979 resultados para Delaware Bay Region (Del. and N.J.)--Maps, Tourist.
Resumo:
Among the soils in the Mato Grosso do Sul, stand out in the Pantanal biome, the Spodosols. Despite being recorded in considerable extensions, few studies aiming to characterize and classify these soils were performed. The purpose of this study was to characterize and classify soils in three areas of two physiographic types in the Taquari river basin: bay and flooded fields. Two trenches were opened in the bay area (P1 and P2) and two in the flooded field (P3 and P4). The third area (saline) with high sodium levels was sampled for further studies. In the soils in both areas the sand fraction was predominant and the texture from sand to sandy loam, with the main constituent quartz. In the bay area, the soil organic carbon in the surface layer (P1) was (OC) > 80 g kg-1, being diagnosed as Histic epipedon. In the other profiles the surface horizons had low OC levels which, associated with other properties, classified them as Ochric epipedons. In the soils of the bay area (P1 and P2), the pH ranged from 5.0 to 7.5, associated with dominance of Ca2+ and Mg2+, with base saturation above 50 % in some horizons. In the flooded fields (P3 and P4) the soil pH ranged from 4.9 to 5.9, H+ contents were high in the surface horizons (0.8-10.5 cmol c kg-1 ), Ca2+ and Mg² contents ranged from 0.4 to 0.8 cmol c kg-1 and base saturation was < 50 %. In the soils of the bay area (P1 and P2) iron was accumulated (extracted by dithionite - Fed) and OC in the spodic horizon; in the P3 and P4 soils only Fed was accumulated (in the subsurface layers). According to the criteria adopted by the Brazilian System of Soil Classification (SiBCS) at the subgroup level, the soils were classified as: P1: Organic Hydromorphic Ferrohumiluvic Spodosol. P2: Typical Orthic Ferrohumiluvic Spodosol. P3: Typical Hydromorphic Ferroluvic Spodosol. P4: Arenic Orthic Ferroluvic Spodosol.
Resumo:
The modern generation of Cherenkov telescopes has revealed a new population of gamma-ray sources in the Galaxy. Some of them have been identified with previously known X-ray binary systems while other remain without clear counterparts a lower energies. Our initial goal here was reporting on extensive radio observations of the first extended and yet unidentified source, namely TeV J2032+4130. This object was originally detected by the HEGRA telescope in the direction of the Cygnus OB2 region and its nature has been a matter of debate during the latest years. The situation has become more complex with the Whipple and MILAGRO telescopes new TeV detections in the same field which could be consistent with the historic HEGRA source, although a different origin cannot be ruled out. Aims.We aim to pursue our radio exploration of the TeV J2032+4130 position that we initiated in a previous paper but taking now into account the latest results from new Whipple and MILAGRO TeV telescopes. The data presented here are an extended follow up of our previous work. Methods.Our investigation is mostly based on interferometric radio observations with the Giant Metre Wave Radio Telescope (GMRT) close to Pune (India) and the Very Large Array (VLA) in New Mexico (USA). We also conducted near infrared observations with the 3.5 m telescope and the OMEGA2000 camera at the Centro Astronómico Hispano Alemán (CAHA) in Almería (Spain). Results.We present deep radio maps centered on the TeV J2032+4130 position at different wavelengths. In particular, our 49 and 20 cm maps cover a field of view larger than half a degree that fully includes the Whipple position and the peak of MILAGRO emission. Our most important result here is a catalogue of 153 radio sources detected at 49 cm within the GMRT antennae primary beam with a full width half maximum (FWHM) of 43 arc-minute. Among them, peculiar sources inside the Whipple error ellipse are discussed in detail, including a likely double-double radio galaxy and a one-sided jet source of possible blazar nature. This last object adds another alternative counterpart possibility to be considered for both the HEGRA, Whipple and MILAGRO emission. Moreover, our multi-configuration VLA images reveal the non-thermal extended emission previously reported by us with improved angular resolution. Its non-thermal spectral index is also confirmed thanks to matching beam observations at the 20 and 6 cm wavelengths.
Resumo:
This investigation comprises three parts: (1) the source, mechanism of transport, and distribution of pollen, spores and other palynomorphs in Georgian Bay bottom sediments and a comparison of these data with the contemporary vegetation, (2) the relative significance of fluvial transportation of pollen and spores, and (3) the late- and postglacial history of vegetational and climatic changes in the Georgicin Bay region. Modem pollen and spore assemblages in Georgian Bay do reflect the surrovinding vegetation when preservation and pollen production by the different species are considered and accounted for. Relative pollen percentage and concentration isopoll patterns indicate that rivers contribute large quantities of pollen and spores to Georgian Bay. This is further substantiated by large amounts of pollen and spores which were caught in traps in the Moon, Muskoka, and Nottawasaga Rivers which flow into Georgian Bay. The majority of pollen and spores caught in these traps were washed into the rivers by surface water runoff and so reflect the vegetation of the watershed in a regional sense. In a 12.9 metre long sediment core from northeastern Georgian Bay the relative percentage and absolute pollen concentrations allow correlation of Georgian Bay Lake phases with climatic and forest history. Four distinct pollen zones are distinguished: zone GB IV which is the oldest, reflects the succession from open spruce woodland to boreal forest; zone GB III represents a period of pine-mixed hardwoods forests from about 10,000 to 7,500 years ago. A pine-maplehemlock association dominated in zone GB II, although during the culmination of postglacial warming about 4,000 to 5,000 years ago the Georgian Bay forests had a more deciduous character. Zone GB I clearly shows European man's disturbance of the forest by logging activities.
Resumo:
The upper Bay of Fundy is a critical stopover site for Semipalmated Sandpipers (Calidris pusilla) during their fall migration. However, little is known about factors that influence selection of feeding and roosting sites by these birds, or the extent to which birds move between different sites during their time in the region. Using radio-telemetry, we studied movement patterns, examined habitat use, and tested hypotheses associated with factors influencing foraging and roost-site selection. Movements of radio-tagged sandpipers were tracked in the upper Bay of Fundy in August 2004 and 2005. In 2004, sandpipers from the Minas Basin, Nova Scotia and Chignecto Bay, New Brunswick and Nova Scotia, were tracked, and in 2005, sandpipers were tracked only in Chignecto Bay. Sandpipers were highly mobile in both the Minas Basin 2004 and Chignecto Bay 2005, making daily movements of up to 20 km between foraging and roosting sites, although very little movement was detected in Chignecto Bay in 2004. Migrating sandpipers appeared to select foraging sites based on relative safety, as measured by distance to cover, provided that these sites offered an adequate food supply. Similarly, roosting sandpipers preferred sites that were far from nearby trees that might offer cover to predators. This preference for safe sites became more apparent later in their stay in the Bay of Fundy, when birds were heavier and, therefore, possibly more vulnerable to predation. Semipalmated Sandpipers appear to be flexible during their time in the upper Bay of Fundy, displaying year-to-year and site-to-site variability in movement and mudflat usage. Therefore, multiple, synchronized population counts should be conducted at known roost sites in order to more accurately estimate Semipalmated Sandpiper abundance in this region. Furthermore, in a highly dynamic system where food can be variable, landscape features such as distance to cover may be important factors to consider when selecting candidate sites for shorebird conservation measures.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Among the soils in the Mato Grosso do Sul, stand out in the Pantanal biome, the Spodosols. Despite being recorded in considerable extensions, few studies aiming to characterize and classify these soils were performed. The purpose of this study was to characterize and classify soils in three areas of two physiographic types in the Taquari river basin: bay and flooded fields. Two trenches were opened in the bay area (P1 and P2) and two in the flooded field (P3 and P4). The third area (saline) with high sodium levels was sampled for further studies. In the soils in both areas the sand fraction was predominant and the texture from sand to sandy loam, with the main constituent quartz. In the bay area, the soil organic carbon in the surface layer (P1) was (OC) > 80 g kg(-1), being diagnosed as Histic epipedon. In the other profiles the surface horizons had low OC levels which, associated with other properties, classified them as Ochric epipedons. In the soils of the bay area (P1 and P2), the pH ranged from 5.0 to 7.5, associated with dominance of Ca2+ and Mg2+, with base saturation above 50 % in some horizons. In the flooded fields (P3 and P4) the soil pH ranged from 4.9 to 5.9, H+ contents were high in the surface horizons (0.8-10.5 cmol(c) kg(-1)), Ca2+ and Mg-2 contents ranged from 0.4 to 0.8 cmol(c) kg(-1) and base saturation was < 50 %. In the soils of the bay area (P1 and P2) iron was accumulated (extracted by dithionite - Fed) and OC in the spodic horizon; in the P3 and P4 soils only Fed was accumulated (in the subsurface layers). According to the criteria adopted by the Brazilian System of Soil Classification (SiBCS) at the subgroup level, the soils were classified as: P1: Organic Hydromorphic Ferrohumiluvic Spodosol. P2: Typical Orthic Ferrohumiluvic Spodosol. P3: Typical Hydromorphic Ferroluvic Spodosol. P4: Arenic Orthic Ferroluvic Spodosol.
Resumo:
Among the soils in the Mato Grosso do Sul, stand out in the Pantanal biome, the Spodosols. Despite being recorded in considerable extensions, few studies aiming to characterize and classify these soils were performed. The purpose of this study was to characterize and classify soils in three areas of two physiographic types in the Taquari river basin: bay and flooded fields. Two trenches were opened in the bay area (P1 and P2) and two in the flooded field (P3 and P4). The third area (saline) with high sodium levels was sampled for further studies. In the soils in both areas the sand fraction was predominant and the texture from sand to sandy loam, with the main constituent quartz. In the bay area, the soil organic carbon in the surface layer (P1) was (OC) > 80 g kg-1, being diagnosed as Histic epipedon. In the other profiles the surface horizons had low OC levels which, associated with other properties, classified them as Ochric epipedons. In the soils of the bay area (P1 and P2), the pH ranged from 5.0 to 7.5, associated with dominance of Ca2+ and Mg2+, with base saturation above 50 % in some horizons. In the flooded fields (P3 and P4) the soil pH ranged from 4.9 to 5.9, H+ contents were high in the surface horizons (0.8-10.5 cmol c kg-1 ), Ca2+ and Mg² contents ranged from 0.4 to 0.8 cmol c kg-1 and base saturation was < 50 %. In the soils of the bay area (P1 and P2) iron was accumulated (extracted by dithionite - Fed) and OC in the spodic horizon; in the P3 and P4 soils only Fed was accumulated (in the subsurface layers). According to the criteria adopted by the Brazilian System of Soil Classification (SiBCS) at the subgroup level, the soils were classified as: P1: Organic Hydromorphic Ferrohumiluvic Spodosol. P2: Typical Orthic Ferrohumiluvic Spodosol. P3: Typical Hydromorphic Ferroluvic Spodosol. P4: Arenic Orthic Ferroluvic Spodosol.
Resumo:
Il presente lavoro è motivato dal problema della constituzione di unità percettive a livello della corteccia visiva primaria V1. Si studia dettagliatamente il modello geometrico di Citti-Sarti con particolare attenzione alla modellazione di fenomeni di associazione visiva. Viene studiato nel dettaglio un modello di connettività. Il contributo originale risiede nell'adattamento del metodo delle diffusion maps, recentemente introdotto da Coifman e Lafon, alla geometria subriemanniana della corteccia visiva. Vengono utilizzati strumenti di teoria del potenziale, teoria spettrale, analisi armonica in gruppi di Lie per l'approssimazione delle autofunzioni dell'operatore del calore sul gruppo dei moti rigidi del piano. Le autofunzioni sono utilizzate per l'estrazione di unità percettive nello stimolo visivo. Sono presentate prove sperimentali e originali delle capacità performanti del metodo.
Resumo:
A conceptual scheme for the transition from winter to spring is developed for a small Arctic estuary (Churchill River, Hudson Bay) using hydrological, meteorological and oceanographic data together with models of the landfast ice. Observations within the Churchill River estuary and away from the direct influence of the river plume (Button Bay), between March and May 2005, show that both sea ice (production and melt) and river water influence the region's freshwater budget. In Button Bay, ice production in the flaw lead or polynya of NW Hudson Bay result in salinization through winter until the end of March, followed by a gradual freshening of the water column through April-May. In the Churchill Estuary, conditions varied abruptly throughout winter-spring depending on the physical interaction among river discharge, the seasonal landfast ice, and the rubble zone along the seaward margin of the landfast ice. Until late May, the rubble zone partially impounded river discharge, influencing the surface salinity, stratification, flushing time, and distribution and abundance of nutrients in the estuary. The river discharge, in turn, advanced and enhanced sea ice ablation in the estuary by delivering sensible heat. Weak stratification, the supply of riverine nitrogen and silicate, and a relatively long flushing time (~6 days) in the period preceding melt may have briefly favoured phytoplankton production in the estuary when conditions were still poor in the surrounding coastal environment. However, in late May, the peak flow and breakdown of the ice-rubble zone around the estuary brought abrupt changes, including increased stratification and turbidity, reduced marine and freshwater nutrient supply, a shorter flushing time, and the release of the freshwater pool into the interior ocean. These conditions suppressed phytoplankton productivity while enhancing the inventory of particulate organic matter delivered by the river. The physical and biological changes observed in this study highlight the variability and instability of small frozen estuaries during winter-spring transition, which implies sensitivity to climate change.
Resumo:
The spatial and temporal dynamics of seagrasses have been studied from the leaf to patch (100 m**2) scales. However, landscape scale (> 100 km**2) seagrass population dynamics are unresolved in seagrass ecology. Previous remote sensing approaches have lacked the temporal or spatial resolution, or ecologically appropriate mapping, to fully address this issue. This paper presents a robust, semi-automated object-based image analysis approach for mapping dominant seagrass species, percentage cover and above ground biomass using a time series of field data and coincident high spatial resolution satellite imagery. The study area was a 142 km**2 shallow, clear water seagrass habitat (the Eastern Banks, Moreton Bay, Australia). Nine data sets acquired between 2004 and 2013 were used to create seagrass species and percentage cover maps through the integration of seagrass photo transect field data, and atmospherically and geometrically corrected high spatial resolution satellite image data (WorldView-2, IKONOS and Quickbird-2) using an object based image analysis approach. Biomass maps were derived using empirical models trained with in-situ above ground biomass data per seagrass species. Maps and summary plots identified inter- and intra-annual variation of seagrass species composition, percentage cover level and above ground biomass. The methods provide a rigorous approach for field and image data collection and pre-processing, a semi-automated approach to extract seagrass species and cover maps and assess accuracy, and the subsequent empirical modelling of seagrass biomass. The resultant maps provide a fundamental data set for understanding landscape scale seagrass dynamics in a shallow water environment. Our findings provide proof of concept for the use of time-series analysis of remotely sensed seagrass products for use in seagrass ecology and management.
Resumo:
La vulnerabilidad de los sistemas ganaderos de pastoreo pone en evidencia la necesidad de herramientas para evaluar y mitigar los efectos de la sequía. El avance en la teledetección ha despertado el interés por explotar potenciales aplicaciones, y está dando lugar a un intenso desarrollo de innovaciones en distintos campos. Una de estas áreas es la gestión del riesgo climático, en donde la utilización de índices de vegetación permite la evaluación de la sequía. En esta investigación, se analiza el impacto de la sequía y se evalúa el potencial de nuevas tecnologías como la teledetección para la gestión del riesgo de sequía en sistemas de ganadería extensiva. Para ello, se desarrollan tres aplicaciones: (i) evaluar el impacto económico de la sequía en una explotación ganadera extensiva de la dehesa de Andalucía, (ii) elaborar mapas de vulnerabilidad a la sequía en pastos de Chile y (iii) diseñar y evaluar el potencial de un seguro indexado para sequía en pastos en la región de Coquimbo en Chile. En la primera aplicación, se diseña un modelo dinámico y estocástico que integra aspectos climáticos, ecológicos, agronómicos y socioeconómicos para evaluar el riesgo de sequía. El modelo simula una explotación ganadera tipo de la dehesa de Andalucía para el período 1999-2010. El método de Análisis Histórico y la simulación de MonteCarlo se utilizan para identificar los principales factores de riesgo de la explotación, entre los que destacan, los periodos de inicios del verano e inicios de invierno. Los resultados muestran la existencia de un desfase temporal entre el riesgo climático y riesgo económico, teniendo este último un periodo de duración más extenso en el tiempo. También, revelan que la intensidad, frecuencia y duración son tres atributos cruciales que determinan el impacto económico de la sequía. La estrategia de reducción de la carga ganadera permite aminorar el riesgo, pero conlleva una disminución en el margen bruto de la explotación. La segunda aplicación está dedicada a la elaboración de mapas de vulnerabilidad a la sequia en pastos de Chile. Para ello, se propone y desarrolla un índice de riesgo económico (IRESP) sencillo de interpretar y replicable, que integra factores de riesgo y estrategias de adaptación para obtener una medida del Valor en Riesgo, es decir, la máxima pérdida esperada en un año con un nivel de significación del 5%.La representación espacial del IRESP pone en evidencia patrones espaciales y diferencias significativas en la vulnerabilidad a la sequía a lo largo de Chile. Además, refleja que la vulnerabilidad no siempre esta correlacionada con el riesgo climático y demuestra la importancia de considerar las estrategias de adaptación. Las medidas de autocorrelación espacial revelan que el riesgo sistémico es considerablemente mayor en el sur que en el resto de zonas. Los resultados demuestran que el IRESP transmite información pertinente y, que los mapas de vulnerabilidad pueden ser una herramienta útil en el diseño de políticas y toma de decisiones para la gestión del riesgo de sequía. La tercera aplicación evalúa el potencial de un seguro indexado para sequía en pastos en la región de Coquimbo en Chile. Para lo cual, se desarrolla un modelo estocástico para estimar la prima actuarialmente justa del seguro y se proponen y evalúan pautas alternativas para mejorar el diseño del contrato. Se aborda el riesgo base, el principal problema de los seguros indexados identificado en la literatura y, que está referido a la correlación imperfecta del índice con las pérdidas de la explotación. Para ello, se sigue un enfoque bayesiano que permite evaluar el impacto en el riesgo base de las pautas de diseño propuestas: i) una zonificación por clúster que considera aspectos espacio-temporales, ii) un período de garantía acotado a los ciclos fenológicos del pasto y iii) umbral de garantía. Los resultados muestran que tanto la zonificación como el periodo de garantía reducen el riesgo base considerablemente. Sin embargo, el umbral de garantía tiene un efecto ambiguo sobre el riesgo base. Por otra parte, la zonificación por clúster contribuye a aminorar el riesgo sistémico que enfrentan las aseguradoras. Estos resultados han puesto de manifiesto que un buen diseño de contrato puede tener un doble dividendo, por un lado aumentar su utilidad y, por otro, reducir el coste del seguro. Un diseño de contrato eficiente junto con los avances en la teledetección y un adecuado marco institucional son los pilares básicos para el buen funcionamiento de un programa de seguro. Las nuevas tecnologías ofrecen un importante potencial para la innovación en la gestión del riesgo climático. Los avances en este campo pueden proporcionar importantes beneficios sociales en los países en desarrollo y regiones vulnerables, donde las herramientas para gestionar eficazmente los riesgos sistémicos como la sequía pueden ser de gran ayuda para el desarrollo. The vulnerability of grazing livestock systems highlights the need for tools to assess and mitigate the adverse impact of drought. The recent and rapid progress in remote sensing has awakened an interest for tapping into potential applications, triggering intensive efforts to develop innovations in a number of spheres. One of these areas is climate risk management, where the use of vegetation indices facilitates assessment of drought. This research analyzes drought impacts and evaluates the potential of new technologies such as remote sensing to manage drought risk in extensive livestock systems. Three essays in drought risk management are developed to: (i) assess the economic impact of drought on a livestock farm in the Andalusian Dehesa, (ii) build drought vulnerability maps in Chilean grazing lands, and (iii) design and evaluate the potential of an index insurance policy to address the risk of drought in grazing lands in Coquimbo, Chile. In the first essay, a dynamic and stochastic farm model is designed combining climate, agronomic, socio-economic and ecological aspects to assess drought risk. The model is developed to simulate a representative livestock farm in the Dehesa of Andalusia for the time period 1999-2010. Burn analysis and MonteCarlo simulation methods are used to identify the significance of various risk sources at the farm. Most notably, early summer and early winter are identified as periods of peak risk. Moreover, there is a significant time lag between climate and economic risk and this later last longer than the former. It is shown that intensity, frequency and duration of the drought are three crucial attributes that shape the economic impact of drought. Sensitivity analysis is conducted to assess the sustainability of farm management strategies and demonstrates that lowering the stocking rate reduces farmer exposure to drought risk but entails a reduction in the expected gross margin. The second essay, mapping drought vulnerability in Chilean grazing lands, proposes and builds an index of economic risk (IRESP) that is replicable and simple to interpret. This methodology integrates risk factors and adaptation strategies to deliver information on Value at Risk, maximum expected losses at 5% significance level. Mapping IRESP provides evidence about spatial patterns and significant differences in drought vulnerability across Chilean grazing lands. Spatial autocorrelation measures reveal that systemic risk is considerably larger in the South as compared to Northern or Central Regions. Furthermore, it is shown that vulnerability is not necessarily correlated with climate risk and that adaptation strategies do matter. These results show that IRESP conveys relevant information and that vulnerability maps may be useful tools to assess policy design and decision-making in drought risk management. The third essay develops a stochastic model to estimate the actuarially fair premium and evaluates the potential of an indexed insurance policy to manage drought risk in Coquimbo, a relevant livestock farming region of Chile. Basis risk refers to the imperfect correlation of the index and farmer loses and is identified in the literature as a main limitation of index insurance. A Bayesian approach is proposed to assess the impact on basis risk of alternative guidelines in contract design: i) A cluster zoning that considers space-time aspects, ii) A guarantee period bounded to fit phenological cycles, and iii) the triggering index threshold. Results show that both the proposed zoning and guarantee period considerably reduces basis risk. However, the triggering index threshold has an ambiguous effect on basis risk. On the other hand, cluster zoning contributes to ameliorate systemic risk faced by the insurer. These results highlighted that adequate contract design is important and may result in double dividend. On the one hand, increasing farmers’ utility and, secondly, reducing the cost of insurance. An efficient contract design coupled with advances in remote sensing and an appropriate institutional framework are the basis for an efficient operation of an insurance program. The new technologies offer significant potential for innovation in climate risk managements. Progress in this field is capturing increasing attention and may provide important social gains in developing countries and vulnerable regions where the tools to efficiently manage systemic risks, such as drought, may be a means to foster development.
Resumo:
This layer is a georeferenced raster image of the historic paper map entitled: A map of the West-Indies or the islands of America in the North Sea : with ye adjacent countries, explaning [sic] what belongs to Spain, England, France, Holland &c. also ye trade winds, and ye several tracts made by ye galeons and flota from place to place : according to ye newest and most exact observations, by Herman Moll, geographer. It was printed for Tho. Bowles in St. Pauls Church Yard and John Bowles at the Black Horse in Cornhill ca. 1715. Scale [ca. 1:4,300,000]. Covers the Gulf of Mexico and Caribbean Sea Region including parts of southern United States, Mexico, Central America, West Indies, and northern South America.The image inside the map neatline is georeferenced to the surface of the earth and fit to the North American Lambert Conformal Conic coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, territorial boundaries, shoreline features, and more. Relief shown pictorially. Includes also historical notes and insets.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.
Resumo:
This layer is a georeferenced raster image of the historic paper map entitled: Carte réduite de la mer Méditerranée et de la mer Noire : dédiée et présentée a S.A.R. M. le duc d'Angoulême..., par P. Lapie, géographe, Directeur du Cabinet topographique du Roi ; gravé par P.A.F. Tardieu. It was published by Rey et Gravier, libraires Quai des Augustins, no. 55 in 1814. Scale [ca. 1:35,500]. Covers Mediterranean Sea, Black Sea, and coasts of Europe, North Africa, and the Middle East. Map in French. The image inside the map neatline is georeferenced to the surface of the earth and fit to the World Miller Cylindrical projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as drainage, cities and other human settlements, shoreline features, and more. Relief shown pictorially. Depths shown by soundings. Includes also inset map of the Sea of Azov.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.