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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2
votes
1answer
110 views

More presentable style class range values, faster

This is as much feature suggestion as it is question: Is there a better way to generate attractive/presentable style class ranges? Currently I have 5 similar datasets. Lets say the values for the ...
0
votes
0answers
127 views

OBIA following connected components segmentation in Monteverdi2

New to Monteverdi2 and OTB. I just finished a connected components segmentation using the Segmentation module and the large-scale vector output mode for large datasets. How can I filter the output ...
3
votes
2answers
198 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 ...
2
votes
0answers
40 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 ...
3
votes
2answers
101 views

How to change class break schemes in QGIS to eliminate overlap

When using Graduated Symbology in QGIS, by default the bounds seem to be overlapping. For example, class 1 shows 0-100.000; class 2 shows 100.000-200.000; class 3 shows 200.000-300.000 where it ...
2
votes
2answers
517 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 ...
0
votes
0answers
36 views

Method of extracting the intersecting areas of multiple overlapping polygons (5) and classifying intersects based on spatially joined points

I have concave hulls surrounding clusters of data points which has led me to a lot of overlap and fuzzy boundaries. I am attempting to intersect the overlapping areas but have a minimum of 5 different ...
5
votes
1answer
430 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 ...
4
votes
1answer
253 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 ...
0
votes
1answer
93 views

Which Landsat version is appropriate to imply a supervised classification with GRASS GIS?

I need to imply a supervised classification with GRASS GIS to find build-up areas. I want to avoid Landsat 7 images due to SLC problem. Can I use images of Landsat 8 or it's better to use images ...
3
votes
1answer
589 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
60 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. ...
2
votes
1answer
168 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 ...
1
vote
2answers
126 views

how create a specific sub-study area in ArcGIS 10.1 - difficulties with classification

My study area is quite large (sometimes spanning across a few grid squares) and when I am running a viewshed analysis or calculating slope or euclidean distance it calculates for the entire region. ...
1
vote
1answer
90 views

Exporting classnames using Monteverdi

i managed to get my rgb-Image classified with Monteverdi. I discribed 8 classes with different classnames. For my work i dont need the rgb-values, i just need the classnames. Is there any way to ...
2
votes
0answers
209 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
91 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.
1
vote
0answers
170 views

where to perform principal components analysis and tasseled cap transformation [on hold]

I want to perform a principal components analysis (pca) and a tasseled cap transformation (tasscap) for a classification.Should i perform pca and tasscap on the original bands of my image or on the ...
1
vote
1answer
196 views

ArcGIS raster data - Group statistics for classification

I'm trying to figure out how to classify a group of rasters. These can't be joined as they have overlaps which must be kept. I was wondering whether there's a way of obtaining grouped statistics - eg ...
1
vote
1answer
143 views

How to do separability analysis in eCognition?

Can I use eCognition to check which bands are more helpful to separate individual classes and to get output result? If so, how can I do this?
2
votes
1answer
1k views

Convert 32 bit image to 8 bit image in QGIS

I want to convert my images from 32 bits to 8 bits. I'm using otb to calculate texture and the raster output is on 8 bits, I'm going to use this information as a layer stack for my multispectral image ...
2
votes
1answer
71 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 ...
4
votes
1answer
343 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 ...
1
vote
3answers
431 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. ...
3
votes
1answer
337 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 ...
5
votes
2answers
334 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 ...
9
votes
5answers
6k 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 ...
5
votes
5answers
1k 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 ...
0
votes
1answer
180 views

How do I classify or spot a pixel, based on a specific reflectance values of the six Landsat Bands using Erdas?

I have converted the DN values to the reflectance of a Landsat image to classify the rice field by its stages. To specify the reflectance values of each stages, I have sampled the reflectance values ...
5
votes
1answer
149 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 ...
2
votes
1answer
1k 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
0answers
495 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 ...
7
votes
2answers
133 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, ...
6
votes
3answers
192 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 ...
2
votes
2answers
1k 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 ...
6
votes
3answers
359 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 ...
0
votes
2answers
83 views

Common class range for different attributes in a same polygon shapefile

I have a polygon shapefile which has population attributes pop90,pop91 and so on for 10 years. They have different minimum and maximum value for each of the years. Now I need to do classification for ...
6
votes
1answer
807 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 ...
3
votes
0answers
433 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 ...
1
vote
0answers
131 views

Segmentation Violation in ArcView 3.1 while performing UpdateLegend?

I am loading a ".avl" legend file into ArcView 3.1 and I am plagued with a recurring Segmentation Violation Error when I execute the updatelegend command in the theme. It looks like the legend file ...
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 ...
3
votes
1answer
181 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 ...
1
vote
1answer
973 views

How to merge different classes/clusters in one single raster in arcgis 9.3?

I've created a signature file with 8 clusters and performed an unsupervised classification. Later I have grouped values (spatial) classes together to form 4 classes I needed (in symbology) but that ...
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 ...
3
votes
2answers
299 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 ...
1
vote
0answers
96 views

From classified image to topology in ArcInfo

I have some coastal 4 band imagery that I have classified to designate land, water, and undetermined. I want to convert this to polygons with topology, and significantly simplify the polygons. If I ...
1
vote
1answer
168 views

Symbology for specific values

I want to apply a symbology scheme for the final layer of my model. Rules are - All negative - Symbol A 0 - Symbol B All positive symbol C unknown - symbol D I am not sure how I can define these ...
6
votes
0answers
453 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 ...
3
votes
1answer
425 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
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 ...