3. Acorazamiento del lecho La hipótesis de la “igual movilidad” iba íntimamente vinculada al
2.4 Determinación de las tasas de transporte
2.4.2. Fórmulas teóricas
Table 2 provides a summary of the test results described in the previous sections. Table 4: Summary of test results achieved
TEST NAME SUMMARY
Test 1: Buffering an area of operations (4.2)
The results obtained are similar.
In order for the GIS operator to successfully complete the buffering process in QGIS, he/she will need to have a basic understanding of coordinate reference systems.
The unit of measurement in QGIS cannot be chosen in the buffer analysis dialog.
Test 2: Cholera hotspot analysis (4.1)
The hotspot analysis was successfully completed in both software products.
A difference in the results obtained was observed.
In QGIS, more detail is visible and the resulting polygons appear to be slightly smoother.
The buffer area sizes created in QGIS are approximately 104 km², whereas in ArcGIS the buffer sizes are 44 km². Therefore a significant difference of approximately 60 km² of extra buffer areas are displayed created QGIS.
In ArcGIS, the kernel density estimation is based on the quadratic kernel function (by default) and in QGIS the Quartic (biweight) kernel function/shape was selected.
Test 3: Creating a visibility layer (4.3)
The desired end-result could be achieved in both products.
In ArcGIS, the process of initially entering the input values for the observer point is a bit more complex in QGIS than in ArcGIS 10.2. In QGIS, the required attributes were automatically available in the
“Viewshed analysis” plugin. ArcGIS 10.3 has resolved this in the new “Viewshed 2” tool.
The inexperienced user might consider the styling in QGIS to be more complex than in ArcGIS. The result in QGIS displays as a single band greyscale, which must then be changed to a single band pseudocolour and classified.
The legend in QGIS was renamed to indicate “Visible” and “Not- visible”, which was done by default in ArcGIS, but can also be edited if needed.
Test 4: Creating a water purification plants layer (4.4)
In ArcGIS, the styling of the point symbols was made easy by the wide variety of existing symbols available.
In QGIS, the number of point symbols for point features was limited. Additional point symbols were downloaded from the internet in .SVG format.
In a military operation where internet services might not be available, this part of the process will have to be done as part of deployment preparation.
On the plus side of symbology with QGIS, new symbols can be created by the user by combining more than one symbol.
The slope analysis (needed to determine the ideal location of water purification plants) in both ArcGIS and QGIS was effective in applying a degree slope.
In the ArcGIS Slope analysis tool, there is an additional option to perform a “percentage slope” analysis.5
Conclusion
From an empirical study and using a use case, certain operational level GIS functionalities were identified. These GIS functionalities were tested on both proprietary GIS software (ArcGIS) and using FOSSGIS (QGIS) and the outcomes were qualitatively compared. The following conclusions were derived from the study:
i. Firstly, all the operational GIS functions described in the use case could successfully be performed using both ArcGIS and QGIS.
ii. It is acknowledged that some of these GIS functions were on an advanced level and that in both software products training will therefore be needed.
iii. Although all GIS functionalities could be performed using both software products, in most cases where the analysis result was in a raster format, the properties of the end-result in QGIS needed further “refining” since the raster output is first displayed as a singleband greyscale image. Although this is not significantly difficult to perform, the GIS operator will have to take cognisance of this aspect.
iv. The default existing library of symbology within ArcGIS (especially with regards to point symbols) is more comprehensive than in QGIS. However, it is also possible to expand symbology in QGIS in two ways. For this further training and subject matter experience is required:
1. Firstly, by downloading additional symbols in SVG format. 2. Secondly, by designing symbols.
The fact that the native symbology functionality in ArcGIS exceeds that of QGIS, makes ArcGIS the software of choice when it comes to extensive military cartographic products. Units or directorates that produce maps and cartographic products on a large scale should therefore use ArcGIS as their primary cartographic tool.
With regards to the GIS functionalities tested, it can be concluded that FOSSGIS can be successfully deployed to units or directorates, especially to those with limited funds, to expand the existing GIS capabilities for military operations. This process will however require guidance and training. Without proper training and guidance any GIS can become a “dangerous tool”.
Nevertheless, it needs to be acknowledged that when certain fees are paid to a proprietary software vendor, one can expect to receive a certain level of service or support from that vendor. This means that if the user encounters a problem with the software (for example a bug in its development), it can be reported and whilst it might not always be fixed immediately, the user can at the very least expect an answer. This can be crucial when troubleshooting in a mission-critical military operation. The FOSS community is aware of this need, and one of the solutions is the (paid) technical support offered by a variety of companies on the QGIS website.
FOSSGIS, and more specifically QGIS, opens a world of possibilities to the military. It means that institutions that would normally be deprived of this great planning tool because of costs can now have access to it. These units have access to the analytical power of an advanced GIS tool with all the functionalities needed to answer the commander’s questions. Although the level of employment of FOSSGIS by military institutions will vary, it is recommended that it should be used in collaboration with proprietary GIS software when used in support of military operations. This will ensure that greater access by military personnel to GIS functionalities is achieved. QGIS is a growing GIS tool and we predict that its use in the military will also grow as employees are trained up in QGIS and their knowledge and experience increase and develop to the same levels they currently have in other software products.
According to Abizad (19 December 2001), a force multiplier is “A capability that, when added to and employed by a combat force, significantly increases the combat potential of that force and thus enhances the probability of successful mission accomplishment”.
FOSSGIS has the potential to be a force multiplier in the military!
6
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