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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12
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3answers
5k 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 ...
15
votes
4answers
8k views

free GIS software that can orthorectify?

Would someone care to recommend a free and/or open source GIS application that can orthorectify map images?
21
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5answers
7k 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. ...
22
votes
12answers
15k views

What is the best 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 ...
4
votes
5answers
2k 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 ...
4
votes
1answer
3k views

Open Source Alternatives to ERDAS IMAGINE ATCOR?

I have been using ERDAS IMAGINE's ATCOR extension for ATmospheric CORrection of ASTER imagery. What opensource options exist for atmospheric correction of ASTER Level 1B products? I'm primarily ...
26
votes
7answers
4k 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 ...
15
votes
3answers
3k views

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, ...
5
votes
2answers
2k views

Open source solutions for Landsat-8 mosaicing and correction?

I am familiar with the major commercial remote sensing packages (ENVI, IDRISI ERDAS, etc), but I haven't previously had the opportunity to utilize open-source solutions. I have a several new Landsat-...
12
votes
5answers
13k 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 ...
9
votes
1answer
5k 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 ...
8
votes
2answers
3k 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.
2
votes
1answer
2k views

Reprojected MODIS NDVI has range from -32768 to 32767, expected -1 to 1

I'm new to StackExchange and to remote sensing. I am working with MOD13Q1 250m 16-day MVCs. My goal is to use NDVI time-series to classify cropping pattern and crop type, then link this data to ...
4
votes
1answer
575 views

How can I parse modis MOD13Q1 quality layers in R?

I'd like to parse MOD13Q1 VI quality layers in R. My original code must have been incorrect, because it gave lots of "deep ocean" flags in the middle of Brazil. After the changes suggested by Mikkel,...
18
votes
9answers
6k 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?
8
votes
2answers
1k 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 ...
3
votes
1answer
619 views

Random-Forest Classification of 10cm Imagery for species-distribution in R (no point-shapes)

I'm actually trying to classify 10cm-resolution images with the RF-package. I do this to separate some species in the forest, seen on my images. While I was searching for an answer, I found the ...
4
votes
1answer
584 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 ...
4
votes
1answer
465 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 ...
2
votes
1answer
137 views

Incorporating terrain data to predict canopy cover using randomForest in R

This is a subjective question. Thank you bearing with me. I have a 5.8 m resolution satellite image (LISS IV by IRS-P6, in bands 4, 3 and 2) of a densely forested region in the Eastern Himalayas. My ...
4
votes
2answers
2k views

Calculating Net Primary Production (NPP)?

When I calculate Net primary production (NPP) for a local scale, what kind of software should I use? I always use ENVI, ERDAS IMAGINE, ArcGIS for Desktop and IDRISI. Is it possible to use these ...
4
votes
2answers
203 views

Why does the resolution decrease with increasing incidence angle in the Sentinel-1 SAR sattelite

On this link (Sentinel1 webpage for a SLC product), the resolution is written as a range from the highest corresponding to low incidence angle, to the lowest resolution corresponding to high incidence ...
3
votes
5answers
3k views

Fix Landsat 7 SLC-off in ENVI?

I have a couple of Landsat 7 images and they all have striping as a result of the SLC failure. Does anyone have any suggestions as to how to destripe the image using ENVI? I plan to use these images ...
4
votes
1answer
772 views

Estimating Landsat 7 azimuth (heading)

I am trying to understand if the Landsat 7 satellite ETM+ orbit has any significant azimuth or if it could be assumed as 0° (as it is not a pointable sensor). I searched in the web but could not find ...
3
votes
2answers
152 views

Is SRTM 3 second arc free of non-terrain features?

I made an elevation map of my study area in Macapa, Brazil. But the region has the average elevation lesser than 30 m as I can see from my map derived from SRTM 3 second arc. According to my ...
2
votes
2answers
2k views

Converting *.tif file into headerless (flat) binary file?

I am using NDVI files (value range -1 to +1) created from Landsat CDR images to produce a timeseries in TIMESAT software. My .tif file has following characteristics. File type TIFF,Data Type ...
1
vote
2answers
791 views

LANDSAT 8 i.landsat.toar error GRASS 7

I am a bit new to GRASS, but I have managed to get a lot of good work done thus far. However, the following error is really throwing me off, because I can't find any help anywhere for it. I am using ...
1
vote
2answers
326 views

How to find the minimum pixel value within a region of interest?

I am working on a Python script for dark object subtraction, a radiometric correction method for remotely sensed data.To accomplish this, I need to find the minimum band pixel value of a waterbody ...
14
votes
3answers
799 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 ...
12
votes
5answers
4k 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 ...
13
votes
9answers
1k 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 ...
6
votes
2answers
7k views

Landsat in ArcGIS

I need to learn how to download, import and compose Landsat 8 in ArcGIS for natural colors (preferably in a GEOTIFF format). I have tried on my own but it seems that I am doing something wrong... can ...
5
votes
2answers
2k views

Are there Python packages for Landsat 8 processing?

While there are a number of python projects for MODIS acquisition and processing (pyModis and get_modis), I have yet to encounter a toolset for automating Landsat 8 processing in Python. There's ...
5
votes
2answers
3k views

Moisture Interpretation from Landsat Images

I am working on a "land suitability for crop" project. Can anyone let me know how to get any type of information which can be related to moisture index of soil? I have Landsat 5 data with band 3 and ...
15
votes
3answers
1k 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 ...
0
votes
2answers
3k views

how i calculate land surface temperature using landsat 8 in Envi 5.1

I am doing research about land surface temperature using Landsat 8 image. However, I have a problem with them. I have read document from Landsat.org, but i can not do it in Envi. Could you help me ...
4
votes
2answers
166 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): ...
4
votes
2answers
142 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 ...
4
votes
6answers
3k views

shadow simulation from buildings [duplicate]

is it possible to use hillshade function in ArcMap to calculate shadow areas of buildings or simulate shadows of buildings, using DSM of the buildings and the sun angle and azimuth?
3
votes
2answers
2k views

Figuring out map scale when you know the spatial resolution of a Satellite Image?

I'm interested in figuring out how map scale and satellite pixel size (spatial resolution) are related. For example the TM or ETM+ has roughly 30m ground resolution, then, what could be the finest ...
3
votes
3answers
767 views

How to extract surface from air photo avoiding trees and buildings?

I am working with Drone air images. These are geotiff images and clearly portray trees and buildings. I need to first classify the image according to land cover distribution, then need to remove the ...
3
votes
1answer
399 views

Is atmospheric correction necessary when working with multi-spectral indexes?

When you are working with Landsat Level 1 data and calculate indexes, e.g. NDVI, NDBI, SAVI ..., do you calculate them using raw data (pixel DN value), or atmospherically corrected data (surface ...
3
votes
3answers
3k views

Where to download 4 band NAIP imagery?

I seem to recall USGS Earthexplorer providing current and historic 4 band NAIP imagery over the last few years. It appears that these data have been migrated to the National Map. However, the ...
9
votes
1answer
532 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 ...
6
votes
2answers
1k views

Transform SPOT5 images to natural color images

We're currently using PixelSense to convert raw SPOT5 images to natural color ones for display and printing. Do you know a good algorithm to perform the same task as we want to ingest raw images in an ...
4
votes
2answers
943 views

Best Landsat-5 TM band combination for detecting fire scars

I am looking for the best band combination with Landsat 5 imagery to detect fire scars.
3
votes
0answers
487 views

Single Tree detection

I was wondering how I could extract "crown area" of single trees in a forest from a high-resolution image with only 3 band (RGB) in ArcMap. ( No NIR to use NDVI as any threshold). I need a fast easy-...
3
votes
0answers
53 views

How to classify difference surfaces having almost similar Reflectance responses?

I am using ENVI 5.3 to classify a Region of Interest clipped from Landsat 8 OLI. I have already performed calibration of my DNs by transforming it into Radiance and derived Reflectance image using ...
2
votes
3answers
2k views

Failed to create signature file

I need some help, because I've no clue how solve this issue the exercise that I'm trying to perform. The point where I'm stuck is 4. "Create signature file as LandsatCompS.sgs". I've done what it ...
2
votes
1answer
340 views

I need some more information on ASTER for time series analysis

See my previous post on ASTER I have a question about that I am not sure about. So, if I wanted to analyze 10 years or so, do I need to download each ASTER file for each year (e.g. 2003 ASTER, 2004 ...