Applications for wireless sensor networks : tracking with binary proximity sensors

El interés cada vez mayor por las redes de sensores inalámbricos pueden ser entendido simplemente pensando en lo que esencialmente son: un gran número de pequeños nodos sensores autoalimentados que recogen información o detectan eventos especiales y se comunican de manera inalámbrica, con el objetivo final de entregar sus datos procesados a una estación base. Los nodos sensores están densamente desplegados dentro del área de interés, se pueden desplegar al azar y tienen capacidad de cooperación. Por lo general, estos dispositivos son pequeños y de bajo costo, de modo que pueden ser producidos y desplegados en gran numero aunque sus recursos en términos de energía, memoria, velocidad de cálculo y ancho de banda están enormemente limitados. Detección, tratamiento y comunicación son tres elementos clave cuya combinación en un pequeño dispositivo permite lograr un gran número de aplicaciones. Las redes de sensores proporcionan oportunidades sin fin, pero al mismo tiempo plantean retos formidables, tales como lograr el máximo rendimiento de una energía que es escasa y por lo general un recurso no renovable. Sin embargo, los recientes avances en la integración a gran escala, integrado de hardware de computación, comunicaciones, y en general, la convergencia de la informática y las comunicaciones, están haciendo de esta tecnología emergente una realidad. Del mismo modo, los avances en la nanotecnología están empezando a hacer que todo gire entorno a las redes de pequeños sensores y actuadores distribuidos. Hay diferentes tipos de sensores tales como sensores de presión, acelerómetros, cámaras, sensores térmicos o un simple micrófono. Supervisan las condiciones presentes en diferentes lugares tales como la temperatura, humedad, el movimiento, la luminosidad, presión, composición del suelo, los niveles de ruido, la presencia o ausencia de ciertos tipos de objetos, los niveles de tensión mecánica sobre objetos adheridos y las características momentáneas tales como la velocidad , la dirección y el tamaño de un objeto, etc. Se comprobara el estado de las Redes Inalámbricas de Sensores y se revisaran los protocolos más famosos. Así mismo, se examinara la identificación por radiofrecuencia (RFID) ya que se está convirtiendo en algo actual y su presencia importante. La RFID tiene un papel crucial que desempeñar en el futuro en el mundo de los negocios y los individuos por igual. El impacto mundial que ha tenido la identificación sin cables está ejerciendo fuertes presiones en la tecnología RFID, los servicios de investigación y desarrollo, desarrollo de normas, el cumplimiento de la seguridad y la privacidad y muchos más. Su potencial económico se ha demostrado en algunos países mientras que otros están simplemente en etapas de planificación o en etapas piloto, pero aun tiene que afianzarse o desarrollarse a través de la modernización de los modelos de negocio y aplicaciones para poder tener un mayor impacto en la sociedad. Las posibles aplicaciones de redes de sensores son de interés para la mayoría de campos. La monitorización ambiental, la guerra, la educación infantil, la vigilancia, la micro-cirugía y la agricultura son solo unos pocos ejemplos de los muchísimos campos en los que tienen cabida las redes mencionadas anteriormente. Estados Unidos de América es probablemente el país que más ha investigado en esta área por lo que veremos muchas soluciones propuestas provenientes de ese país. Universidades como Berkeley, UCLA (Universidad de California, Los Ángeles) Harvard y empresas como Intel lideran dichas investigaciones. Pero no solo EE.UU. usa e investiga las redes de sensores inalámbricos. La Universidad de Southampton, por ejemplo, está desarrollando una tecnología para monitorear el comportamiento de los glaciares mediante redes de sensores que contribuyen a la investigación fundamental en glaciología y de las redes de sensores inalámbricos. Así mismo, Coalesenses GmbH (Alemania) y Zurich ETH están trabajando en diversas aplicaciones para redes de sensores inalámbricos en numerosas áreas. Una solución española será la elegida para ser examinada más a fondo por ser innovadora, adaptable y polivalente. Este estudio del sensor se ha centrado principalmente en aplicaciones de tráfico, pero no se puede olvidar la lista de más de 50 aplicaciones diferentes que ha sido publicada por la firma creadora de este sensor específico. En la actualidad hay muchas tecnologías de vigilancia de vehículos, incluidos los sensores de bucle, cámaras de video, sensores de imagen, sensores infrarrojos, radares de microondas, GPS, etc. El rendimiento es aceptable, pero no suficiente, debido a su limitada cobertura y caros costos de implementación y mantenimiento, especialmente este ultimo. Tienen defectos tales como: línea de visión, baja exactitud, dependen mucho del ambiente y del clima, no se puede realizar trabajos de mantenimiento sin interrumpir las mediciones, la noche puede condicionar muchos de ellos, tienen altos costos de instalación y mantenimiento, etc. Por consiguiente, en las aplicaciones reales de circulación, los datos recibidos son insuficientes o malos en términos de tiempo real debido al escaso número de detectores y su costo. Con el aumento de vehículos en las redes viales urbanas las tecnologías de detección de vehículos se enfrentan a nuevas exigencias. Las redes de sensores inalámbricos son actualmente una de las tecnologías más avanzadas y una revolución en la detección de información remota y en las aplicaciones de recogida. Las perspectivas de aplicación en el sistema inteligente de transporte son muy amplias. Con este fin se ha desarrollado un programa de localización de objetivos y recuento utilizando una red de sensores binarios. Esto permite que el sensor necesite mucha menos energía durante la transmisión de información y que los dispositivos sean más independientes con el fin de tener un mejor control de tráfico. La aplicación se centra en la eficacia de la colaboración de los sensores en el seguimiento más que en los protocolos de comunicación utilizados por los nodos sensores. Las operaciones de salida y retorno en las vacaciones son un buen ejemplo de por qué es necesario llevar la cuenta de los coches en las carreteras. Para ello se ha desarrollado una simulación en Matlab con el objetivo localizar objetivos y contarlos con una red de sensores binarios. Dicho programa se podría implementar en el sensor que Libelium, la empresa creadora del sensor que se examinara concienzudamente, ha desarrollado. Esto permitiría que el aparato necesitase mucha menos energía durante la transmisión de información y los dispositivos sean más independientes. Los prometedores resultados obtenidos indican que los sensores de proximidad binarios pueden formar la base de una arquitectura robusta para la vigilancia de áreas amplias y para el seguimiento de objetivos. Cuando el movimiento de dichos objetivos es suficientemente suave, no tiene cambios bruscos de trayectoria, el algoritmo ClusterTrack proporciona un rendimiento excelente en términos de identificación y seguimiento de trayectorias los objetos designados como blancos. Este algoritmo podría, por supuesto, ser utilizado para numerosas aplicaciones y se podría seguir esta línea de trabajo para futuras investigaciones. No es sorprendente que las redes de sensores de binarios de proximidad hayan atraído mucha atención últimamente ya que, a pesar de la información mínima de un sensor de proximidad binario proporciona, las redes de este tipo pueden realizar un seguimiento de todo tipo de objetivos con la precisión suficiente. Abstract The increasing interest in wireless sensor networks can be promptly understood simply by thinking about what they essentially are: a large number of small sensing self-powered nodes which gather information or detect special events and communicate in a wireless fashion, with the end goal of handing their processed data to a base station. The sensor nodes are densely deployed inside the phenomenon, they deploy random and have cooperative capabilities. Usually these devices are small and inexpensive, so that they can be produced and deployed in large numbers, and so their resources in terms of energy, memory, computational speed and bandwidth are severely constrained. Sensing, processing and communication are three key elements whose combination in one tiny device gives rise to a vast number of applications. Sensor networks provide endless opportunities, but at the same time pose formidable challenges, such as the fact that energy is a scarce and usually non-renewable resource. However, recent advances in low power Very Large Scale Integration, embedded computing, communication hardware, and in general, the convergence of computing and communications, are making this emerging technology a reality. Likewise, advances in nanotechnology and Micro Electro-Mechanical Systems are pushing toward networks of tiny distributed sensors and actuators. There are different sensors such as pressure, accelerometer, camera, thermal, and microphone. They monitor conditions at different locations, such as temperature, humidity, vehicular movement, lightning condition, pressure, soil makeup, noise levels, the presence or absence of certain kinds of objects, mechanical stress levels on attached objects, the current characteristics such as speed, direction and size of an object, etc. The state of Wireless Sensor Networks will be checked and the most famous protocols reviewed. As Radio Frequency Identification (RFID) is becoming extremely present and important nowadays, it will be examined as well. RFID has a crucial role to play in business and for individuals alike going forward. The impact of ‘wireless’ identification is exerting strong pressures in RFID technology and services research and development, standards development, security compliance and privacy, and many more. The economic value is proven in some countries while others are just on the verge of planning or in pilot stages, but the wider spread of usage has yet to take hold or unfold through the modernisation of business models and applications. Possible applications of sensor networks are of interest to the most diverse fields. Environmental monitoring, warfare, child education, surveillance, micro-surgery, and agriculture are only a few examples. Some real hardware applications in the United States of America will be checked as it is probably the country that has investigated most in this area. Universities like Berkeley, UCLA (University of California, Los Angeles) Harvard and enterprises such as Intel are leading those investigations. But not just USA has been using and investigating wireless sensor networks. University of Southampton e.g. is to develop technology to monitor glacier behaviour using sensor networks contributing to fundamental research in glaciology and wireless sensor networks. Coalesenses GmbH (Germany) and ETH Zurich are working in applying wireless sensor networks in many different areas too. A Spanish solution will be the one examined more thoroughly for being innovative, adaptable and multipurpose. This study of the sensor has been focused mainly to traffic applications but it cannot be forgotten the more than 50 different application compilation that has been published by this specific sensor’s firm. Currently there are many vehicle surveillance technologies including loop sensors, video cameras, image sensors, infrared sensors, microwave radar, GPS, etc. The performance is acceptable but not sufficient because of their limited coverage and expensive costs of implementation and maintenance, specially the last one. They have defects such as: line-ofsight, low exactness, depending on environment and weather, cannot perform no-stop work whether daytime or night, high costs for installation and maintenance, etc. Consequently, in actual traffic applications the received data is insufficient or bad in terms of real-time owed to detector quantity and cost. With the increase of vehicle in urban road networks, the vehicle detection technologies are confronted with new requirements. Wireless sensor network is the state of the art technology and a revolution in remote information sensing and collection applications. It has broad prospect of application in intelligent transportation system. An application for target tracking and counting using a network of binary sensors has been developed. This would allow the appliance to spend much less energy when transmitting information and to make more independent devices in order to have a better traffic control. The application is focused on the efficacy of collaborative tracking rather than on the communication protocols used by the sensor nodes. Holiday crowds are a good case in which it is necessary to keep count of the cars on the roads. To this end a Matlab simulation has been produced for target tracking and counting using a network of binary sensors that e.g. could be implemented in Libelium’s solution. Libelium is the enterprise that has developed the sensor that will be deeply examined. This would allow the appliance to spend much less energy when transmitting information and to make more independent devices. The promising results obtained indicate that binary proximity sensors can form the basis for a robust architecture for wide area surveillance and tracking. When the target paths are smooth enough ClusterTrack particle filter algorithm gives excellent performance in terms of identifying and tracking different target trajectories. This algorithm could, of course, be used for different applications and that could be done in future researches. It is not surprising that binary proximity sensor networks have attracted a lot of attention lately. Despite the minimal information a binary proximity sensor provides, networks of these sensing modalities can track all kinds of different targets classes accurate enough.

Publication /

Each no. has also a distinctive title.

700 Mev negative hydrogen ion cyclotron facility.

"Contract AEC at (11-1) 34 Project 93, April 1963."

Colloquium documents - Interdisciplinary Colloquium on Mathematics in the Behavioral Sciences.

Mode of access: Internet.

Employee discipline /

"Developed under contract to the State of California Agriculture and Services Agency through a grant from the U.S. Civil Service Commission under the Intergovernmental Personnel Act (P.L. 91-648)."--verso of t.p.

Qualidade Subjetiva do Sono, Sintomas Depressivos e Sentimentos de Solidão em Idosos Institucionalizados e Não Institucionalizados

Parece existir uma associação entre solidão e uma pobre qualidade subjetiva do sono. Em reforço desta ideia, alguns estudos mostraram que os sentimentos de solidão se associam a uma menor satisfação do sono, mesmo que a sua duração não esteja diminuída. Outros mostraram que a solidão se associa a sintomas depressivos. Sabe-se que na institucionalização são frequentes os problemas de sono, depressão e solidão. No entanto, falta saber o que se passa nas respostas sociais portuguesas. Assim foram os nossos principais objetivos descrever a qualidade subjetiva do sono e analisar a intensidade dos sintomas depressivos e dos sintomas de solidão em idosos institucionalizados, comparar com uma subamostra de idosos não institucionalizados e analisar a relação entre estas variáveis nas duas subamostras. Cento e quarenta idosos, com 70 institucionalizados e 70 não institucionalizados foram emparelhados por idade, sexo, escolaridade, estado civil e sem défice cognitivo. A média de idades foi de 76,58 (DP = 6,10), sendo 104 mulheres e 36 homens. Como instrumentos para a análise utilizámos um Questionário Sociodemográfico, o Questionário sobre o Sono na Terceira Idade, o Inventário de Depressão Geriátrica e a Escala de Solidão da Universidade da Califórnia, Los Angeles. Verificou-se que os idosos institucionalizados apresentavam mais sentimentos de solidão do que os não institucionalizados. Contudo, não se verificaram diferenças entre as duas subamostras em relação aos sintomas depressivos e à qualidade subjetiva do sono. Através de uma análise correlacional verificou-se nas duas subamostras que quanto pior a qualidade subjetiva do sono mais sintomas depressivos se observavam e quanto mais sintomas depressivos, mais sentimentos de solidão. Concluímos que não houve diferenças na qualidade subjetiva do sono pelo tipo de resposta social ainda que haja mais sintomas depressivos e sintomas de solidão nos idosos institucionalizados. Não encontrámos também relação entre o sono e a solidão nos idosos institucionalizados. / There seems to be an association between loneliness and poor subjective sleep quality. In support of this idea, some studies have shown that feelings of loneliness are associated with less satisfaction sleep, even if your life is not diminished. Others have shown that loneliness is associated with depressive symptoms. It is known that in the institutionalization are frequent problems with sleeping, depression and loneliness. However, lack know what is happening in the Portuguese social responses. So were our main objectives describe the subjective quality of sleep and analyze the intensity of depressive symptoms and loneliness symptoms in institutionalized elderly, compared with a non-institutionalized elderly subsample and analyze the relationship between these variables in both subsamples. One hundred and forty older adults, with 70 institutionalized and 70 non-institutionalized were matched by age, sex, education, marital status and without cognitive impairment. The average age was 76.58 (SD = 6.10), including 104 women and 36 men. As tools for the analysis we used a sociodemographic questionnaire, the Questionnaire About Sleep in the Older Adults, Geriatric Depression Inventory and the Loneliness Scale of the University of California, Los Angeles. It was found that the institutionalized older adults had more feelings of loneliness than noninstitutionalized. However, there were no differences between the two subsamples in relation to depressive symptoms and subjective sleep quality. Through a correlational analysis it was found in the two subsamples that the worse the subjective sleep quality more depressive symptoms were observed and the more depressive symptoms, more feelings of loneliness. We concluded that there no differences in subjective sleep quality by the type of social response even though there are more depressive symptoms and symptoms of loneliness in the elderly. Also we did not find relationship between sleep and loneliness in the elderly.

Qualidade subjetiva do sono, sintomas depressivos, sentimentos de solidão e institucionalização em pessoas idosas

RESUMO Objetivos: A presente investigação teve como principais objetivos descrever a qualidade subjetiva do sono e as perturbações do sono e analisar a intensidade dos sintomas depressivos e dos sentimentos de solidão em idosos institucionalizados; comparar estes dados com um grupo de idosos não institucionalizados e analisar a relação entre estas variáveis nos dois grupos. Métodos: Este estudo insere-se no Projeto Trajetórias do Envelhecimento de Idosos em Resposta Social de onde foi retirada uma amostra de cento e quarenta idosos sem défice cognitivo, com 70 institucionalizados e 70 não institucionalizados emparelhados por idade, sexo, escolaridade e estado civil. A média de idades foi de 76,58 (DP = 6,10), incluindo 104 mulheres e 36 homens. Como instrumentos foram utilizados um Questionário Sociodemográfico, o Questionário sobre o Sono na Terceira Idade, a Escala Geriátrica de depressão e a Escala de Solidão da Universidade da Califórnia, Los Angeles. Resultados: Verificou-se que os idosos institucionalizados apresentavam mais sentimentos de solidão do que os não institucionalizados. Contudo, não se verificaram diferenças entre os dois grupos em relação aos sintomas depressivos, qualidade subjetiva do sono ou perturbações do sono, com algumas exceções: os idosos residentes na comunidade mostraram ter a perceção de demorar mais tempo a adormecer, de acordar mais cedo e de ter mais pesadelos. Através de uma análise correlacional verificou-se, na amostra global, que quanto pior a qualidade subjetiva do sono mais sintomas depressivos se observavam e quanto mais sintomas depressivos, mais sentimentos de solidão, não havendo, contudo, relação entre o sono e a solidão. Conclusões: Concluímos que a situação de institucionalização se acompanha de mais sentimentos de solidão, mas não de sintomas depressivos ou de pior qualidade de sono. Por esse motivo, sugere-se que se desenvolvam programas de intervenção dirigidos à solidão em idosos institucionalizados. ABSTRACT Aims: The main objectives of this investigation were to describe the subjective quality of sleep and sleep disorders and analyze the intensity of depressive and loneliness symptoms in institutionalized elderly people; compare these data against a non-institutionalized elderly people subsample and analyze the relationship between these variables in both subsamples. Method: This study is part of Trajectories of Elderly Aging in Social Response Project from which a sample of one hundred and forty elderly people with no cognitive impairment was taken, with 70 institutionalized and 70 non-institutionalized matched by age, sex, education, and marital status. The average age was 76.58 (SD = 6.10), including 104 women and 36 men. The tools used for this analysis were a sociodemographic questionnaire, the Questionnaire About Sleep in the Older Adults, Geriatric Depression Scale, and the Loneliness Scale of the University of California, Los Angeles. Results: The study confirmed that institutionalized elderly people had more feelings of loneliness than those non-institutionalized. However, there were no differences between the two subsamples regarding depressive symptoms and subjective sleep quality or sleep disturbances, with some exceptions: Elderly people living in the community showed to have the perception of taking more time to fall asleep, waking up earlier, and having more nightmares. Through a correlational analysis it was found, in both subsamples, that the worse the subjective sleep quality the more depressive symptoms were observed; and the more depressive symptoms, the more feelings of loneliness, despite of not existing a relation between sleep and loneliness. Conclusions: We concluded that institutionalization is linked to more feelings of loneliness but not to depressive symptoms nor to worse quality of sleep. For this reason, it is suggested that intervention programs are developed with a focus on elderly institutionalized populations.

Displaying and celebrating the "other": A study of the mission, scope, and roles of ethnic museums in Los Angeles

In the last thirty years, ethnic museums have mushroomed in American cities. Although this is certainly a national phenomenon, it has been particularly evident in Los Angeles. In this paper we examine the genesis and evolution of these emerging institutions. We survey the mission, scope, and role of ethnic museums in Los Angeles, and we contrast them with the stated mission and scope of “mainstream” museums in the city. We further present case studies of three Los Angeles ethnic museums. The museums vary considerably in the ways they perceive their role in the community, the city, and the nation and in the preservation and display of ethnic culture. At their best, ethnic museums serve to make new art and histories more accessible and visible and provide a forum in which to debate contemporary issues of politics and identity. The paper highlights some of the tensions faced by ethnic museums as they seek to define their audience and role(s) in multi-ethnic, twenty-first century Los Angeles.

I. Foehn winds of southern California. II. Foehn wind cyclo-genesis. III. Weather conditions associated with the Akron disaster. IV. The Los Angeles storm of December 30, 1933 to January 1, 1934

I. Foehn winds of southern California.
An investigation of the hot, dry and dust laden winds occurring in the late fall and early winter in the Los Angeles Basin and attributed in the past to the influences of the desert regions to the north revealed that these currents were of a foehn nature. Their properties were found to be entirely due to dynamical heating produced in the descent from the high level areas in the interior to the lower Los Angeles Basin. Any dust associated with the phenomenon was found to be acquired from the Los Angeles area rather than transported from the desert. It was found that the frequency of occurrence of a mild type foehn of this nature during this season was sufficient to warrant its classification as a winter monsoon. This results from the topography of the Los Angeles region which allows an easy entrance to the air from the interior by virtue of the low level mountain passes north of the area. This monsoon provides the mild winter climate of southern California since temperatures associated with the foehn currents are far higher than those experienced when maritime air from the adjacent Pacific Ocean occupies the region.

II. Foehn wind cyclo-genesis.
Intense anticyclones frequently build up over the high level regions of the Great Basin and Columbia Plateau which lie between the Sierra Nevada and Cascade Mountains to the west and the Rocky Mountains to the east. The outflow from these anticyclones produce extensive foehns east of the Rockies in the comparatively low level areas of the middle west and the Canadian provinces of Alberta and Saskatchewan. Normally at this season of the year very cold polar continental air masses are present over this territory and with the occurrence of these foehns marked discontinuity surfaces arise between the warm foehn current, which is obliged to slide over a colder mass, and the Pc air to the east. Cyclones are easily produced from this phenomenon and take the form of unstable waves which propagate along the discontinuity surface between the two dissimilar masses. A continual series of such cyclones was found to occur as long as the Great Basin anticyclone is maintained with undiminished intensity.

III. Weather conditions associated with the Akron disaster.
This situation illustrates the speedy development and propagation of young disturbances in the eastern United States during the spring of the year under the influence of the conditionally unstable tropical maritime air masses which characterise the region. It also furnishes an excellent example of the superiority of air mass and frontal methods of weather prediction for aircraft operation over the older methods based upon pressure distribution.

IV. The Los Angeles storm of December 30, 1933 to January 1, 1934.
This discussion points out some of the fundamental interactions occurring between air masses of the North Pacific Ocean in connection with Pacific Coast storms and the value of topographic and aerological considerations in predicting them. Estimates of rainfall intensity and duration from analyses of this type may be made and would prove very valuable in the Los Angeles area in connection with flood control problems.

Los Angeles, California (East), and vicinity, 1953 (Raster Image) (Image 1 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheep map set entitled: Los Angeles and vicinity, East [and West], California. Edition 1953. It was published in 1956. Compiled from 1:24,000 scale maps of the Azusa 1953, Mt. Wilson 1953, Pasadena 1953, Los Angeles 1953, El Monte 1953, Baldwin Park 1953, La Habra 1950, Whittier 1949, and South Gate 1952 7.5 minute quadrangles. Scale 1:24,000. This layer is image 1 of 2 total images of the two sheet source map set representing the eastern portion of the map set. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California State Plane Zone V Coordinate System NAD27 (in Feet) (Fipszone 0405). 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. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 5 and 25 feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Los Angeles, California (West), and vicinity, 1953 (Raster Image) (Image 2 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheep map set entitled: Los Angeles and vicinity, East [and West], California. Edition 1953. It was published in 1956. Compiled from 1:24,000 scale maps of the Burbank 1953, Van Nuys 1953, Canoga Park 1952, Topanga 1952, Beverly Hills 1950, Hollywood 1953, Inglewood 1952, and Venice 1950 7.5 minute quadrangles. Hydrography compiled from USC&GS Chart 5144. Scale 1:24,000. This layer is image 2 of 2 total images of the two sheet source map set representing the western portion of the map set. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California State Plane Zone V Coordinate System NAD27 (in Feet) (Fipszone 0405). 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. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 5 and 25 feet. Depth curves in feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.