# Define options set val(chan) Channel/WirelessChannel ;# channel type set val(prop) Propagation/TwoRayGround ;# radio-propagation model set val(netif) Phy/WirelessPhy ;# network interface type set val(mac) Mac/802_11 ;# MAC type set val(ifq) Queue/DropTail/PriQueue ;# interface queue type set val(ll) LL ;# link layer type set val(ant) Antenna/OmniAntenna ;# antenna model set val(ifqlen) 50 ;# max packet in ifq set val(nn) 8 ;# number of mobilenodes set val(rp) AODV ;# routing protocol set val(x) 1200 ;# X dimension of topography set val(y) 1200 ;# Y dimension of topography set val(stop) 2 ;# time of simulation end set ns [new Simulator] set tracefd [open simple.tr w] set namtrace [open simwrls.nam w] $ns trace-all $tracefd $ns namtrace-all-wireless $namtrace $val(x) $val(y) #set different colors for data flows $ns color 0 Blue $ns color 1 Red # set up topography object set topo [new Topography] $topo load_flatgrid $val(x) $val(y) set chan_1 [new $val(chan)] create-god $val(nn) # # Create nn mobilenodes [$val(nn)] and attach them to the channel. # # configure the nodes $ns node-config -adhocRouting $val(rp) \ -llType $val(ll) \ -macType $val(mac) \ -ifqType $val(ifq) \ -ifqLen $val(ifqlen) \ -antType $val(ant) \ -propType $val(prop) \ -phyType $val(netif) \ -channel $chan_1 \ -topoInstance $topo \ -agentTrace ON \ -routerTrace ON \
The topography and bathymetry of the Earth according to the ETOPO1 model. The original model has 1 arc-minute grid spacing but here we downsampled to 0.5 degree grid spacing to save space and download times. Heights are referenced to sea level.
The Shuttle Radar Topography Mission (SRTM, see Farr et al. 2007) digital elevation data is an international research effort that obtained digital elevation models on a near-global scale. This SRTM V3 product (SRTM Plus) is provided by NASA JPL at a resolution of 1 arc-second (approximately 30m).
swissSURFACE3D光栅(DSM) 该数据集目前只对内部人员计划中的人开放。
一般有12.5m数据下载,可惜精度根本不够,比如mapbox的免费在线的,或者91卫图提供百度网盘打包下载的,没法用,差距太大。而91卫图自己使用的,精度估计是5m的,是可以的。
WRF中地形数据(海拔高度)分辨率最高为30s,差不多就是900m,当模型空间分辨率较高时,比如在低于1km的情况下,经常会考虑增加地形高度的分辨率,这里使用美国的SRTM( Shuttle Radar Topography Mission)的DEM数据,这个数据覆盖了全球陆地,在美国本地分辨率为1s,其他地区为3s(约90m),因此使用这个更高分辨率数据来测试一下。
SARAL Near-Real-Time Value-added Operational Geophysical Data Record Sea Surface Height Anomaly
ALOS World 3D - 30m (AW3D30) is a global digital surface model (DSM) dataset with a horizontal resolution of approximately 30 meters (1 arcsec mesh). The dataset is based on the DSM dataset (5-meter mesh version) of the World 3D Topographic Data. More details are available in the dataset documentation.
ETOPO1 is a 1 arc-minute global relief model of Earth's surface that integrates land topography and ocean bathymetry. It was built from numerous global and regional data sets. It contains two elevation bands: ice_surface and bedrock.
The Shuttle Radar Topography Mission (SRTM) digital elevation dataset was originally produced to provide consistent, high-quality elevation data at near global scope. This version of the SRTM digital elevation data has been processed to fill data voids, and to facilitate its ease of use.
OSM水图层 OpenStreetMap中的地表水 OSM水层是一个全球地表水数据,由OpenStreetMap中提取地表水特征生成。OSM水层栅格化地图是以WGS84为参照的。数据准备为5度x5度的瓦片(6000像素x6000像素)。文件名代表数据域的左下角像素的中心;例如,文件 "n30w120.tif "是针对域N30-N35,W120-W115。(more accurately, N29.99958333-N34.99958333,W120.0004167-W115.0004167)
空间转录组技术正在广泛应用,然而目前一些转录组的空间分析还达不到单细胞的分辨率水平。为了达到将基因表达置于空间环境中并划定组织内细胞类型空间分布的目的,来自瑞典的科研团队提出一种基于模型的概率方法:stereoscope,使用单细胞数据来解析空间数据中的细胞混合物。
SRTM数据主要是由美国航空航天局(NASA)和国防部国家测绘局(NIMA)联合测量的,SRTM的全称Shuttle Radar Topography Mission,即航天飞机雷达地形测绘使命。SRTM的数据是用16位的数值表示高程数值的,最大的正高程9000m,负高程海平面以下12000m。
The Smoothed Digital Elevation Model (DEM-S) was derived from the SRTM data acquired by NASA in February 2000. DEM-S represents ground surface topography (excluding vegetation features) and has been smoothed to reduce noise and improve the representation of surface shape. An adaptive process applied more smoothing in flatter areas than hilly areas, and more smoothing in noisier areas than in less noisy areas.
由于WRF自带最高分辨地形数据是30s的,约900m。要使用更高分辨率的地形数据需要自己制作、添加。下面简要介绍一下下载、制作和使用流程,仅供参考。
HydroSHEDS is a mapping product that provides hydrographic information for regional and global-scale applications in a consistent format. It offers a suite of geo-referenced datasets (vector and raster) at various scales, including river networks, watershed boundaries, drainage directions, and flow accumulations. HydroSHEDS is based on elevation data obtained in 2000 by NASA's Shuttle Radar Topography Mission (SRTM).
在本篇博客中,我们将使用Google Earth Engine (GEE) 对特定区域内的地形进行分析。我们将使用SRTM(Shuttle Radar Topography Mission)数据集获取高程信息,并计算坡度、坡向等地形属性。此外,我们还将使用ALOS(Advanced Land Observing Satellite)数据集来分析数字地表模型(DSM)。
NOAA海平面上升数字高程模型(DEMs) NOAA沿海服务中心已经开发了高分辨率的数字高程模型(DEMs),用于该中心的海平面上升和沿海洪水影响的互联网地图应用。这些DEMs作为源数据集,用于导出数据,以可视化美国沿海及其领土上的海平面上升造成的淹没影响。
---- 新智元报道 编辑:David 好困 【新智元导读】NASA「好奇号」火星车传回了一张照片引发网友无限脑补,有说火星人基地的、霍比特人巢穴的,还有说外星人开酒馆的,实际上到底是啥? 火星表面惊现「神秘之门」? 好奇号:「十年老车,照片保真」! 神秘墓穴?秘密基地?网友疯狂脑补 2022年5月7日,在火星上游荡了10年的好奇号传回上面的这张照片。 没过两天,国外的网友们就炸开了锅,纷纷在「瞎猜」这件事上脑洞大开。 有网友画了一张脸表示,没错,你们看到的那个像是人脸的阴影,就是外星人的脸。
GFSAD全球耕地范围产品(GCEP) NASA的 "研究环境中使用的地球系统数据记录"(MEaSUREs)全球粮食安全支持分析数据(GFSAD)数据产品以30米的分辨率提供了全球2015年的耕地范围数据。对全球耕地范围的监测对政策制定至关重要,并提供了重要的基线数据,用于许多与水的可持续性和粮食安全有关的农业耕地研究。GCEP数据产品使用基于像素的监督分类器--随机森林(RF),从Landsat 8 Operational Land Imager(OLI)、Landsat 7 Enhanced Thematic Mapper Plus(ETM+)和来自Shuttle Radar Topography Mission(SRTM)第3版数据产品的高程组合中检索出耕地范围。前言 – 床长人工智能教程
The NASA NEX-DCP30 dataset is comprised of downscaled climate scenarios for the conterminous United States that are derived from the General Circulation Model (GCM) runs conducted under the Coupled Model Intercomparison Project Phase 5 (CMIP5, see Taylor et al. 2012) and across the four greenhouse gas emissions scenarios known as Representative Concentration Pathways (RCPs, see Meinshausen et al. 2011) developed for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). The purpose of these datasets is to provide a set of high resolution, bias-corrected climate change projections that can be used to evaluate climate change impacts on processes that are sensitive to finer-scale climate gradients and the effects of local topography on climate conditions.
在这个教程中,我们将学习如何使用three.js渲染土耳其最高的Ağrı山脉的数字高程模型(DEM)数据,使用的工具包括Three.js、geotiff、webpack和QGIS。
土壤湿度是地球系统模拟的重要参数之一,准确获得其时空分布和变化特征是研究陆-气相互作用的基础。随着卫星观测技术的发展,遥感方法为土壤湿度的估算开辟了新的途径,近年来基于微波传感器的土壤湿度反演估算得到了深入研究,该技术可提供全球或区域高分辨率土壤湿度信息,已成为获取较大空间尺度土壤湿度信息的最有效手段之一。
This dataset is contains orthorectified imagery from the Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) sensor on-board the Advanced Land Observing Satellite (ALOS) "DAICHI".
Choosing Colormaps in Matplotlib Matplotlib has a number of built-in colormaps accessible via matplotlib.colormaps. There are also external libraries that have many extra colormaps, which can be viewed in the Third-party colormaps section of the Matplotlib documentation. Here we briefly discuss how to choose between the many options. For help on creating your own colormaps, see Creating Colormaps in Matplotlib.
从图中可以发现,MEG和EEG有着极好的时间分辨率,但空间分辨率很差,因此在MEG和EEG研究中,常常不知道信号到底来自于哪个脑区。而PET成像技术的时间分辨率一般是几分钟,略差于BOLD fMRI,而空间分辨率是厘米级的,略优于EEG和MEG。在fMRI技术中,ALS fMRI(arterial spin labeling fMRI,动脉自旋标记fMRI)在时间稳定性方面非常好,即它可以比较间隔时间长达几天或十几天的两种激活状态。
MERIT DEM a high accuracy global DEM at 3 arc second resolution (~90 m at the equator) produced by eliminating major error components from existing DEMs (NASA SRTM3 DEM, JAXA AW3D DEM, Viewfinder Panoramas DEM). MERIT DEM separates absolute bias, stripe noise, speckle noise and tree height bias using multiple satellite datasets and filtering techniques. After the error removal, land areas mapped with 2 m or better vertical accuracy were increased from 39% to 58%. Significant improvements were found in flat regions where height errors larger than topography variability, and landscapes such as river networks and hill-valley structures became clearly represented.
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Raw对象主要用来存储连续型数据,核心数据为n_channels和times,也包含Info对象。
使用背景方法可以绘制用户数据到地图。这些方法对于绘制 borders,lands等是非常有用的。下面我们就来介绍一下这些内容。
之前小编已经分享过很多空间转录组的分析工具(都可以在空间组专辑里找到哟)。为了方便大家查找,小编将空间转录组常用的去卷积工具和聚类工具做了汇总! 去卷积工具合辑 空间分辨转录组学实验分析的关键步骤之一是确定细胞类型。细胞类型去卷积,是用于估计混合物(数据点)中每种细胞类型的比例以及每个细胞的基因表达水平(在同一数据点内)的算法。 SPOTlight 📷 SPOTlight能够将空间转录组与scRNA-seq数据集成,从而推断复杂组织中细胞类型和状态的位置。其基于一个种子的非负矩阵因子分解回归(Seede
请注意,本文编写于 1197 天前,最后修改于 74 天前,其中某些信息可能已经过时。
Author: bakari Date: 2011.11.23 很久之前自己写的一个NS2 的例子,(一个有线和无线相结合的例子,对于初学很有帮助)欢迎交流! # Define options set val(chan) Channel/WirelessChannel ;# 物理信道类型 set val(prop) Propagation/TwoRayGround ;# 设定无限传输模型 set val(netif) Phy/WirelessPhy ;# 网络接口类型 set val(mac) Mac/8
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