Questions tagged [comparison]
The act of comparing or the process of being compared.
100
questions
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Side-by-side Leaflet map - How to add an array of layers to show on one side?
I want to create a side-by-side leaflet map and I use the resources available on github (https://github.com/digidem/leaflet-side-by-side). I have downloaded the code locally and I have created a map ...
3
votes
1
answer
72
views
Find all geometries in one table that do not exist in another
Using PostgreSQL and PostGIS, I have two tables of polygons, and I need to know which of the records in table p1 do not exist in table p2. I do not have additional information available (e.g. ids) - ...
0
votes
0
answers
30
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Validating raster soil map through independent point set of soil attributes
If I have a raster map of pH, and a point (vector) dataset of map independent pH measurements, then how can I validate the accuracy of the existing raster with these extra measurements?
I don't have ...
-1
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2
answers
87
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Comparing similar words in two different columns [closed]
i have list of different categories in same dataset in two different coulumns
There are some similar words in the two columns. So by comparing the two columns the maximum matched wordings should be ...
3
votes
1
answer
743
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How do you compare all fields in multiple feature classes?
I have two features classes that should have the exact same fields. There are over 500 fields, I am looking for a code that will compare the fields and identify if there are fields in either feature ...
3
votes
2
answers
242
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Comparing arrays in QGIS
I want to compare two arrays and if they match exactly a specific value should be assigned to a field. For instance, if the values in "sumEHZ" are [A,B] or [B,C] the lower value should be ...
2
votes
0
answers
92
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Comparing Heatmaps over time
We have a huge dataset of mobile users (tourists) and want to see how the density in a city has changed (from one spot to another) before during Covid. Of course we can create a heatmap for different ...
0
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1
answer
162
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Gettting data from georeferenced PNG QGIS
I'm working on a predictive system and was able to locate a PNG from another researcher showing a heat map of Oklahoma. I was able to georeference the PNG and bring it into QGIS 3.22. What I need to ...
0
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1
answer
748
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Air temperature chart using ERA5 dataset in Google Earth Engine [closed]
I used this code to map 2-meter temperature over Italy from 2000-2020 using ERA5 dataset in GEE.
https://code.earthengine.google.com/6dc6f44e827b9e033d2c2227aa2363b1
I used Mean reducer to show the ...
3
votes
0
answers
43
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Empirical Line Method (ELM) in ArcGIS Pro [closed]
My images from 2017, 2018, 2019 and 2020 from the same area, recorded in the same time of the year, all look different regarding colour brightness, likely caused by atmospheric circumstances. As I ...
1
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0
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230
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Statistical comparison between two maps with aggregated average observations and average estimates from a model on a 1 x 1 km² grid
I've been searching for methods for the past two days, but I couldn't find something usefull, so I hope someone could help me out:
I've got two datasets in python containing PM2.5 values:
Dataset ...
8
votes
1
answer
256
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Points disappearing after pasting symbology from another layer in QGIS
I am planning to plot some graduated points, based on their value, while also keeping the scale the same for different parameters. Naturally, I imported the CSV file that included the points. Upon ...
0
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0
answers
119
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Statistical difference in DEM-height compared to a specific point(feature)
Recently I've been struggling when trying to compare surrounding points of a DEM to a specific one (a feature in my case. A castle to be precise). I want to find out how steep a slope in an area ...
2
votes
1
answer
5k
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Compare two shapefiles by location and attribute in QGIS
I am looking for a way to compare two shape layers automatically. We have two files that represent two different states of our project and thus contain similar data in the same format (e.g. both point ...
0
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1
answer
1k
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Comparing two rasters using ArcGIS Raster Calculator
When I tried to compare two rasters in Arcgis by using Raster Calculator, the resulting raster includes positive and negative values.
How can I interpret these values?
What does the mean of the ...
0
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398
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Comparing two point clouds, one in WGS84 and the other in ECEF
I'm really a newbie and this task seems over my head. Suppose you have one cloud from LiDAR (a LAS file) with coordinates in WGS84 and another cloud, obtained from structure-from-motion, in ECEF. They ...
3
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1
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542
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LIKE-comparison with wildcard between value from table and value from atlas_feature for filtering attribute table using QGIS
I am trying to filter an attribute table in QGIS Print Composer based on the current active atlas feature:
I have a table with an "id" column with and some records that have these values in ...
5
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1
answer
742
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Satellite imagery comparison
Earlier in my searches I had come across this website which provided a fast switchback between all the map providers (Apple Maps, Google, Bing, OSM) where you had the chance to compare the satellite ...
1
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2
answers
162
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Comparing several values within each cell of a DEM
I am working with a DEM and got a GPS line of my working area.
I converted the GPS line into single measurement points. Now I want to compare each of these GPS points with the corresponding elevation ...
4
votes
1
answer
244
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QGIS: Select point(s) in other layer with similar datetime value from selection
For the interpretation of bird observations, I need to identify the position on a GPS-track (gpx-files), from which the position of a bird observation (other gpx-waypoint layer) was recorded.
The ...
4
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0
answers
206
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QGIS vs gvSIG: Update for 2019 [duplicate]
There were two posts from back in 2011 about the advantages of gvSIG and comparing QGIS and gvSIG. It's been 8 years since and I'm wondering if there might be an update since gvSIG and QGIS (at time ...
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0
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93
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Comparing Multiple Shapefiles
I have 4 shapefiles that I need to compare spatially, to highlight inconsistencies between them in ArcGIS. I have used the Feature Compare tool so far, but I'm looking for a faster way to compare the ...
1
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1
answer
31
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Selecting Different points in 2 different layers
I'd like to make an analysis on points.
I've 2 layers they have house numbers as an attribute. What i'd like to do is compare these 2 layers and select the different ones.
Geometrically there are ...
1
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0
answers
34
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Merge partial (or entire) geographical paths [closed]
I have data of a vehicle route and some data already inserted in the system. I have to find the parts of the route that are already presents in the system in order to avoid duplicate the info.
The ...
1
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0
answers
77
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Comparing yearly changes in TaxLot land use in NYC (mapPLUTO) - tax lots change through time
I am trying to build a database for NYC in which, for specific boroughs of the city, I track changes per tax lot unit in terms of land use and other attributes, both qualitative and quantitative. For ...
1
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1
answer
620
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Comparing a list from an arcpy search cursor to a list from a CSV file
I'm attempting to compare entries in a CSV file to entries in a geodatabase using a search cursor through arcpy.
I'm not sure if this is the best way to go about a comparison against these two ...
2
votes
2
answers
626
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How to make two side by side maps match up in layout view in MapInfo?
I am working with two maps that have different thematic elements on each- in this case, I made two different columns to display the concentration of chemical found on that location. I display the ...
0
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0
answers
55
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Visualizing two different datasets amicably when they are measuring two different things
I am working on a story map in AGOL that is comparing the percentage of a population that lives in a house that has been deemed transit dependent versus the concentration of a population that lives in ...
5
votes
1
answer
670
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Difference between OSM regional extracts unexpectedly large
I want to create a difference (change file) between two Europe extracts from OSM data. The files I want to compare are:
http://download.geofabrik.de/europe-180401.osm.pbf
http://download.geofabrik.de/...
1
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0
answers
64
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Light normalization of Orthophotos to increase comparability
I would like to work with the RGB-values of different orthophotos. Now I noticed that the light conditions are not the same in the different orthophotos. I was wondering if there is a sound way to ...
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0
answers
54
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Methods to differentiate between terrain
I am not specialized in GIS.
I have some moisture contour maps, I want to compare each pair to trace the changes between either in a numeric way. I tried to get the mathematical difference between ...
7
votes
1
answer
165
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Why does 3d Bounding Box &&& check return true when I use ST_3DMakeBox?
I'm just wondering why this &&& is returning true when I use ST_3DMakeBox?
SELECT ST_MakePoint(0,0,0) &&& ST_3DMakeBox(
ST_MakePoint(-1,-1,-1),
ST_MakePoint(1,1,-1)
);
...
9
votes
1
answer
1k
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Landsat level-2 data comparison
I'm doing a temporal analysis of NDVI and temperature over 17 years, necessitating data from Landsat 5,7, & 8. I'm interested in using level-2 Landsat data available from https://espa.cr.usgs.gov/...
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1
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1k
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What is the most size-efficient spatial file format for vector polygon data? [closed]
Surprised I couldn't find an answer to this on Google. For transferring a complete dataset (polygons, in vector form) in a single file, what is the most size-efficient file format?
1
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1
answer
2k
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Advantages of OSM over Google Maps for custom map in app
I wanted to map my city on a private map. I have read about maps and I found that I will need tiles. Looking at available service, could not find one that allows me to host them in my server. Which ...
1
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1
answer
67
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Quantifying polygon changes between shape layers in ArcGIS?
I have a map with two shape layers from different years, which are made up of habitat polygons, and are the same shape other than changes to the areas of these habitats.
How do I get a table of the ...
0
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1
answer
209
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Vector maps comparison (looking for a Kappa-like index for vectors) in R?
I am currently trying to compare two shapefiles (representing buildings) in order to validate simulation results. One shapefile contains real data and the other is the product of an urban simulation ...
2
votes
1
answer
1k
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How to compare a TIN and IDW-derived raster DEM quantitatively?
I'm a student and got the assignment to compare a TIN with a height raster 'quantitatively' and I'm not quite sure how to proceed. I tried subtracting the one from the other but it doesn't seem to be ...
7
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3
answers
735
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Checking what changed inside updated shapefile
I am using different shapefiles from open data in Switzerland. They have just updated the whole set. My question is: how to compared two layers (new and old version)? I would like to know the ...
3
votes
1
answer
482
views
Appropriate Japan US comparison map
I would like to create a map in QGIS comparing the relative size and latitudes of Japan to the US. There are a few websites like mapfrappe which allow this using Google Maps, but I would like to be ...
1
vote
0
answers
752
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Compare a DEM and DSM with QGIS
I have a DTM with 40cm resolution and a DSM with 2cm. Now I would like to compare the two so I can identify vegetation that is higher than a certain distance from the ground. I changed the pixel size ...
1
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0
answers
65
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Compare symbols in pyqgis
I'm working with renderers and I want to compare symbols from two different renderers. Is there any way to do it in pyqgis/python?
Here is how I get symbols:
renderer = layer.rendererV2()
category = ...
1
vote
2
answers
6k
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Comparing layers in QGIS and finding overlay?s
I'm a newbie to QGIS. I have run into a thing I can not solve despite trying to search for a solution and working through the functions in the tool.
I have two layers I want to compare. One is filled ...
2
votes
0
answers
53
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Comparing multiple polyline shapefiles to single key file [closed]
I am working on a project where we are comparing participants' spatial memories. We take them through a circuit, then later in the lab they draw the route they traveled. I want to be able to compare ...
4
votes
2
answers
3k
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How can a statistically significant difference between rasters be calculated?
so after some gruelling use of MaxEnt I have four occurrence probability rasters for the four quarters of the year, each one is about 70MB+. I want to test whether they are significantly different ...
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4
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2k
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Searching for changes of 2 layers based on geometry, Arcgis for desktop (ArcEditor
I´m trying to make a tool that would be able to compare 2 layers of any type (polygon, point, polyline) and find differences between them. Lets say i have a layer of roads (Polyline) from 2005 (layer ...
0
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0
answers
88
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ArcPy FeatureCompare vs. FileCmp
I have a huge number of shape files that I receive on a recurring basis. I want to be able to compare the new version to the current version, and then only update the db with those that are different.
...
2
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0
answers
122
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Can 2 GIS layers which representing the same area be compared directly while having the same datum but different coordinate system?
My question is about how coordinate systems affect comparison of different layers - I have tried to refresh my memory about coordinate systems in GIS, but am still unsure about this situation.
I am ...
11
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1
answer
6k
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Identifying overlapping time intervals with two more criteria in R?
I have to check birds observations made over a longer period for duplicate/overlapping entries.
Observers from different points (A,B,C) made observations and marked them on paper maps. Those lines ...
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2
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115
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Can I change the pimary key for feature class comparisons with ArcPy
I'm using ArcPy to compare two feature classes from Esri file geodatabases using the Feature Compare (Data Management) tool.
The script itself works very well. However it always uses the OBJECTID to ...