QGIS Plugin Research Articles

A Suite of Tools for Assessing Thematic Map Accuracy

Although land use/cover maps are widely used to support management and environmental policies, only some studies have reported their accuracy using sound and complete assessments. Thematic map accuracy assessment is typically achieved by comparing reference sites labeled with the “ground-truth” category to the ones depicted in the land use/cover map. A variety of sampling designs are used to select these references sites. The estimators for accuracy indices and the variance of these estimators depend on the sampling design. However, the tools used to assess accuracy available in the main program packages compute the accuracy indices without taking into account the sampling and give inconsistent estimates. As an alternative, we present free user-friendly tools that enable users beyond the Geographic Information Science Community to compute accuracy indices and estimate corrected areas of given categories with their respective confidence intervals. The tool runs in Dinamica EGO, a free platform for environmental spatial modeling as well as a Q-GIS plugin and a R package. Additionally, a practical application example is described using a case study area in central-west Mexico.

An Association Rules Based Approach to Predict Semantic Land Use Evolution in the French City of Saint-Denis

This paper proposes a predictive approach of semantic land use changes based on data mining techniques, specifically association rules (AR). Its main idea is centered around studying the past to predict the future. In other words, applying association rules technique to discover rules governing the city's past land use changes, then use them to forecast future changes. Taking La Plaine Zone in the city of Saint-Denis as a study case, the authors applied the proposed approach, in the framework of a developed Qgis plugin (Predict). The results are then highlighted in a cartographic format. To assess the quality of semantic land use changes prediction using our predictive approach, the authors proposed the Prediction precision degree (P) as an evaluation metric. A resulting value of 66% is considered promising since in this case, the authors only relay on history of land use changes for the prediction process, while considering some other evolution factors could remarkably enhance the results.

Quantum GIS plugin for Czech cadastral data

This paper presents new Quantum GIS plugin for Czech cadastral data and its development. QGIS is a rapidly developing cross-platform desktop Geographic Information System (GIS) released under the GNU GPL. QGIS is written in C++, and uses the Qt library. The plugin is developed in C++, too. The new plugin can work with Czech cadastral data in the new Czech cadastral exchange data format called VFK (or NVF). Data are accessed through VFK driver of the OGR library. The plugin should facilitate the work with cadastral data by easy search and presenting well arranged information. Information is displayed in the way similar to web applications, thus the control is friendly and familiar for users. The plugin supports interaction with map using QGIS functionality and it is able to export various cadastral reports. This paper provides ideas which can be generalized to develop QGIS plugin dealing with specific data.

Determination of anti-inflammatory activity of terpenoide fractions of some Artemisia species from Iran

Environmental monitoring has become of paramount importance for researchers and decision makers in order to better protect the environment and achieve sustainable development goals, especially with continuous population growth and rapid urbanization and industrialization processes that alter natural components of the environment and degrade the ecosystems. Hence, the use of Landsat data is of great significance, particularly in environmental monitoring and land management, due to their high spatial resolution and their free of cost availability since 1972. However, calculation of remotely sensed indices for environmental purpose occurs in several steps and requires minimum knowledge in imagery processing. This paper describes the development and design of Q-LIP “QGIS-Landsat Indices plugin”- a simple and easy-to-use tool to download, process and automatically calculate environmental indices from Landsat imagery. Q-LIP has been built under Python and designed as a QGIS software plugin; it is available to download from QGIS Plugin Repository.

Maps2WinBUGS: a QGIS plugin to facilitate data processing for Bayesian spatial modeling

For Bayesian spatial modeling, GeoBUGS, part of WinBUGS (OpenBUGS) is a widely used tool. The map format used by GeoBUGS differs from the standard formats used in geographical information systems (GIS). The QGIS plugin, maps2WinBUGS, helps the user prepare maps and tabular data for use in GeoBUGS. With this tool, one can obtain adjacency lists, convert maps, and merge back the results of model runs with a source map in QGIS. Through script wizards, users can generate R scripts from their own data (QGIS supported vector format map, attribute data) using different models.

Deriving Hydrological Response Units (HRUs) using a Web Processing Service implementation based on GRASS GIS

QGIS releases equal to or newer than 0.7 can easily connected to GRASS GIS by means of a toolbox that provides a wide range of standard GRASS modules you can launch – albeit only on data coming from GRASS. This QGIS plugin is expandable through XML configurations describing the assignment of options and inputs for a certain module. But how about embedding a precise workflow where the several processes don’t consist of a single GRASS module by force? Especially for a sequence of dependent tasks it makes sense to merge relevant GRASS functionality into an own and encapsulated QGIS extension. Its architecture and development is tested and combined with the Web Processing Service (WPS) for remote execution using the concept of hydrological response units (HRUs) as an example. The results of this assay may be suitable for discussing and planning other wizard-like geoprocessing plugins in QGIS that also should make use of an additional GRASS server.