All Questions
303 questions with no upvoted or accepted answers
11
votes
0
answers
1k
views
What is the convergence threshold for ArcGIS Iso Cluster?
The ArcGIS tool Iso Cluster Unsupervised Classification does not seem to have any documentation on the convergence threshold used in the tool. To compare, Erdas Imagine has all of the necessary ...
5
votes
0
answers
2k
views
Cropland field delineation using OpenCV and Google Earth Engine
I want to follow the methodology in the following article in order to find field boundary delineation automatically: "Multi-Temporal Crop Type and Field Boundary Classification with Google Earth ...
5
votes
0
answers
714
views
Error with ROI Semi Automatic Classification Plugin QGIS 3.4
I have troubles for making ROI with SCP plugin in QGIS 3.4.
I dowloaded some landsat images with the plugin and trying to create ROI. To do it, I made a Bandset with DOS1 atmospheric correction, ...
4
votes
1
answer
945
views
Predicting the whole image through trained classifier and visualize it as classified landuse and landcover image(LULC)
I am working on LULC classification of Sentinel-2 image(4-bands) using Machine Learning algorithms. I split the whole image into 64*64 patches and assigned class label (builtup, barren land, water and ...
4
votes
0
answers
1k
views
Sentinel 2 preprocessing with R
I need to transform Sentinel 2 L1C imagery to preprocessed Level 2A data.
Ideally this should happen in R, as the remaining processing stack is already done in R.
Are there ready preprocessing ...
4
votes
0
answers
379
views
How to increase Compression Memory for ECW Opacity Builder
I am attempting to build opacity within an ECW file using ECW_Opacity_Builder.exe from APOLLO Essential Utilities 2014, which has worked flawlessly many times before.
When attempting to build opacity ...
4
votes
0
answers
2k
views
Classify image using segmentation analysis using QGIS and OrfeoToolbox
I am working on a project where we have made a RGB orthomosaic using a drone which I want to classify using QGIS. I am not a fan of unsupervised classification, and I started exploring the ...
4
votes
0
answers
756
views
How to remove black pixels in Landsat image
Does anyone know how I can remove these black pixels around the edge of this Landsat image? They appeared when I layer-stacked the bands in ERDAS IMAGINE - they were not there in the separate band ...
4
votes
0
answers
693
views
What does "Information [18]: Select at least one signature" in the semi automatic classification plugin mean?
I am using the semi automatic classification plug in to classify vegetation and water in a satellite image. I create training shp and signature list. When i hit "classification preview" it gives me ...
3
votes
0
answers
329
views
Alternative for Normalized Difference Built-up Index (NDBI) using satellite imagery with RGB & NIR bands
I am currently working with Planet SkySat multispectral imagery in Google Earth Engine (dataset description). It has only Red, Green, Blue and NIR bands. My objective is slum mapping and for this, ...
3
votes
2
answers
253
views
Error occurring when converting to dB during the python-based classification
I am trying to perform an object-based classification using a python-based script with rsgislib. Although, when converting to dB, an error is appearing. Any ideas why is this happening?
Create and ...
3
votes
0
answers
60
views
Is it possible to detect human settlements by night light data?
I am working on a project in which human settlements are identified using geo-tagged Twitter data. Since this project is focused on developing countries (mostly African), I am afraid that many human ...
3
votes
0
answers
717
views
authentication error for accessing data product on scihub through wget
I am new to Sentinel(overall remote sensing domain) and currently trying to download the data products from Scihub using the wget utility on Windows10 machine. However I am getting the below error. I ...
3
votes
0
answers
791
views
Aligning raster layers in python script
I am wanting to automate the preparation of raster layers from Sentinel-2 to be used in an unsupervised classification. So far, I have been able to write the following script, which will successfully ...
3
votes
0
answers
273
views
Extracting cells from raster by attribute in ERDAS Imagine
I have a raster file that gives me the slope of all the hills and mountains in an area in degrees (0-90) and I need to extract all the cells which are >= 45 with an operator in the model builder. I ...
3
votes
0
answers
636
views
Negative reflectance values after topographic corrections (cosine correction and modified Minnaert correction)
I am trying to manually correct the surface reflectance values of some Landsat 7 and 8 images. I'm using Minnaert modified method, which uses the cosine correction as one of its inputs (see below the ...
3
votes
0
answers
514
views
MODIS Imagery Orthorectification (Open Source)
I am looking for an open source free software/tool for orthorectification/Geometric terrain correction of MODIS imagery.
I have looked at ESA (European Space Agency) SNAP but this sensor type is not ...
3
votes
0
answers
370
views
Import GPS SINEX (for velocity analysis) into Sarscape or processing with others software
I try to import GPS snx. into Sarscape 5.2 (use GPS Import tool) and getting error
115) ) gps_type : [sinex]
116) ) generate_kml : [OK]
117) ) generate_shape : [OK]
118) ) ...
3
votes
0
answers
94
views
Guide to aerial or space data types and availability
I am overwhelmed by the variety of types of satellite and aerial data (images?) available online. For example, at the USGS Earth Explorer data page, I see AVHRR; CEOS;Ikonos and OrbView; EO-1; GLS; ...
3
votes
0
answers
80
views
Should Endmembers be Normalized for Linear Unmixing?
In biological spectral microscopy, the standard in the field is to use normalized endmembers in linear unmixing algorithms. In most cases, the endmembers are normalized to the maximum value. I have ...
3
votes
0
answers
386
views
Landsat TM, ETM+: what are radiometric calibration coefficient of each sensor to convert DN to radiance
The Landsat TM Image data that comes with zipped folder contains metadata text file in which all necessary information have been written. In order to further process that data, first DN to radiance ...
3
votes
0
answers
395
views
ASTER mineral indices with VINR and SWIR data
I need to run a supervised classification on ASTER data in order to map a rock formation, which is composed of chert. There is no shortage of indices which can be used to highlight silica rich ...
3
votes
0
answers
472
views
R: Can raster predict function pass to predict.rfsrc (a prediction function in a parallel verion of RandomForest)?
It seems that raster predict function can pass to predict.randomForest by setting the "type='response'". I am using a parallel version of randomForest package called the "randomForestSRC" and I am ...
3
votes
1
answer
2k
views
Using Python script to stack layers from multiple directories and produce multiple outputs in ERDAS?
I am using ERDAS Imagine 2013 and am trying to create a Python script that takes lists created in another script containing the path to each scene's raw data folder and base image ID's (for example ...
3
votes
0
answers
3k
views
Interpreting NDVI value on water?
There is a surreal thing on my NDVI images. NDVI values on lake is ranging from -0.04 to 0.7. (The lake surrounded by forest and has freshwater). Theoretically, negative value of NDVI is correspond to ...
3
votes
0
answers
3k
views
Principal Component Analysis in QGIS
How do I go about to perform a band ratio and Principal Component analysis in QGIS? I need to derive principal components from ratios of landsat TM bands .
3
votes
0
answers
603
views
Localized Linear Histogram Match using python
I would like to use the local linear histogram match for filling the missing pixels of a Landsat 7 image with another older image (SLC Gap-Filled Products).
Do you have any idea how can I do it by ...
2
votes
0
answers
312
views
Properly configure image segmentation on QGIS (Segmentation / MeanShift)
I'm trying to perform remote sensing on georeferenced historical satellite images (taken from Google Earth), using the segmentation algorithm from OTB.
In the parameters of the Segmentation algorithm, ...
2
votes
0
answers
127
views
Using images from different Landsat missions and Sentinel-2 for machine learning
I am doing some image segmentation using random forests on satellite imagery. The events I am trying to detect are somewhat rare so my training sets are very limited if I want to use Sentinel-2 ...
2
votes
1
answer
542
views
GEE: projection error when exporting data to a table
I am trying to export some vegetation condition index data calculated from MODIS data on Google Earth Engine to a table, but keep getting the error:
Error in map(ID=3): Image.reduceRegions: Unable to ...
2
votes
0
answers
65
views
Extract lines of rice terraces from satellite image
I have a Pleiades image and multiple rice field boundaries in a shape file.
What I want to do is for every feature in the shape file, clip the Pleiades image and detect the lines of the field terraces....
2
votes
0
answers
118
views
Do PNG files suffer performance for scaled read over ERDAS Imagine (.img) files?
So I have a 20 GB in size Raster Image in .img format. Though I will be examining the code, to find out why, I am AMAZED at how quickly QGIS renders the entire file in a scaled format, and prior to ...
2
votes
1
answer
494
views
Exporting EVI image on Google Earth Engine with visual parameters between -1 and 1?
I am having an issue with exporting an EVI image with the visual parameters between -1 and 1. On Google Earth Engine (GEE), using the inspector tool, the values are between -1 and 1, but when I export ...
2
votes
0
answers
66
views
Solving color correction of LISS IV Multispectral image
I have a LISS IV multispectral images (radiometric resolution of 10 bit per pixel) taken in different months 4 tile in January and 2 tiles taken in February.
While mosaicing, I got a different color ...
2
votes
0
answers
204
views
Calculating proportion of pixel containing vegetation (from sentinel 2 image stack)
My task is to perform a supervised classification of landcover across a huge (20,000+ hectare) property. I need to classify into three classes: forest, regenerating trees, and soil. We use s
Sentinel-...
2
votes
0
answers
694
views
Layer stacking Multispectral reflectance imagery in ERDAS Imagine 2016
I have Green, red, Red edge and Near infra-red reflectance maps captured with a Parrot Sequoia camera and post processed with Pix4D.
They are all Single Float Tiff files, around 500Mb in size.
I ...
2
votes
0
answers
97
views
Calculating indices by Multiple polygons
Is there a way in QGIS to perform band math within each area defined by different polygons without clipping the rasters and performing calculations on each one?
I have a vector layer with several ...
2
votes
2
answers
832
views
Projection shapefile
I created a shapefile of Sundarban area Bangladesh. Here it is:
Here is the projection information about it:
I want this shapefile to project upon an image which is here [I downloaded it from ...
2
votes
0
answers
483
views
NDVI calculation problem
I have photo created by UAV, and I want to calculate bNDVI:
(NIR-blue)/(NIR+blue)
I have these bands (filter is ok -100%). So using QGIS I have values -0,1-> 0,3 - but bNDVI must be from 0,65->0,...
2
votes
2
answers
3k
views
ENVI band math incorrect values
I'm attempting to calculate vegetation indices in ENVI 5.2 using level-2 AVIRIS data in band math.
The indices I'm working with are Vogelmann Red Edge 2, normalized difference red edge, and red edge ...
2
votes
0
answers
240
views
Supervised classification using endmember spectra (using ENVI 5.1)
We are trying to map land cover classes over a small watershed. We have selected training sites (during a field campaign in early 2017) and determined their spectral profiles on a Landsat 8 image ...
2
votes
0
answers
51
views
Register an image using mutual information
I want a procedure for registering two images based on their mutual information. I took a pair of georeferenced radar images of the same location, edited the metadata of one so its position was off by ...
2
votes
0
answers
112
views
Is there an arXiv-like electronic archive used by the remote sensing community?
Mathematicians, physicists, and (theoretical) computer scientists use arXiv extensively to share their preprints. Indeed, one could say that it's the established way to share one's research.
Is there ...
2
votes
0
answers
355
views
ENVI shows colors of different RGB code the same in a bitmap image wrongly?
As you see in this picture which I've captured in MATLAB, there are two colors.
Red with the RGB code (255,0,0)
Brown with the RGB code (138,139,1)
I've tried to show the same picture in ENVI, ...
2
votes
0
answers
227
views
Image classification: separating pine forest, lowland and upland hardwood
I want to classify 20 feet-resolution 4-band leaf-off image into lowland hardwood, upland hardwood, pine trees, and other (bare ground, water, roads etc). I am thinking to use randomForest package in ...
2
votes
0
answers
58
views
eCognition - prevent rounding of raster values?
I have a WorldView2 image, which I would like to segment and classify in eCognition. The image has been pre-processed to Top of the Atmosphere Reflectance, therefore hasvalues between 0-1.
The ...
2
votes
0
answers
143
views
Improving FLAASH atmospheric correction to accurately represent subtle features in a target's spectral profile?
I am attempting to use ERDAS target detection models to detect/differentiate a specific type of soil from a general background. We have gathered spectral signatures of the target soil in the field ...
2
votes
0
answers
212
views
i.atcorr - Landsat 8
I am trying to apply atmospheric correction to Landsat 8 scenes using i.atcorr. After tons of tests I am still struggling with the correct input and output range.
The results deriving from radiance as ...
2
votes
0
answers
217
views
Erdas 2014 process time signature editor supervised classification
I am currently using erdas imagine 2014 with 64bit OS. Basic configurations of my computer are; i7 3820 3.60 GHz CPU, 16 GB memory (RAM), gforce GTX 680 SLI 256 bit Graphic card ( 2GPU ), 250 GB ssd. ...
2
votes
0
answers
70
views
Finding pre-processed MODIS products?
I am trying to recognize burnt areas based on some MODIS products and I just realized that I am missing a bunch pixels from the coastline masking. As you can understand that is an issue because I am ...