Questions tagged [comparison]

The act of comparing or the process of being compared.

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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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91 views

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 ...
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53 views

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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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 ...
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53 views

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 ...
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29 views

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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27 views

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 ...
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395 views

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 ...
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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 = ...
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87 views

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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364 views

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....
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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 ...
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27 views

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 ...
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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. ...