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.
1
vote
0answers
16 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
43 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 ...
0
votes
0answers
10 views
Using boolean variables in a fuzzy overlay
This question has to do with using Spatial Analyst's Fuzzy Overlay with continuous rasters and boolean rasters. The problem is that using Fuzzy Or will result in the boolean raster negating the ...
1
vote
2answers
62 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.
...
2
votes
1answer
116 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 ...
4
votes
2answers
59 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 ...
0
votes
0answers
28 views
How to snap Vector Layer projection to Raster layer projection in QGIS?
I have raster in correct projection. I used ShapeFiles, and marked objects(manually), but i found out that my vector layers have different projection, so they have different size and position. Is ...
4
votes
1answer
256 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 ...
3
votes
5answers
212 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
47 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
49 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 ...
0
votes
0answers
22 views
how separate Mixed classes
I am trying to deal with the aggregate data in Africover, I want to separate for example the mixed class – In North Kurdufan if I want the 6R from 2H/6R what is the a correct equation I have to write ...
2
votes
1answer
189 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 ...
0
votes
0answers
53 views
How to perform Neural Network Classification?
I'm using ENVI 4.8.There are some problems on parameters for Neural Network in Envi.(Envi-Classification-Supervised-Neural net)
There are 5 bands and 12 classes that i have used for my study .
The ...
2
votes
0answers
181 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
101 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
143 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
324 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
197 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
59 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
285 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
165 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
71 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
517 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
105 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
199 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
520 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
164 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
73 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
93 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
237 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
182 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 ...
2
votes
2answers
748 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 ...
4
votes
3answers
364 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 ...
0
votes
1answer
709 views
How to automatically export multiple maps with quantile symbology?
I am a relatively new ArcGIS user and I have a question about automating a tedious join/symbology classification/export operation. I have a very simple shapefile to which I join a bunch of fields. I ...
6
votes
1answer
897 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
1answer
970 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 ...
2
votes
2answers
200 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 ...
0
votes
1answer
123 views
Problem running i.gensigset in Grass. Any ideas?
It just returns ERROR: Unable to create signature file. It doesn't say why... Anyone had this before and found a solution?
11
votes
6answers
819 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, ...
3
votes
1answer
292 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 ...
7
votes
1answer
166 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
158 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 ...
3
votes
2answers
2k 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 ...
8
votes
3answers
2k 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 ...
1
vote
1answer
191 views
Creating color table file in PCI Geomatica
What is the simplest way to create a stand-alone color-table file in PCI Geomatica (PCT or STR)? I have some classified imagery with values ranging between 0-255 and I would like a way to ...
10
votes
6answers
881 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?
18
votes
9answers
2k 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?
