Gábor Timár

Crop yield estimation by satellite remote sensing

Two methods for estimating the yield of different crops in Hungary from satellite remote sensing data are presented. The steps of preprocessing the remote sensing data (for geometric, radiometric, atmospheric and cloud scattering correction) are described. In the first method developed for field level estimation, reference crop fields were selected by using Landsat Thematic Mapper (TM) data for classification. A new vegetation index (General Yield Unified Reference Index (GYURI)) was deduced using a fitted double-Gaussian curve to the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) data during the vegetation period. The correlation between GYURI and the field level yield data for corn for three years was R 2=0.75. The county-average yield data showed higher correlation (R 2=0.93). A significant distortion from the model gave information of the possible stress of the field. The second method presented uses only NOAA AVHRR and officially reported county-level yield data. The county-level yield data and the deduced vegetation index, GYURRI, were investigated for eight different crops for eight years. The obtained correlation was high (R 2=84.6–87.2). The developed robust method proved to be stable and accurate for operational use for county-, region- and country-level yield estimation. The method is simple and inexpensive for application in developing countries, too.

Controls on channel sinuosity changes: a case study of the Tisza River, the Great Hungarian Plain

Abstract The planform geometry of the Tisza, the trunk river of the subsiding Great Hungarian Plain is studied by reconstruction of the last pre-regulation river course. The thalweg sinuosity has been computed for the main alluvial section of the river. Remarkable sinuosity changes have been found to correlate with discharge and sediment load changes at the inflow of tributaries, as well as with active deformation areas, like differential subsidence and wrench fault zones. Analysing the change of the river pattern, a new discrimination line has been derived, which separates the meandering zone on the classic slope vs. discharge diagram into two subzones. The first subzone (lower slope values) corresponds to a range of true, self-organized meandering. The second subzone (higher slope values) corresponds to a range of ‘unorganized meandering’. This is a range where river sinuosity decreases although the channel slope increases. In the case of the Tisza River, this subzone equals to the wandering river pattern.

Digitized Maps of the Habsburg Military Surveys – Overview of the Project of ARCANUM Ltd. (Hungary)

This paper summarizes and overviews the scientific, technical and legal background of the rectifying project of the Habsburg Military Survey sheets at the Hungarian firm Arcanum. Rectified versions of the whole First, Second and Third Surveys are completed, however, till this moment, only the Hungarian part of the First and Second Surveys (in 1:28800 scale) were published together with the full Third Survey (in 1:75000 scale) because of legal issues. The rectification errors are quite high in case of the First Survey; this accuracy fits only for settlement finding applications. Accuracy of the Second Survey is surprisingly good in most parts of the Empire, the maximum error is cca. 200 meters, the same value that characterizes the Third Survey, too. This new, electronic cartographic version of the old map systems offers excellent possibilities to follow the changes of the natural and built environment of Central Europe in the last two and a half centuries.

Tertiary brittle faulting and stress field evolution in the Gerecse Mountains, northern Hungary

Abstract The Gerecse Mountains of the Transdanubian Range in northern Hungary have suffered polyphase deformation during the Tertiary. The evolution of the stress fields was determined by the detailed structural survey of the area: the statistical analysis of microtectonic observations, the mapping and reinterpretation of fault pattern and the study of basin stratigraphy and geometry. The stress fields show an apparent clockwise rotation from Eocene until Quaternary times. Three main phases were reconstructed. During the Eocene-Early Oligocene E-W- to ENE-WSW-oriented compression and perpendicular tension affected the area. The formation and evolution of several sedimentary basins were controlled by fault systems activated by this phase. After a period of intensive erosion in the Early Oligocene the stress field rotated approx, 30–40°: NW-SE-directed compression and NE-SW-trending tension existed during the Late Oligocene and Early Miocene. After correction with palaeomagnetic data, an original Palaeogene σ 1 orientation is deduced NNE-SSW, reflecting the collisional processes of Europe and the Apulian microplate. The Middle Miocene to Pliocene period was characterised mainly by extensional deformation: the direction of the minimal stress axis ( σ 3 ) varied between E-W and NW-SE. The characteristic clockwise rotation pattern of the Tertiary palaeostress fields in the Gerecse Mts. is explained by the combined effect of the regional stress field changes in the Carpatho-Pannonian region and the rotation of the North Pannonian Unit.

Yield forecasting for wheat and corn in Hungary by satellite remote sensing

We have developed an advanced version of our yield estimation method [Ferencz et al., 2004, Crop yield estimation by satellite remote sensing. International Journal of Remote Sensing, 25, pp. 4113–4149], that is able to provide reliable forecasts for corn and wheat, several weeks before the harvest. The forecasting method is based on the data of the Advanced Very High Resolution Radiometer (AVHRR) instruments of the National Oceanic and Atmospheric Administrations (NOAA) Polar Orbiting Environmental Satellites (POES). The method was applied to Hungary between the years 1996 and 2000. The forecasted yield values are all within 5% reliability with respect to the actual yield data produced by classic (non-satellite based) methods and provided by the Hungarian Statistical Office, with the exception of 1997, where the absolute error is about 8%.

Orientation of the Map of Lazarus (1528) of Hungary – Result of the Ptolemian Projection?

The strange orientation of the map of Lazarus (1528) has been a subject of a long debate of Hungarian cartographers in the 20th century. In this map, northeast is up, instead of the normal and traditional orientation where the north is up. It was long ago supposed that this orientation is a result of the local/regional usage of the Ptolemian projection of the world maps of the age of the map construction. If a Ptolemian conic projection is defined in the GIS environment with the parameters of Ф1=0°, Ф2=64°and Λ0=90° (from Greenwich), interestingly enough, the map can be rectified and the resulted image has right angles at its corners and all sides are horizontal or vertical in the Ptolemian coordinate system but not, of course, in the modern ones. The linear rectification errors in this projection are more or less equal to the quadratic ones in fitting to modern coordinate systems eg. to a UTM zone. This suggests that the above projection can be considered at least as a substituting one or even the real projection of the Lazarus map. If we consider this projection as a Ptolemian one, it leads to a more general indication: the Ptolemian projection used also by Lazarus has two standard parallels, the Equator and the Northern Circle, which is more or less the same as the mysterious Parallel of Thule in the maps of Ptolemy. In the map, however, the main directions are rotated by 90°; the grid north points to the original left indicated by the word ’Occidens’ (west), which is considered as an error of the press preparation.

The first scientific description of aurora borealis: the 10 September 1580 event in Transylvania, recorded by Marcello Squarcialupi

The first scientific treatise on aurora borealis was published by Marcello Squarcialupi, an Italian medical doctor working in the court of the Hungarian Prince of Transylvania. His book, De coeloardore, described the aurora of 10 September 1580 in great detail, providing exact data from his personal observations on the time, direction, shape, colour, and variability. He invoked a rational explanation, bringing up only natural causes, and confronted these with the ruling Aristotelian view. The original Latin text describing the aurora is provided, with an English translation.

DEM-derived markers of drainage network changes in the Eastern Alpine Foothills

The study area is situated between the uplifting Alps and the subsiding Little Hungarian Plain, between 16°–17° E and 47°–47.5° N. The differential vertical motion implies neotectonic activity and some associated geomorphologic features (e.g. wind gaps, small streams in large valleys, etc.) may be observed as a result of drainage reorganization. After ∼8.7 Ma the area was characterized by a wide alluvial plain and a marsh zone. Later on, rivers spread their gravelly sediment over the whole area, creating gravel terraces in the west and an almost continuous gravel cover in the eastern, planar terrain. The drainage network in the hilly region is oriented to the NW–SE alluviation direction, but each river has several abrupt turns in its lower course. In order to identify wide and planar features some DEM-derived markers were used. First, two parameters were considered for each pixel: slope angle and relative height. Second, two parameters were used to classify wind gaps: incision of the valley bottom and relative elevation. In our case, the less uplifted, but more deeply incised valleys are the most obvious markers of drainage reorganization. Using the mentioned methods, terraced valleys, wide alluvial valleys and deeply incised valleys, as well as wind gaps, are recognizable and help interpretation of former river connections. The spatial pattern of the identified wind gaps suggests that drainage reorganization was significantly influenced by north-facing escarpments. Therefore, the map provides additional information to the scientific debate concerning the post-Miocene tectonic activity of the Eastern Alpine Foreland.

The Austro-Hungarian Triangulations in the Balkan Peninsula (1855–1875)

The Turkish part of the Balkan Peninsula was an area of extensive geodetic surveys between 1854 and 1875. These works were carried out by the Austro-Hungarian authorities, partially in the frame of the International Arc Measurements (International Gradmessung). These activities were made in the present territories of Bosnia-Herzegovina, Albania, Montenegro, southern Serbia and Kosovo, Bulgaria, southern Romania, Macedonia and also northern Greece. Astronomical points were measured throughout the area, mainly along travel routes of the surveying parties, and then other points, mainly mountain peaks, were determined by triangulation (intersection) from the astronomical points. No geodetic network adjustment was applied to the point sets. Based on these geodetic base point data, 1:75,000 scale maps of the Austro-Hungarian Monarchy was issued from the 1880s to WWI, as well as local Serbian maps after the independency of the state. The existing geodetic datasets formed the base of the utilization of the Hermannskogel datum in the later Yugoslavia, even the territories that were not part of the Habsburg Empire. For present GIS applications it should be underlined, that the Yugoslav version of the Hermannskogel datum used a different Ferro-Greenwich longitude shift, thus the datum description parameters differ from the ones used in Austria.