Questions tagged [modelling]

A methodology or set of analytical procedures used to derive information about spatial relationships between geographic phenomena.

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Is there QGIS plugin to allow 3d visualisation of geological borehole data similar to functionality of Target for ArcGIS?

I'm very new to QGIS, I have started using it as my new company is not willing to pay for ArcGIS and Target at this stage so I'm hoping QGIS can substitute not just in the interim but for good. What ...
Ben's user avatar
  • 81
2 votes
3 answers
1k views

Extract by expression - N first

How can I "extract by expression" the N first (10 highest values of one column, for example) I need it for the graphical modeler.
Adrian Alonso-Frontela's user avatar
14 votes
2 answers
5k views

Open-source GIS implementation of the Huff model

This might be a stretch, but I was wondering if anyone implemented gravity modeling tools or scripts for Retail Market Analysis (like the Huff Model), to analyze spatial data for customer-store ...
RyanKDalton's user avatar
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10 votes
6 answers
2k views

seeking "Available Sky" implementations

I'm looking for implementations of an algorithm called "Available Sky". ArcGIS (Spatial Analyst or GRID) is preferred, but solutions in GDAL, SAGA GIS or others are perfectly acceptable. The ...
matt wilkie's user avatar
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9 votes
2 answers
13k views

Creating noise maps using ArcGIS for Desktop or Open Source Desktop GIS? [closed]

In a previous role I helped create Noise Maps for Northern England. The predicted noise levels was done using the IMMI package (which I can recommend) and the cartographic output was done in ArcMap. ...
jakc's user avatar
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5 votes
2 answers
1k views

Compound variables in Model Builder?

I'm trying to create a model wherein one of the parameters is a compound variable, that is made of multiple variables joined together. How can this be done? For example: create an insider buffer ...
matt wilkie's user avatar
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17 votes
3 answers
625 views

Lightsquared GPS controversy: Where is the analysis?

GPS World reports that Lightsquared's network of 40,000 transmitters will interfere with GPS signals. Initial technical analyses have shown that the distant, low-powered GPS signals would ...
Kirk Kuykendall's user avatar
16 votes
7 answers
4k views

What are some 3D visualisation tools that successfully work with GIS data?

There are a large number of 3d modelling tools available (both open and closed source). I would like to be able to: Import GIS data into a 3d environment and retain georeferenceing. Retain the ...
16 votes
4 answers
912 views

How to handle TIME in GIS?

Is there any way or any idea on how to handle Time attribute in GIS? For example, which are the ways to specify that an object is at a place at a given time interval and them it is in another place ...
Pablo's user avatar
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16 votes
3 answers
3k views

Is there a CASE Tool for modelling spatial databases?

Does anyone knows if there is a CASE Tool that would be possible for modelling spatial tables? I need to create a model and export it to SQL or a database directly. I'm using PostGIS.
Marcello Benigno's user avatar
14 votes
3 answers
702 views

What practices are available for modelling land suitability?

I currently use a "classic" raster based approach of dividing a study area into cells. All input layers are converted to rasters at the same cell resolution and given a suitability rating. A final ...
geographika's user avatar
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8 votes
1 answer
417 views

Opening old QGIS model in current QGIS versions

There is an older answer by @underdark to this post: Finding centrelines from polygons in QGIS? She links a QGIS model that apparently was created in QGIS 2.12. It has the file extension .model When I ...
Babel's user avatar
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6 votes
2 answers
8k views

Variogram model fit compatability among geoR, gstat, and nlme packages in R

I'm trying to specify the covariance structure parameters in a linear mixed model (using the correlation structure facilities in nlme). The parameters are estimated from a gstat or geoR variogram ...
adamdsmith's user avatar
5 votes
3 answers
2k views

Calculating changes in slope angle between cells/areas using ArcGIS Desktop?

I am doing an estimation of erosion with ArcGIS. I use the UniversalSoilLossEquation (USLE) for this. Now, i want to calculate the L-factor of this equation. I need the FlowLength for this. My ...
Markus's user avatar
  • 51
4 votes
1 answer
1k views

Moving window regression (MWR) in R?

I'm looking for some package in R to estimate the value of a variable by moving window regression. I have read in Local Models for Spatial Analysis, which is a good method to predict values ​​at ...
jmbluengo's user avatar
  • 111
2 votes
1 answer
343 views

3D model of rooftops based on LiDAR and cadastral data?

I´m trying to model building rooftops based on a LiDAR dataset. I've already interpolated using Delaunay's triangulation a DEM with 1 meter resolution. Due to LiDAR data is not accurate in building ...
Adrian Palma's user avatar
2 votes
0 answers
601 views

Modelling Zombie Outbreak

I know that there are many scripts (mostly in matlab) out there that address the spread of disease/zombie infection, but does anyone know of ways this has been developed/implemented in ArcGIS? ...
CodeSpatial's user avatar
1 vote
0 answers
362 views

Automatic Roof Modelling on QGIS

I have an area that I am modelling using QGIS, I have each building outline, and I extrude it via qgis2threejs. I wish to add another level of detail and model the roof of each house, which doesn't ...
R Kumar's user avatar
  • 211
1 vote
2 answers
1k views

How to delete multiple columns in the QGIS processing model?

I made the union of two tables I want to erase some columns. How can I do this automatically?
Endi Soares's user avatar