given a radiometric calibration target and the ...
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2answers
588 views

Sentinel API query, rows exceeds maximum number

I am trying to query Sentinel1A data using the Sentinel API, by using the following scripts. from sentinelsat.sentinel import SentinelAPI api = SentinelAPI('username', 'password', ...
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2answers
254 views

Sentinel-2A: Begin of operational period?

This also might be of interest here, as it is an important data source: When does Sentinel-2A finally become operational and deliver images regularly? I tried to find information on that, but ...
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2answers
229 views

Removing noise from point cloud with lidR package

I have unclassified Terrestrial Laser Scanning (TLS) point cloud data which has some noise. Is there a function in the lidR package which can be used to remove noise?
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2answers
415 views

Accessing the Quality Band for MCD12Q1 with MODISTools GetBands

I am using MODISTools (https://github.com/seantuck12/MODISTools) to process MCD12Q1 data, which, according to the LP DAAC website (https://lpdaac.usgs.gov/dataset_discovery/modis/modis_products_table/...
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2answers
1k views

Map accuracy assessment by moving window in R

I would like to make an accuracy assessment using a confusion matrix between classified Landsat image and reference dataset. Maps have the same resolution and extent. I would like to evaluate the ...
4
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1answer
335 views

Estimate forest stand height from Landsat imagery?

Is it possible to estimate the height of forest stands using optical (preferably Landsat) imagery? I came across this article while researching this, but it's over 20 years old and there doesn't ...
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1answer
119 views

What proportion of the 240m area sensed by MODIS must be forest before it is defined as forest?

MOD12 is a MODIS product at 240m resolution. Landsat produces 30m resolution products, which I resampled to 240m resulting in a raster of proportion forest cover in each 240m pixel (based on the mean ...
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1answer
2k views

Read Sentinel-2 zip-file into memory using gdal in python

I was wondering if there's a way to read a Sentinel-2 zipfile directly into memory through python without extracting the whole thing or selected contents. I figured since GDAL does have a driver for ...
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1answer
139 views

Is LANDSAT 8 Resolution too low for coastline difference measurement?

I recently extracted coastlines (for my master thesis) for a Bangladesh region for the years 2013 and 2014. Regardless of the method I used, the distance between the 2 coastlines was always the same: ...
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4k views

Difference between Ground Sampling Distance and pixel size in RapidEye

I am a bit confused about reading technical specifications on RapidEye satellites. I assumed that Ground sampling distance (GSD) and pixel size express the same meaning, while GSD is 6.5 m, and pixel ...
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2answers
535 views

Atmospheric correction of Landsat images [closed]

In satellite imagery, isn't cloud removal supposed to be performed while atmospheric correction? My question arises from the fact that even though these Landsat images are atmospherically corrected, ...
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2answers
268 views

“Official” definition to hyperspectral sensor

I was checking in the literature about a formal definition for hyperspectral sensors, and the most complete definition I found was from The Center of Space Research (@ University of Texas in Austin): ...
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1answer
3k views

How to use the same ROI for multiple LANDSAT images in ENVI?

Suppose that I have 3 landsat images with the same datum ( WGS-84 ) and projection system ( UTM, Zone 39N ) as follows: TM LANDSAT 5 image for July 1987 ETM+ LANDSAT 7 image for July 2001 OLI_TIRS ...
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2answers
103 views

What type of remote sensing methodology is commonly used to locate and track the movement of woodland caribou herds?

I am most curious whether it is possible to use Landsat or other freely available imagery (but info on any other method would great as well) to locate and track the movement of woodland caribou herds ...
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1answer
226 views

Does RapidEye level 3A imagery need any kind of preprocessing before applying classification?

I just got some rapideye images and I would like to know if there is need of any preprocessing before applying classification to it? I know that there isn't any automated way of, for example, applying ...
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5answers
2k views

Simple way to collect the Sentinel data of a given ROI?

If you wanted to collect all Sentinel satellite data for a given region of interest (ROI), say, for a given day or time frame - is there any simple way to do it? That means: Without having to download ...
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2answers
496 views

How to correctly parse MODIS QA layers?

I'd like to correctly parse the MOD13Q1 VI Quality layer (see Table 2 in "layers" here). For this, I'm trying to follow Example 1 from this tutorial (page 10). I'll illustrate my problem with a pixel ...
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1answer
356 views

Is the bilinear resampling technique appropriate for the projection of ASTER data?

I need to project some ASTER data from a geographic coordinate system to a projected one. I have read online that the cubic resampling technique is the most appropriate for this purpose. However, ...
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4answers
2k views

Vector Machine Classification in ArcGIS

Is it possible to perform a vector machine classification of raster image using the ArcGIS software package. This supervised classification method is available in the ENVI software but not for ArcGIS. ...
4
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1answer
701 views

Atmospheric Calibration for Landsat 7 ETM+ Gap Filling

This is for thesis work involving mapping of above-ground mangrove forest biomass using Landsat 7 ETM+ imagery. I am assessing correlations between biomass with vegetative indices, e.g. NDVI, and ...
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1answer
735 views

Questions regarding the processing of mosaic Landsat 8

Approximate Translation of Original Question: A question of theoretical and practical about the mosaic of satellite images. I have 3 different months of Landsat images, which need to accomplish the ...
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1answer
668 views

Statistical analyses for survey against raster?

I am somewhat of a newbie to geostatistical analyses, but pretty familiar with GIS and remote sensing packages. I was wondering if anyone had suggestions on appropriate geostatistical analyses for a ...
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2answers
222 views

Remote sensing software options for creating structure footprints from aerials

As shown in screen shot here, just wondering what other software options for creating polygons based on structure footprints are available. Something cheaper than ENVI but still versatile would be ...
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1answer
55 views

Seeking algorithms for DEM generation? [closed]

What are the different algorithms employed for the generation of a Digital elevation model from images captured using an unmanned aerial vehicle ?
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1answer
675 views

Digitizing single land use (agriculture) from raster in ArcMap?

I am working on digitizing the Agriculture land cover in a certain region. I did something very similar before and couldn't find a good alternative method beside manually digitizing, which is utterly ...
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1answer
641 views

Reading subset of GeoTIFF file without having to read whole file first?

I have a set of GeoTIFF files which I have generated from the MODIS LST Product and have used the coordinate information present within the file to work out the index of my 'pixel of interest'/study ...
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2answers
360 views

How to reduce number of raster bands of a RGB picture?

For my Master Thesis in Ecology I want to calculate an NDVI Index. The tricky part is, that I don't have sattelite pictures with bands and so on, but RGB pictures. The pictures where taken with a ...
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1answer
2k views

Accuracy assessment in R - Calculation of User Accuracy

I want to assess the accuracy of the land cover classes classified by supervised classification of Landsat images. As reference data I use the aerial photography. I sampled the classified Landsat ...
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1answer
453 views

what does it mean to store cross products in SAR product data file?

I'm reading the UAVSAR data format For definition of two types of file we have: MLC files (.mlc): calibrated multi-looked cross products, floating point format, three files8 bytes per pixel, ...
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1answer
884 views

How to do change detection between two Landsat scenes?

I want to do change detection and calculate the changes step by step using two images: the first image Landsat 1986, and the second Landsat 2000. Actually I have used image differences in ArcMap and ...
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1answer
674 views

Pansharpening radiance/reflectance of Landsat 8 in GRASS 7?

first at all, I have to say that I'm new GRASS user. I would like to make a pansharp in GRASS 7 with reflectance Landsat 8 bands. I have revised some related posts and blogs, and I didn't find out if ...
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1answer
964 views

How to use a spectral library

I want to classify an Aster image using the ASTER Spectral Library - Version 2.0 Anyone here ever done this? Any suggestions? Note: I'm using opensource GIS and Remote Sensing software Thanks.
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1answer
48 views

Sentinel-1a real azimuth resolution

I was exploring this satellite's payload characteristics on ESA's website and I saw that it's azimuth resolution varies a lot. For example azimuth resolution for IW mode is 22m (https://sentinel.esa....
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1answer
652 views

Landsat / MODIS spatio-temporal fusion: STARFM and software implementations

My main goal is to create Landsat/MODIS image pairs, perform an spatial-temporal fusion which leads to synthetic composites on dates between Landsat acquisition dates. This brought me to the paper ...
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1answer
379 views

Raster pattern recognition

I'm wondering if it is possible to do pattern recognition with QGIS. I have 5 NDVI Landsat images and I try to find areas automatically (constant pattern). Is there a tool in QGIS? The pic below ...
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1answer
45 views

Accuracy assesment of an automatic line digitizer!

I have a polyline map which I extracted automatically and I want to compare it with another polyline map which I extracted manually in order to evaluate the accuracy of the automatic method. (my study ...
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1answer
880 views

NDVI image processing

I am trying to get a NDVI image from an RGB + NIR image captured by a modified Cannon S110 camera bought from Event38 along with a 3DR Iris+ drone link The image captured with the camera looks like ...
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1answer
1k views

Orthogonal correction of building footprints after extracted from a raster

I have ArcGIS 10.1 and am working on a project involving extraction of vegetation and building classes from LIDAR (unclassified) data and aerial imagery (resolution 30x30cm). I have managed to ...
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1answer
523 views

View feature space for multi-band files

I am trying to plot a feature space (scatter plot) for some SPOT images in QGIS 2.8.1. I know a histogram is available in the file properties, but I want to plot eg. Band 1 vs Band 2 to see the ...
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1answer
1k views

Python script for dark object subtraction on Landsat 8 Imagery

Does anyone know of any python scripts that will allow me to conduct such a process? I am limited to open source software and have minor experience in Python.
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1answer
797 views

How to extract impervious areas from Landsat data?

I'm working with multi-temporal datasets from Landsat (Landsat 8 & Landsat 7 & Landsat 5) and I tried to extract impervious areas, more exactly urban areas, but I can't obtained results very ...
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2answers
1k views

What does MODIS data reflectance values (MOD13Q1) mean?

Several publications suggest filtering MODIS data (in my case MOD13Q1) prior to use. They recommended to filter out pixels having blue reflectance more than 10%, but what 10% here means? is it 10% of ...
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1answer
428 views

Open Georreferenced MODIS L2 atmospheric data in python

i'm working with a MOD04 (atmospheric product) but i don't know how to georrefence the image in Python. I'll show an example of a code opening the Optical Thickness product #==========================...
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1answer
203 views

Why are Landsat 8 files on AWS compressed cf those from USGS?

I want to shift from downloading Landsat8 imagery directly from USGS to the AWS service (https://pages.awscloud.com/public-data-sets-landsat.html). I have some automated processes that are not ...
4
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1answer
339 views

Band combinations for identifying limestone quarries

What are the most useful band combinations for identifying current and recently closed limestone quarries (Landsat 5 and Landsat 8)? In particular, for a dry sparsely vegetated region like much of ...
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1answer
442 views

Is there a way to use the GDAL C++ API to find areas of overlap between two SAR images?

I have a bunch of SAR images (about 1 GB each) on which i need to do some image processing. Each image is georeferenced and there is significant overlap between each pair of images in the set ie. one ...
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1answer
33 views

Defining city name by using KMZ files

We have KMZ files of different satellite images. We want to check which cities these satellite images belong to. Is there a way to do it automaticly? Like a tool in ArcGIS or QGIS or whatever?
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1answer
795 views

Differences between mWm-2sr-1(cm-1)-1 and W/m^2 * sr * um

I'm confused about the use of this quantity. For example eumetsat on pag. 16 radiance is equal to: Physical Units = Cal_Offset + (Cal_Slope x Level 1.5 Pixel Count) expressed in mWm-2 sr-1 (cm-1)...
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1answer
374 views

Which preprocessing comes first for pansharpened imagery- atmospheric correction or orthorectification?

For pansharpened imagery, what preprocessing method to do first- is it atmospheric correction or orthorectification? From my readings, it seems the former but the rational polynomial coefficients or ...