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12

As always, it depends ... :-) I see at least 3 different scenarios when time is involved. 1) The time part is different inside a geometry. A track log from a GPS for instance, if you make a linestring from that. Then you will have different timestamps for each vertex inside the linestring, and you can interpolate a calculated time at any place on the ...


10

Here's a little QGIS python function that implements this. It requires the rasterlang plugin (the repository has to be added to QGIS manually). It expects three mandatory parameters: The points layer, a raster layer (to determine the size and resolution of the output), and a filename for the output layer. You can also provide an optional argument to ...


9

The idea is good but the proposed implementation may be too simplistic to be credible. Rents are a property of economic systems. Besides being influenced by location, they are related to other economic variables in important ways: state of the local (and national) economy, local housing prices, availability of capital, employment rates, etc. To do a good ...


9

I found this report via Free Geography Tools. The GPS units test results shown here are near the end of the report.


9

Yes, it is possible but using a Python script in the console see For geologists: 3D geological boreholes I presented the scripts in visualizing 3D data (Z values) or data with z attribute: a solution or QGIS, représentation 3D des couches vectorielles (shapefiles dits 3D ou shapefiles avec attributs z) avec les modules Python Matplotlib ou Visvis à ...


8

This book isn't specifically about data modeling, but I have found it particularly useful for working with spatial data in SQL Server. http://www.amazon.com/Beginning-Spatial-Server-Experts-Voice/dp/1430218290 There is also a newer book that will be more advanced and focused on SQL Server 2012, but I haven't looked at this myself yet. ...


7

Here is a demo from the Esri Site http://resources.esri.com/help/9.3/arcgisserver/apis/javascript/arcgis/help/jssamples_start.htm#jssamples/gp_bottle.html and here is the GP model that is used http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_Currents_World/GPServer/MessageInABottle


7

As scw says in his comment the code itself seems to make use of some basic processing and loops so could probably be rewritten quite quickly in Python and Shapely. However if you are looking for a script take a look at the following written in R..and German: http://www.reymann.eu/wp-content/uploads/2010/06/GravitationsgesetzHuff.R Google Translate seems ...


7

As a very gentle introduction to topics on spatial regression I would highly recommend checking out the GeoDa workbook (chapters 22 to 25 will be of most interest). Even if you don't want to use the software it is a very comprehensive overview of spatial regression. Will the built in regression functions in ArcMap handle that much data (not that any ...


7

See Moskitt Geo for this. Some demos available on youtube http://www.youtube.com/watch?v=ed-Sb66llXY and http://www.youtube.com/watch?v=motlsfzFXn0 For the moment, there are some problems with type for generated sql. After not especially for gis database but PostgreSQL in general, see SQL Power Architect DBDesigner fork PgModeler The first use JDBC, so ...


6

An alternative that is well known in some circles but seems not to be known at all within GIS is Multi-attribute Value Theory. This is a theoretically well-grounded way to establish accurate scoring methods involving two or more characteristics (attributes). It proceeds by systematically considering trade-offs among attributes. With suitability problems, ...


6

In the case of changing political and other administrative boundaries I think the Great Britain Historical GIS had a good way of handling the problem, the structure of the data base is described at http://onlinelibrary.wiley.com/doi/10.1002/9780470987643.ch13/pdf and a large number of related papers can be seen at ...


6

Use focal statistics instead of block statistics: when using rectangular neighborhoods this produces the same results in the centers of the blocks, but focal stats are computed with moving (overlapping) windows, effectively creating a representation of a surface of relative slopes. Moreover, focal stats can be computed with more natural neighborhoods, such ...


5

As @Mapperz has rightly pointed out this phenomena effects only US. There has been widespread concerns on this issue and a Coalition to Save Our GPS has been formed with a mission - Uniting to Protect GPS - A National Utility for More Than 30 Years. The site contains wide variety of resources on the issue in the form of White Papers, Studies and Reports, ...


5

ArcGIS 10 has it covered well http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Supported_field_formats/005z00000006000000/ and best practices http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Best_practices_for_storing_temporal_data/005z00000005000000/


5

I suspect the easiest way to do it would be through Python (or VBA). Start by putting your model together, including parameters for the input and output variables. Then from the model menu export the model to a Python script Open the script in an editor of your choice (I use Eclipse with the Pydev extension, but Notepad++ works, as does IDLE). Simply set ...


5

One term used to describe this issue is the 'Modifiable Areal Unit Problem' and a paper I read on this topic is Excess commuting and the modifiable areal unit problem. The authors' approach is to examine the analysis at a few different spatial scales to look at what point convergence occurs. This is a satisfactory solution for examining one parameter, but ...


5

Assuming that money is no object, then yes, you can have all three at the same time. You'll have to invest in very robust hardware and video for starters. The difference between "games" and GIS when it comes to "game like speed" is that games have the luxury of catering the environment to the strengths of the video card and memory. The real world cannot ...


5

The short answer is that there isn't one especially if you're looking for a TransCAD or Emme/2 alternative as there is no open source package that comes close to those. The closest you can get are some micro modelling solutions like Transims or matsim that I find lacking of a lot of needed data, methodologies, tools, or network handling that are available ...


4

Aspect, height, and slope all come from the same raster source originally, so the nice thing about continuing to use rasters is you can keep the same resolution for these inputs without losing information due to re-sampling. (This paragraph mostly null & void if you're using other sources of data at a lot of other resolutions. :) ) A useful extension ...


4

It seems like there should be a way to derive AS from a skyline graph created using the ArcGIS 10.0 3D analyst. If you have a skyline (3D polyline) that surrounds an observation point, it should be able to step through each vertex on the skyline and find some portion of a sphere that is visible. Or, if you moved each vertex so that it is one unit ...


4

3D Analyst can visualize existing models exported from other applications as 3D DXF but it's very difficult (if not impossible) to create subsurface geology solids in ArcGIS. Geological 3D modelling software = VERY expensive (But that is not a part of your question) My personal favorite for subsurface modelling and 3D interpolation is Leapfrog Mining by ...


4

I'm currently working with Vue Infinite 10.5 to bring in real-world elevation and point location data, and it hasn't been easy. Vue is a high-end 3D scenery solution used extensively by Hollywood. We chose it because it is capable of producing photo-realistic 3D visualizations at a reasonable price (about $1000 USD) and it has a Python API. Vue doesn't ...


4

I have encountered some papers and talks on this and related field through my work on Risk Analysis, the journal of the Society for Risk Analysis. The most relevant recent paper is A Risk-Based Approach to Setting Priorities in Protecting Bridges Against Terrorist Attacks. Risk Analysis Volume 24, Issue 4, August 2004, Pages: 963–984, Maria Leung, James ...


4

This looks interesting: "ACTIVE VS. PASSIVE DEFENSE AGAINST A STRATEGIC ATTACKER" (their caps, not mine). While it doesn't explicitly address GIS, it seems like spatial analysis could be used in determining the vulnerability component of the model.


4

The short answer is 'yes'. In both QGIS and ArcGIS, you want to use the raster calculator. Each has its own syntax so check the documentation (see links below) for which ever one you are using. However, essentially, you can type a formula in the raster calculator along the lines you need. You can also use the raster calculator to do "mapematics" ...


3

Sue Greenlee's original code - that Esri's and many other watershed codes are based on - was published in FORTRAN in 1988. I'd go looking for that - don't see it on the web - but you could always email her! Kind of surprised it's not in GitHub, it's pretty neat code. Jenson S. K. and J. O. Domingue. 1988. Extracting Topographic Structure from Digital ...


3

It is actually a whole segment of physical oceanography, with the ocean circulation modelling generally done in matlab. The particular models involved are much more relational than spatially explicit, making them more suited to matlab than gis packages. If you have access to a physical oceanographer, I would highly suggest asking them about this problem. As ...


3

Some (slightly) theoretical pointers: Instead of focusing on attributes, one approach to the problem might focus on exploring characteristics of movement patterns. Those could be explored by calculating aggregated characteristics of movement or dividing your data into logical 'chunks' (for instance, daily trajectories of certain objects). At next stage you ...


3

TLDR: Combined Arms doctrine renders terrain defense moot. This area of study is referred to as terrain defense doctrine. The modeling you are proposing is possible, but would almost always return no result if the attack vectors are modern (air). Because terrain is rendered moot if you can fly. This type of modeling is usually only considered against ...



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