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.

learn more… | top users | synonyms

0
votes
0answers
20 views

Landsat Data to Map Slums in India

I am working on a project to answer the following geographic question: How much have slum areas increased in Mumbai, India, since the 1970's (or earliest data). I have downloaded LandSat imagery and ...
0
votes
1answer
187 views

Masking clouds with Fmask

I have been trying to mask clouds with the quality control band with landsat 8 imagery. The problem I continue to run into is that the quality control bands mistake tops of buildings and concrete as ...
1
vote
1answer
34 views

How do I read and modify heat map value classification on QGIS?

I am trying to create a heat map on human encroachment using the heatmap plugin of QGIS 2.2. I have no problems creating a good looking raster file using a 2 km radius but I can't find my way around ...
3
votes
2answers
68 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 ...
0
votes
0answers
28 views

QGIS vector data, graduated symbology (choropleth), discrete class bound values [duplicate]

This doesn't seem to bother anyone else, so maybe it's just me. I'm using QGIS to create a choropleth map of historic property boundaries. Since settlement occurred in pulses, I'd like to use Jenks' ...
0
votes
0answers
9 views

Creating a class based on city limits from GIS

I need to classify an entire city as one class. I have the GIS shapefile of the city limits, but am not sure how to delineate the entire area as one class based merely on the limits.
1
vote
0answers
9 views

How do I use Multispec for Landsat data?

It seems that I only can use the Clustering if I want to cluster only one band data.. If I open up more than 1 band (in one image), the cluster toolbar is disabled? optional: Is there any free ...
0
votes
0answers
20 views

When parametric classifiers fail?

In which situations are statistical assumptions (e.g. multivariate normal distribution within spectral classes) for parametric classifiers (e.g. maximum likelihood ) not valid for land-cover ...
1
vote
1answer
86 views

Interpolation and classification of soil texture data

I am trying to interpolate soil texture data on a research area. I know how to interpolate the data by making three layers for clay, sand, and silt. What I want to know is if there is anyway to ...
2
votes
1answer
150 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 ...
6
votes
2answers
209 views

What is the theory behind graduated symbols in QGIS?

QGIS offers 5 methods of classifying vector map data (quantiles, equal interval, etc). What is the theoretical base of these methods? If there are certain methods suitable for certain types of data or ...
1
vote
1answer
47 views

Setting lower and upper limits to classes in kriging interpolation, ArcGIS

I am using the kriging interpolation tool. I included two dummy values within my dataset:- an upper limit and a lower limit. I ran the tool in arc map 10.1 software. However, I want to change the ...
1
vote
0answers
29 views

Performing Maximum Likelihood Classification in R

I'm trying to perform maximum likelihood classification of landsat imagery using R, I have been searching for a package that implements it but so far I haven't found it. What is the easiest way to ...
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 ...
1
vote
0answers
16 views

Erdas Imagine Error: Performance warning: Covariance calculation requires stack processing but input layer stack isn't suitable. How to solve it?

I am collecting signatures right now and when I am adding them to the Signature Editor Erdas says: Performance warning: Covariance calculation requires stack processing but input layer stack ...
6
votes
1answer
170 views

Handling mountain shadows when classifying Landsat 8

I'm trying to classify some area in northern Mongolia using Landsat 8 satellite images from 2013. Since the recordings were made in winter, the sun is very low at the acquisition time. Therefore there ...
0
votes
1answer
66 views

Removing salt and pepper effect

In a land cover raster (categorical map) that is a product of classified satellite image, what is the best way to remove "salt and pepper" effect from the image after classification. I am not ...
3
votes
1answer
91 views

Unsupervised classification in QGIS

I was trying to learn unsupervised classification in QGIS 2.6 following the tutorial video: https://www.youtube.com/watch?v=mI80eENtWSE When trying myself, clicked Run during the process it shows the ...
1
vote
2answers
198 views

How do you remove isolated roads from a bigger network?

I'm trying to perform an OD Cost Matrix calculation on a set of points using a road network from OpenStreetMap data. The network contains lots of roads that don't connect to the rest of the network. ...
0
votes
0answers
44 views

Creating histogram/statistics/scatterplot by classification tool in ArcMap?

I'm currently working on a land cover classification with Landsat 8 imagery. I already subjected the imagery to pre-processing (atmospheric and topographic correction) and I mosaiced two images. Now I ...
0
votes
0answers
10 views

lulc unsupervised classification in envi for modis 250m data

I've got modis 250m data with NDVI,RED,BLUE,NIR,MIR bands....i have to obtain 10 classes such as Urban,Evergreen,decidious,cropland,fallowland,plantaion,water,barrenland,land with scrub,land without ...
3
votes
2answers
192 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
102 views

Correcting class codes of LiDAR files in ArcGIS

Is there any procedure to automatically correct lidar classification? My LAS Dataset has water listed as ground and buildings listed as vegetation. Just wondering if there is any option to fix this. ...
3
votes
2answers
55 views

How to compare a classified raster dataset to another polygon dataset?

I am going to perform an unsupervised classification on my dataset and will get a map as a result. The objective is to rebuild an already existing map (of different soil types) with my new dataset. ...
1
vote
1answer
40 views

Graduated values in symbology based on specific attribute in QGIS

I'm trying to solve the problem I've raised up in here.. I've rearranged the attribute table that looks like this: Important to notice is that the field "gruppo" is composed by 2 unique ...
0
votes
0answers
11 views

lulc mapping from modis surface reflectance

can i prepare LULC with 10 classes from MODIS surface reflectance level 3 data 500m resolution... if so what are the preprocessing techniques should i do on the data..i have to prepare LULC for yearly ...
0
votes
0answers
18 views

Lots of unclassified objects in eCognitions basic classification

Not for the first time I came upon the following problem in eCognition: After segmenting the objects, selecting samples for several classes and calculating their "membership function" in several ...
1
vote
1answer
58 views

unsupervised random forest classification in R

I want to compute an unsupervised random forest classification out of a raster stack in R. The raster stack represents the same extent in different spectral bands and as a result I want to obtain an ...
1
vote
0answers
19 views

How to make break values which are outside of the value range? [duplicate]

I want to compare mean temperatures for three future periods (2011-2040, 2041-2070, 2071-2100) with the measures mean temperatures of 1971-2000. My resulting shapefiles will show the difference ...
3
votes
2answers
477 views

Shapefile Conversion to ERDAS Signature editor

I'm trying to run a supervised classification for an image. I was working with it in ArcMap and created some training data. I wanted to see if I could get a better result with Erdas Imagine using the ...
1
vote
2answers
62 views

Las dataset to raster, ground points only

I'm trying to make a raster from a las dataset. I want to only use points classified as ground points but I can't figure out how to do this. What I've tried is: Create las dataset from 2 .las files ...
6
votes
3answers
297 views

How to easily identify/classify coniferous forest from one date Landsat image?

I am pretty new in remote sensing and I am trying to identify/classify coniferous forest cover from single date Landsat scene. According to my preliminary web research I have these possibilities: ...
2
votes
2answers
83 views

Counting plants in aerial images using unsupervised classification?

I am relatively new to GIS and I have the following problem: I want to extract the number of plants per row in a crop land. I have and RGB mosaic from aerial images. I think that I could do an ...
1
vote
1answer
63 views

QGIS Semi-automatic classification plugin install error on OS X 10.10: matplotlib.backends.backend_qt4agg

I have tried repeatedly to install the QGIS Semi-automatic classification plugin via both (1) Plugins > Install & Manage Plugins and (2) manually based on other comments I found here, but I ...
1
vote
1answer
257 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 ...
9
votes
2answers
236 views

Methodology for Hansen classification of Global Forest Watch?

I have just discovered amazing Hansen´s classification about forest loss and re-growth, available at http://www.globalforestwatch.org/, published in Science, 2013 as: Hansen, M. C., Potapov, P. V, ...
2
votes
1answer
63 views

Change detection between two classifications in QGIS?

I have two raster classifications. They have the same number of classes which use the same ID (each class has a unique ID). I would like to get information on the changes between classes i.e., class 2 ...
3
votes
0answers
50 views

Classification of above ground LiDAR points in ArcMap

I recently used the LAS Dataset toolbar to classify a .lasd file. The process classified the majority of points as unassigned with the rest being ground points. The study area has many tall buildings ...
0
votes
0answers
31 views

How can i perform area calculations in a raster file?

I would like to know if is possible and how can i calculate all areas or parts of it in one raster? Can i do it using the raster calculator? All help is appreciated, Best regards
1
vote
1answer
123 views

Empty signature file after i.gensig in GRASS

I'm trying to make a supervised classification in Grass 6.4.3 under Linuxmint 16. After digitizing the training areas, I transformed them from vector to raster. Then I've done the following: just in ...
0
votes
1answer
24 views

How to prevent symbology reclassification from adding 0s to the Range?

How do I prevent symbology's "Natural Breaks" from automatically changing my range to include multiple 0s after my decimals? Example: Range was originally 1 - 249. I switched to Natural Breaks and the ...
1
vote
0answers
43 views

ENVI: Postclassification, remove pixels of certain size

I did a classification over multiple Landsat imagery in ENVI 5.1, which turned out not too bad (ice and snow in Cyan in the picture below). Now I am about to do a postclassification to filter out ...
2
votes
1answer
123 views

Possible to use same signature file to classify images from different years?

I have Landsat images for the same area over 20 years (one photo per year in same season). I would like to detect changes occured in forested area like clear-cut and bark beetle outbreak over time. I ...
1
vote
1answer
56 views

How to get a total amount of cells per classification type in a raster in ArcGIS 10.1?

I did an supervised classification for for this watershed. The attribute table doesn't have the count for total number of cell for each classification. I've created a field titled 'Count' with type ...
2
votes
2answers
99 views

Classification to attribute

Using Esri Desktop Advanced 10.2.2 is it possible to create an attribute based on a classification method, i.e. Jenks? To elaborate - if you use the symbology tab in a layers properties, you can set ...
1
vote
1answer
38 views

Why does the undefined “ghost classes” arise during supervised classification in ERDAS IMAGINE?

After a supervised classification in ERDAS IMAGINE I have some undefined "ghost classes" in the attribute table. Also have a look at this youtube video at about 7:12. I'm wondering why they arise and ...
4
votes
4answers
328 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 ...
3
votes
0answers
46 views

Appropriate resolution of images for image classification?

I am attempting to perform image classification on some maps that I have in PNG format. This classification is failing due to there being too many many pixels in the training samples (I appear to be ...
2
votes
1answer
48 views

QGIS Print Composer - Display Symbols for Empty Classes?

I am working on a map of mortality rates for several racial/ethnic groups and I have created custom classes to encompass the rates instead of the QGIS classes created through its various modes. This ...
3
votes
1answer
544 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 ...