The process of sorting or arranging entities into groups or categories; on a map, the process of representing members of a group by the same symbol, usually defined in a legend.

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19
votes
9answers
3k 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?
13
votes
6answers
2k views

Freeware alternatives to eCognition?

Does anyone know any good freeware alternatives to eCognition? I need to do image segmentation and classification. I tryed the ecognition trial and it was really good. I'm doing the job with SPRING, ...
10
votes
3answers
3k 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 ...
10
votes
6answers
975 views

What is this “brown spot” in Google maps?

I was in Google maps today and noticed near Baltimore, US where the river is, there's a huge brown spot. Is this due to all of the waste? If so, will this keep going all the way into the ocean?
8
votes
1answer
1k views

Open software tool or QGIS plug-in to make land cover classification

Is there any tool or plugin for QGIS/GRASS to make an automatic land cover classification from satellite imagery --- based on CLC nomenclature for example? Of course, it will not be 100% sure but it ...
7
votes
2answers
121 views

How to classify agriculture employment data?

I have employment data which are huge - about 500 data for each category, like agriculture field, fishing field etc. Now I want to categorise this data in to 7 ranges. Suppose <50=1, >50-100=2, ...
7
votes
1answer
2k views

Permanently Change ArcMap's “Maximum Sample Size” Setting?

I've lately been working on feature classes with a huge number of polygons (e.g. all of the Census blocks within the Chicago metro area). I've been needing to symbolize them by quantities a fair ...
7
votes
1answer
180 views

View data of a particular year in Google Earth

For my region in India, Google Earth tiles belong to different years, 2003 - 2010. I don't mean GE's historical view feature but the imagery updates for different areas my region. I classify Landsat ...
6
votes
3answers
268 views

Is it possible to automate the detection of clearcut areas in optical satellite imagery?

Given optical satellite or aerial imagery of a resolution similar to the image below, is it possible to accurately detect clearcut areas? Is their research or documentation that supports a specific ...
6
votes
3answers
173 views

Classifying small structure in water using IR band

I was wondering how to identify small structures (eg. beacons) in a water body. I have worked with RGB images and its almost impossible to classify waterbodies in these images. How does IR band help ...
6
votes
3answers
173 views

Best practices for identifying training sites

Prior to image classification, collection of training sites and obtaining a signature file is the most critical step. Field visits with a reliable GPS Unit is usually the first step followed by ...
6
votes
1answer
550 views

How to perform unsupervised classification of LANDSAT time series using Grass?

I'm using GRASS to perform an unsupervised classification on a time series of LANDSAT images (monthly temporal res, over 30 years), in order to compare land cover change in a particular area. I'm ...
6
votes
3answers
2k views

Best 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 ...
6
votes
0answers
344 views

Land Classification with Spectral Python (SPy) [closed]

Does anyone have experience working with the Spectral Python module for land classification? The following k-means clustering example takes an iterative approach to classification through pixel ...
5
votes
1answer
186 views

ArcMap Natural Breaks Classification

I realize that ESRI is calling their implementation of Fisher-Jenks proprietary. Given the performance with mid-sized datasets, either a significant optimization or a sampling method are being ...
5
votes
2answers
189 views

How to know what spectrum image layers are in eCognition?

I'm learning to use eCognition (8.1) and my teacher has provided me with some example tif files to segment and classify. The tif files have multiple layers, each of which are supposed to represent a ...
5
votes
1answer
108 views

How to design class breaks for a time series of choropleth maps?

I'm working with a time series of choropleth maps showing the same indicator for the same administrative boundaries, but spanning period of nine years. What would be the most appropriate strategy of ...
4
votes
5answers
971 views

Which methods are most suited to classifying urban areas from Landsat imagery?

I am trying to use Landsat data to map urban extents over time. I need to perform a classification into built up / non built up areas. I am new to image classification. I have access to the following ...
4
votes
2answers
3k views

Reclass for vector data in ArcGIS

I've got a vector dataset (in fact, OS MasterMap data) and I want to set the value of a certain field based on the value of another field. For example: Field1 Field2 Building 20 Grass ...
4
votes
3answers
561 views

Remote sensing: How to define landuse from remote sensing data?

I am trying to research ways into obtaining landuse data for a project which calculates the visual impacts of wind parks. I have a DEM and DOPs for a relatively large region (5000km²), but I have no ...
4
votes
1answer
1k views

How to train a signature file for supervised classification in ArcGIS 9.3

I wanna do supervised classification in ArcGIS 9.3. I have a 321RGB composite of a pretty good quality which I want to use for supervised classification. How can I create signature file which contains ...
4
votes
1answer
113 views

How do I manually classify graduated data in QGIS?

Is there any way to manually classify Graduated Data in Qgis. In ArcGIS I always used to apply first the natural breaks method to find adequate group sizes for good visual interpretation. Afterwards I ...
4
votes
1answer
238 views

Creating management zones in NDVI ortho maps with contour like lines

This question is hard to explain so if you have a possible answer I would love to hear it. I work in the precision agriculture business which heavily relies on NDVI calculations but need to create ...
3
votes
1answer
44 views

What does Error 000885: Input Signature file does not have file extension indicate?

I can't run a Maximum Likelihood Classification because an Error 000885 says my input signature file does not have a file extension but it actually does as you can see in the picture. What am I ...
3
votes
1answer
298 views

Cloud and Snow Differentiation

I am doing unsupervised classification of a mountaneous terrain and I have used 500 classes to classify the land use. In my result, cloud and the snow are categorized in the same class. How do I ...
3
votes
1answer
44 views

How do I classify number values in Python to assign it to a group?

I have calculated the number of points that exists for a SqMi area and am trying now to assign it to a certain group based on where it falls in the classification. Does anyone know a tool that I can ...
3
votes
2answers
234 views

calculate coastline at risk

I have an idea of what I want to do but I don't know yet what tools will bring me there. I have administrative boundaries in one layer and coastline in another layer. The coastline is categorized in ...
3
votes
1answer
257 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 ...
3
votes
1answer
94 views

Spatial Classification

I am not sure what to call my problem. From this image, I have a set of classified polygons (colored). I would like a way to classify the white polygons in the image. I don’t have any attributes to ...
3
votes
1answer
259 views

How to build a confusion matrix for image classification using SAGA or QGIS?

I did a supervised classification of a Landsat image subset using my training data polygons. I used SAGA GIS for that and everything worked out fine. Now I am stuck since I have no clue how to ...
3
votes
1answer
47 views

Sample classification datasets?

I was looking for some publicly available ground data classification datasets, specifically, locations in e.g. latitude/longitude with a description of the land cover/land use, and a reference e.g. ...
3
votes
1answer
355 views

Standard Colors for Landcover Maps

I have classified Landsat images into five classes - A variety of Palm, Water bodies, built-up/open area, other vegetation and miscellaneous. I used GRASS GIS for the process and the final classified ...
3
votes
1answer
147 views

Convex Hull in SAGA Gis

How does one go about creating a convex hull from a set of points in SAGA GIS? I read that this is possible in QGIS, but I prefer SAGA and would like to see if it is possible. Furthermore, if it is ...
3
votes
0answers
320 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 ...
2
votes
2answers
229 views

LANDSAT Image classification and open source solution(s)

I have some experience with ERDAS IMAGINE in doing some supervised/unsupervised LANDSAT imagery classifications and now find myself in the position of needing to do the same but without the access to ...
2
votes
2answers
990 views

Land use land cover change post- classification in ArcGIS for cross- tabulation

Please some one help me first I have finished the image classification process in another software package but many literary recommend Arc GIS package to process post-classification which means from ...
2
votes
1answer
793 views

Image classification random forest [duplicate]

I am a newbie in R. I want to classify images using random forest in R. I am trying to learn the codes. But in the mean time, is there a push button (like a gui) in R that can be used for ...
2
votes
2answers
223 views

How to remove roads from dataset

I've got a shape file that I loaded into PostGIS that has both road and parcel multipolygons and I need to remove the roads. I tried loading the shp file in qgis and it loads them both as a single ...
2
votes
1answer
43 views

Correcting Classification for LIDAR - ArcGIS

Is there any procedure to automatically correct lidar classification? My LAS Dataset has water listed as ground and buildings listed as vegetation etc... Just wondering if there is any option to fix ...
2
votes
2answers
1k views

How to vectorize a Raster-Classification? (qgis, grass)

I classified my raster-DHM into elevation levels using colormap. Its not a "real" classification, just a colormap. So I cant vectorize the classes to get polygones for every class. Whats the best ...
2
votes
0answers
32 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 ...
2
votes
0answers
34 views

differentiating stone houses from barren rock in ArcGIS 9.3

I'm working in ArcGIS 9.3 trying to differentiate stone houses (often red brick roofs) from barren rock in a typical Mediterranean karst region via remote sensing. I have been using Landsat imagery. I ...
2
votes
0answers
76 views

quantile calculation in qgis

I have a simple question about the graduated classification in qgis (version 2.0.1). I can choose between several statistical methods to classify my data (standard deviation, quantile, natural ...
2
votes
0answers
126 views

Image classification for a study site falling over two adjacent Landsat 8 scenes (qGIS or ArcGIS)

This question concerns work-flow rather than specific methodological problems. I will be using GRASS to classify Landsat 8 images to create a vegetation map for a study site that happens to fall over ...
2
votes
0answers
72 views

Flood extent extraction from satellite images

How i can extract the floodwater from satellite images? Is the image classification method accurate for moderate-resolution satellite (Terra/Aqua MODIS)? Or is there a more accurate methods? Thanks.
2
votes
1answer
58 views

From where I can get 4-band satellite imagery of Sweden?

I'm looking for good quality, fine resolution 4-band satellite photos of Sweden for academic use (and I'm willing to pay for it). What I'm after is as detailed as possible photos of certain part of ...
2
votes
0answers
348 views

ISODATA unsupervised classification in ArcMap 10.1

I’m doing a project on landsat 5 images. I’ve composited the images into 1 raster, and I want to classify the raster with ISODATA Unsupervised Classification. How do I calculate the best number of ...
2
votes
2answers
1k views

How to classify/style rasters correctly?

I am using a GeoTiff raster data and trying to classify it. I was wondering what are the techniques that I can use in QGIS to do this? The raster I have looks like but I tried the reclassify tool ...
1
vote
1answer
68 views

the difference between pattern recognition and image classification in remote sensing? [closed]

Does anyone know the difference between pattern recognition and image classification?
1
vote
1answer
22 views

Creating training areas for parametric classifcation

I am creating a signature file for a supervised classification for a subset of a LANDSAT image. I know what classes I would like to create, and have identified ideal areas for training. However, I am ...