Questions tagged [comparison]
The act of comparing or the process of being compared.
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comparison of Historical aerial photographs to today's satellite images
I'm working on a project in which I have to compare vegetation cover changes. So we have 1950's aerial photographs which must be compared to actual satellite images. Images must be properly adapted ...
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comparing raster values over one specific transect
I have a raster with water temperature data.
I used various kinds of filters over it (smoothing, sharpening filter etc.) in various combination. I want to compare the results, to check which ...
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3
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Efficient processing of difference between input data and database
I have an input dataset whose records will be appended to an existing database. Prior to being appended, the data will go through heavy, time-intensive processing. I want to filter out records from ...
2
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How to compare a 'predicted' layer with an 'actual' layer for the same study extent?
I have developed a vector layer which predicts which polygons are more or less likely to experience coral bleaching.
I now have another vector layer with the same extent with actual coral bleaching ...
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Python vs R for analzing spatial data [closed]
I am relatively new to both the python and R programming languages, having a small amount of exposure to both. Which language has the edge when working with spatial data and when would you use R over ...
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Using IN filters in OpenLayers?
Is there a way to use IN filters (like the IN operator from SQL) in OpenLayers 2?
For example, let's say, I want a filter like this:
city = 'Paris' OR city = 'London' OR city = 'Lisbon'
In ...
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0
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98
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Tool, API of or code samples for calculating spatial similarity between Lines
I am migrating a database with a road network to an other external data provider.
We have joined our own data about roadworks, temporary speed-limits, etc., using ID and linear referencing on this ...
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1
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601
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chi-squared for two rasters in R
I am kind of new with statistics. I have two raster with categorical values and I want to get chi-square. How can I do this using R? Rasters have the same region and same resolution. Is chi-square ...
3
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Segment matching on a polyline
I have about 1000+ running routes which I can load into memory as polylines using latitude and longitude data captured from a running watch. From these polylines I would like to be able to identify ...
4
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1
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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. ...
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Road network comparisons - how to extract roads that do not completely fall within the buffer
I am trying to compare how well one road network aligns with another - I have created a buffer around the first network and would like to select only the roads from the second network that fall ...
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How to compare two feature classes on one field?
I have two feature classes: an old one and a new one that I want to compare.
Both feature classes have the same field structure and have a reference field 'ID' whose values are the same, except in ...
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how to compare geometries (contains, within) in arcpy?
I am trying to use 2 geometry objects to check if a line is within a (rather complex) polygon. The geometry check always fails, even if the line is clearly within the polygon. I use the following code:...
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2
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Python code to compare two fields in different feature layers?
I have two shapefiles which encompass 3897 features each. Corresponding shapefiles (village and watershed that flows into it) have the same ID (ws_id in one, OBJECTID in the other). Many watersheds ...
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How to compare polylines attribute from the same GRID cell in ArcGIS 10?
I need some help because I do not know how to model this issue:
I have two polyline shapefiles. They have an attribute that I need to be compared. These are roads from different sources. So, I have ...
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3
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Calculation based on features in shapefile
I hope I get the terminilogy right! Correct me if I mess something up.
I need to perform some calculations for a scoring system for different habitat types.
The Problem is that I have two different ...
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Comparing routes using code? [closed]
I am looking for a way to compare routes of two or more persons to be taken by car.
Person 1 has a starting point A1 and a destination point A2.
Person 2 has a starting point B1 and a destination ...
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1
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How to use "this" Levenshtein Python code into ArcGIS 10
I need some help with this:
First of all, I wanted to "Compare strings from two fields", and asking before at gis.stackexchange, in this post someone help me with this topic, referring me to a Python ...
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1
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How to compare string fields in the same table with ArcGIS 10
I don't know exactly if there is a tool for this or a maybe a python script could be more suitable.
I want to compare string elements from a field (POI_NAME) with another string element in another ...
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6
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Looking for simple software to compare two Landsat Images
At uni I used ERDAS imagine to view two rasters at the same time and it had various viewers for comparing them. I'm looking for something that has a slider so that I can see the differences between ...
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Bentley Microstation in comparison to ESRI ArcMap : Filetypes and Capabilities
I'm curious if there is a side-by-side comparison of Bentley's Microstation v8i (Select series 3) with ESRI's ArcMap 10.1 showing capabilities and filetype acceptance.
I have heard some conversations ...
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What is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator?
Stemming from my other question: When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?, what is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator?
It ...
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1
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When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?
I have a couple of featureclasses in a 10.2 geodatabase/PostgreSQL 9.2.2 database and I've been struggling with the FeatureCompare tool--it is telling me geometries are different on some features ...
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resampled thematic map accuracy
I've generated a map of ecoregions based on some environmental data using a semi-supervised classification where I combined a statistical clustering with random forests to generate my map.
I created ...
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How successful are current metadata implementations in achieving its objectives
Metadata infrastructure is well established as an essential practice within the GIS community. Quoting from the FGDC:
Metadata helps people who use geospatial data find the data they need and ...
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440
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Different models, different contours: are they comparable?
I will get contour lines of electromagnetic field strength around power lines. The contours will be calculated by different agencies using different models. We need to check whether the resulting ...
2
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1
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689
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Easiest way to find spatial differences between Polyline shapefiles
I run into this problem a lot. I have two polyline's and I need to test for Spatial differences in them. Usually I use Erase and I have my answer, but on this PC I now only have access to ArcGIS Basic ...
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Comparing choropleth maps statistically
I have several sets of choropleth maps showing ranges of poverty by census tract, each using a different poverty measure. All of the maps use the same categorical ranges to define poverty status.
The ...
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7
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Geocoding APIs comparison
Is there a good updated source for comparing existing Geocoding APIs (i.e. Google, MapQuest) and their features?
I'm really interested in their language support as well. For example, Google has ...
0
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1
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Comparing ShapeFile Data in C# [closed]
I have made a List containing all the original data (.shp files), and I have another List containing the modified data. I basically want to check all the modified file data against the original... So ...
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3
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Comparing differences in two polygon shapefiles using ArcGIS Desktop? [duplicate]
I am a new user to Arcmap 10. I've been trying to figure out how to compare two polygon shapefiles. I need to figure out what the difference is from 2007 - 2013 (increase/decrease) in a couple of ...
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1
answer
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Compare two Digital Elevation Model (DEM)
I would like to know what's the best method(s) to compare two DEMs without using any GUI soft like QGIS or ArcGIS.
I'd like to do it in Python or C++, with GDAL or other similar lib.
Does calculating ...
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1
answer
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Comparison of three contour lines
I am looking for a way to spatially quantify the difference between three contour line shapefiles. More specifically, I have two elevation rasters which I intend to create contour lines from, but ...
7
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1
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How to efficiently (programmatically) determine whether two datasets have / don't have identical content? [closed]
Given:
a geodatabase A that contains 100 datasets named a1 .. a100
a geodatabase B that contains 100 datasets named b1 .. b100
I want to programmatically (*) determine for each dataset pair (ai, bi) ...
9
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2
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Tools to compare unversioned copies of geospatial data [closed]
My office has about 100 GB of geospatial data of varying forms (imagery, feature classes in geodatabases, LIDAR, tables, etc) that have gone somewhat unmanaged for the decade during which they were ...
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2
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I am looking for a list of mapping libraries? [closed]
I am looking for the top APIs that I can use to display maps from a number of map servers/sources. (like openlayers and openscales). So are there any other popular APIs for other languages than ...
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2
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Does MySQL only support bounding boxes calculations instead of the real polygon geometry?
Within our company we are deciding which DBMS we will use to store spatial data. IT wants MySQL with the Spatial extension because there is already knowledge about handling MySQL DB. We are doing ...
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1
answer
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What is Market share for open source web-GIS systems? [closed]
I would like to know the market share of 3 web-GIS systems, deegree, GeoServer, Geomajas).
Which one is more popular?
Are there any evaluations regarding the market share of open source web-GIS ...
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0
answers
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Can Quantum GIS replace Proprietary GIS? [closed]
I’m an MSc GIS student in the final year of my studies. I’m researching for my dissertation project which is entitled ‘Can Quantum GIS replace Proprietary GIS in large organisations?’
I’m primarily ...
2
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0
answers
467
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ArcGIS/arcpy: Geometry object comparison methods not working. Do they take z values into account?
I have an arcpy script that makes calculations based on an input PolygonZ feature class. What I need to do in several places in the script is test whether a point falls within a polygon in 2D. In ...
2
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1
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Compare workspace schemas in Modelbuilder
My model has two model parameters:
A file gdb workspace or sde workspace containing the data
An empty "template" file gdb
As the very first process in my model, I want to check if the schema of the ...
6
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1
answer
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How to compare 2000 Census block group data with 2010 block group data?
I want to calculate the percent change for median household income in Los Angeles at the block group level from 2000 to 2010. Someone told me I have to reaggregate 2000 block data to 2010 block group ...
5
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3
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725
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In what data format should I export a (lat,long,alt) or (x,y,z) grid to be compatible with the largest number of GIS software?
I am new to GIS and developing an application that generates a 3D grid with (latitude, longitude, elevation) or (x, y, z) metric triplets, and I would like to add an exporting feature that ensures ...
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1
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Looking for a trajectory similarity measure
For my final academic work I have developed a compression algorithm for GPS trajectories. I can estimate the quality of the spatio-temporal compression by computing the syncronized euclidean distance (...
8
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5
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Comparison of Open Source Desktop GIS Packages
I'm curious as to what comparisons are out there between different Open Source Desktop GIS software packages. I'm aware that there has been a QGIS and gvSIG comparison on this site but I am looking ...
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0
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Manifold 'Link drawing to query' - can I do this in QGIS?
Manifold GIS allows the creation of dynamic drawings linked to queries.
Unfortunately I do not have access to Manifold as my employer refuses to pay for it, so am currently investigating alternatives....
6
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4
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Basic .NET mapping components?
Which .NET mapping components are currently available? Focus is on desktop use and fairly basic mapping of SHP files (thematics etc.), not the more advanced GIS functionality (reprojections, clipping, ...
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2
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What are the pros and cons of using the ArcGIS Viewer for Flex vs. creating your own GIS application vs creating your own framework?
Simple question, but perhaps hard to answer. I have broken the title question into three distinct questions in order to clearly identify what we are considering for options each time we build an GIS ...
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2
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PostGIS feature compare function?
I would like to be able to compare features in Layer 1 (source) to features in Layer 2 (updates to source) in order to see if any of the features geometry and/or attributes have changed. I would also ...
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4
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Comparing 2 vector files
I'm looking for a tool which compares two vector files (eg shapefiles). Eg 2 versions of a river network.
Quite a lot of the records are equal, but some are different. A possible output would be eg a ...