El formato ráster se fundamenta en la división del área de estudio en una matriz de celdillas, generalmente cuadradas. Cada una de estas celdillas recibe un único valor que se considera representativo para toda la superficie abarcada por la misma.
When someone mentions “presentation” invariably Microsoft’s PowerPoint comes to mind. PowerPoint slides, and even entire presentations, can be easily incorporated into story map map tours, and can provide some extra context for your tour.
Most imagery for use in GIS projects consist of satellite images or aerial photographs but it can also include, thermal images, digital elevation models (DEMs), scanned maps and land classification maps.
The greatest obstacle to soil erosion modelling at larger spatial scales is the lack of data on soil characteristics. One key parameter for modelling soil erosion is the soil erodibility, expressed as the K-factor in the widely used soil erosion model, the Universal Soil Loss Equation (USLE) and its revised version (RUSLE). The K-factor, which expresses the susceptibility of a soil to erode, is related to soil properties such as organic matter content, soil texture, soil structure and permeability. With the Land Use/Cover Area frame Survey (LUCAS) soil survey in 2009 a pan-European soil dataset is available for the first time, consisting of around 20,000 points across 25 Member States of the European Union. The aim of this study is the generation of a harmonised high-resolution soil erodibility map (with a grid cell size of 500 m) for the 25 EU Member States. Soil erodibility was calculated for the LUCAS survey points using the nomograph of Wischmeier and Smith (1978). A Cubist regression model was applied to correlate spatial data such as latitude, longitude, remotely sensed and terrain features in order to develop a high-resolution soil erodibility map. The mean K-factor for Europe was estimated at 0.032 t ha h ha− 1 MJ− 1 mm− 1 with a standard deviation of 0.009 t ha h ha− 1 MJ− 1 mm− 1. The yielded soil erodibility dataset compared well with the published local and regional soil erodibility data. However, the incorporation of the protective effect of surface stone cover, which is usually not considered for the soil erodibility calculations, resulted in an average 15% decrease of the K-factor. The exclusion of this effect in K-factor calculations is likely to result in an overestimation of soil erosion, particularly for the Mediterranean countries, where highest percentages of surface stone cover were observed.
Elizabeth Borneman explores how cartography and cartographic projections help and hinder our perception of the world. The post Cartographic Anomalies: How Map Projections Have Shaped Our Perceptions of the World appeared first on GIS Lounge.
O Novo Código Florestal Brasileiro (Lei nº 12.651/2012), aprovado em 25 de maio de 2012, foi fruto de anos de polêmicos embates entre os denominados ambientalistas e a classe que representa o agronegócio brasileiro.