Heard Island: baseline vegetation data for monitoring longterm change.

The production of a detailed vegetation dataset which can act as a sound baseline for detection of change has been a longterm process and has now been completed. There are seven 'child' metadata records, (a) to (g), under the 'parent DIF' (Heard Island: baseline vegetation data for monitoring longterm change, HI_VEG_OVERALL) as follows:(a) Vegetation mapping from orthophotos (HI_VEG_ORTHO_VEGMAP).(b) Vegetation mapping from non-rectified aerial photographs and satellite imagery with accompanying data (HI_VEG_NON_ORTHO_VEGMAP).(c) Orthophotos used for vegetation mapping (HI_VEG_ORTHOPHOTOS_VEGMAP).(d) 35mm photos (oblique aerial and terrestrial) used for vegetation mapping (HI_VEG_PHOTOS_VEGMAP).(e) 35mm photos (terrestrial) from fixed photo-points, 1986-2000 (HI_VEG_PHOTOPOINTS_1).(f) 35mm photos (terrestrial) from fixed photo-points, 2003-2004 (HI_VEG_PHOTOPOINTS_2).(g) Vegetation 'signature points' with accompanying 35mm terrestrial photos (HI_VEG_VEGSIGNATURES).Metadata records (a) to (d) describe the data directly associated with the vegetation mapping project. Records (e) and (f) describe two time-series of photo-monitoring images from a set of fixed photo-points. Record (g) describes a set of 'vegetation signature points' for use in remote sensing analysis. The metadata record 'Heard Island: Terrestrial Biology: Documenting vegetation change on Heard Island' (ASAC_1181) is also relevant to this vegetation dataset.Data collection and analysis have utilised the Australian Antarctic Data Centre's Digital Elevation Model (DEM) of Heard Island and field data from several intensive field seasons (1986-87, 1987-88, 2000-01, 2003-04). Field data collection initially involved mapping of vegetation communities on non-rectified aerial photos and overlays and setting up an extensive series of fixed photo-points for future change detection. Since 2000, fieldwork has also included collection of ground control for orthorectification of aerial photography and satellite imagery (ASAC_1181).The vegetation communities for the majority of the island have been re-mapped on 1986 and 1980 orthophotos and orthophoto mosaics, and screen-digitised using ArcGIS software. The remaining five small vegetated areas of the north coast have not yet been mapped on orthophotos. They have been provisionally mapped using non-rectified airphotos and satellite images, using the same GIS software. Currently the data, and the images, have been included as a separate metadata record as they are not yet geo-referenced.A brief description of the data covered by each 'child' metadata record is as follows:(a) Vegetation mapping from orthophotos (HI_VEG_ORTHO_VEGMAP).i) A shapefile of vegetation polygons covering 13 community types, for most of the island. Vegetation was mapped on orthophotos and orthophoto mosaics (see c) below). The area covered extends from Gilchrist Beach (northeast) to Spit Bay (east) to Long Beach (south), Cape Arkona to Gazert (west) to Laurens Peninsula (northwest) to Atlas Cove area (north). The remaining sections of the north coast are covered in (b) below.ii) A shapefile of polygons indicating reliability of the data.iii) A pdf report detailing the methods used during vegetation mapping and other information.(b) Vegetation mapping from non-rectified aerial photographs and satellite imagery with accompanying data (HI_VEG_NON_ORTHO_VEGMAP).i) The two non-rectified airphotos and three satellite images used for mapping the five areas not covered by HI_VEG_ORTHO_VEGMAP. These areas are Azorella Peninsula, Pageos Moraine/Kildalkey Head, Hoseason Beach, Saddle Point and Cape Bidlingmaier (see AADC).ii) Four shapefiles for each of the five areas, covering vegetation, reliability, aerial photo and satellite image coverage, and 35mm photo locations.iii) A total of 64 x 35mm scanned photos showing general landscape and vegetation of the five areas.(c) Orthophotos used for vegetation mapping (HI_VEG_ORTHOPHOTOS_VEGMAP).i) A shapefile of polygons indicating which orthophotos and orthophoto mosaics were used for the mapping of each area.ii) The orthophotos and orthophoto mosaics used for mapping (see AADC).(d) 35mm photos (oblique aerial and terrestrial) used for vegetation mapping (HI_VEG_PHOTOS_VEGMAP).i) A shapefile showing the approximate locations of the 581 x 35mm photos used as a &ground-check& resource during mapping.ii) A total of 581 x 35mm scanned photos, taken from helicopters, on the ground, and from ships offshore, showing general landscape and vegetation of all areas mapped from orthophotos. These images (along with those in metadata record (b)) are useful for gaining an overall familiarisation of Heard Island coastal terrain and vegetation.(e) 35mm photos (terrestrial) from fixed photo-points, 1986-2000 (HI_VEG_PHOTOPOINTS_1).i) Two shapefiles of 35mm photo locations (differential and hand-held GPS) of the majority of the 35mm fixed photo-point photos which are located in the eastern half of the island (none from the northern part of the island are included).ii) A total of 334 x 35mm scanned terrestrial photos of landscapes and vegetation taken all around the island between 1986 and 2000 (fixed photo-point photos). For use as baseline data for long-term photo-monitoring of vegetation and landscape change. Permission for use needed from researcher.iii) A word document with metadata for the images.iv) An excel spreadsheet with additional information on the images.(f) 35mm photos (terrestrial) from fixed photo-points, 2003-2004 (HI_VEG_PHOTOPOINTS_2).i) Two shapefiles of 35mm photo locations (differential and hand-held GPS) of the majority of the 35mm fixed photo-point photos which are located in the eastern half of the island (none from the northern part of the island are included). As for (e) above. These represent the fixed photopoint photos taken in 2003-2004.ii) Seven folders containing 1633 x 35mm scanned photos of landscapes and vegetation taken in the eastern half of the island in 2003-2004. The majority are re-takes of the fixed photo-point images in metadata record (e), expanded from single images into panoramas. Others represent new photo-points to fill gaps in coverage. For use as baseline data for long-term photo-monitoring of vegetation and landscape change. Permission for use needed from researcher.iii) A word document with metadata for the images.(g) Vegetation 'signature points' with accompanying 35mm terrestrial photos (HI_VEG_VEGSIGNATURES).i) A shapefile of 35mm photo locations of the terrestrial 'vegetation signature' photos.ii) A total of 34 x 35mm scanned photos showing 'vegetation signatures' for elected vegetation communities, for use in remote sensing analysis.iii) A word document with metadata for the images.

一套可作为变化检测可靠基准的精细植被数据集，其构建历经长期筹备，现已正式完成。本父级元数据条目（DIF）"Heard Island: baseline vegetation data for monitoring longterm change, HI_VEG_OVERALL"下共包含7条子元数据记录（a至g），具体如下：
(a) 基于正射影像（orthophoto）的植被制图（HI_VEG_ORTHO_VEGMAP）。
(b) 基于未校正航空摄影照片及配套卫星影像的植被制图（HI_VEG_NON_ORTHO_VEGMAP）。
(c) 植被制图所用正射影像（HI_VEG_ORTHOPHOTOS_VEGMAP）。
(d) 植被制图所用35mm摄影照片（倾斜航空及地面拍摄，HI_VEG_PHOTOS_VEGMAP）。
(e) 1986-2000年固定摄影点位的地面35mm摄影照片（HI_VEG_PHOTOPOINTS_1）。
(f) 2003-2004年固定摄影点位的地面35mm摄影照片（HI_VEG_PHOTOPOINTS_2）。
(g) 配套35mm地面摄影照片的植被特征点（HI_VEG_VEGSIGNATURES）。

子元数据记录(a)至(d)描述了直接关联植被制图项目的各类数据；记录(e)与(f)描述了来自一组固定摄影点位的两期摄影监测影像时序数据；记录(g)则描述了一组用于遥感分析的植被特征点。另有元数据条目《赫德岛：陆地生物学：记录赫德岛的植被变化》（ASAC_1181）与本植被数据集相关。

本数据集的数据采集与分析工作，依托澳大利亚南极数据中心（Australian Antarctic Data Centre, AADC）的赫德岛数字高程模型（Digital Elevation Model, DEM），以及多轮密集野外调查（1986-87、1987-88、2000-01、2003-04）获取的野外数据。初期野外数据采集工作包括：在未校正航空摄影照片及叠加图上绘制植被群落分布图，并布设大量固定摄影点位以用于后续变化检测。2000年以来，野外工作还新增了航空摄影与卫星影像正射校正所需的地面控制点采集工作（ASAC_1181）。

本岛多数区域的植被群落已基于1986年与1980年的正射影像及正射影像镶嵌图完成重新制图，并通过ArcGIS软件完成屏幕数字化。北海岸剩余的5处小型植被覆盖区域尚未通过正射影像完成制图，目前已采用相同GIS软件，基于未校正航空照片与卫星影像进行了暂定性制图。目前，该区域的数据与影像尚未完成地理配准，已作为独立元数据条目单独收录。

各条子元数据记录所涵盖的数据简要说明如下：
(a) 基于正射影像的植被制图（HI_VEG_ORTHO_VEGMAP）。
i) 覆盖全岛多数区域的植被多边形形状文件（shapefile），包含13种植被群落类型。植被制图基于正射影像及正射影像镶嵌图（详见下文c项），制图覆盖范围从吉尔克里斯特海滩（东北部）至斯皮特湾（东部）、朗海滩（南部），从阿科纳角至加泽特（西部）、劳伦斯半岛（西北部）至阿特拉斯湾区域（北部）。北海岸剩余区域的制图内容详见下文b项。
ii) 标注数据可靠性的多边形形状文件。
iii) 一份详细阐述植被制图方法及其他相关信息的PDF报告。

(b) 基于未校正航空摄影照片及配套卫星影像的植被制图（HI_VEG_NON_ORTHO_VEGMAP）。
i) 用于绘制HI_VEG_ORTHO_VEGMAP未覆盖的5处区域的2张未校正航空照片与3张卫星影像，这5处区域分别为阿佐雷拉半岛、帕乔斯冰碛/基尔达尔基角、霍西森海滩、萨德尔角及比德林迈尔角（详见AADC）。
ii) 针对5处区域分别制作的4个形状文件，涵盖植被分布、数据可靠性、航空照片与卫星影像覆盖范围，以及35mm摄影照片点位信息。
iii) 共计64张35mm扫描照片，展示了上述5处区域的整体景观与植被状况。

(c) 植被制图所用正射影像（HI_VEG_ORTHOPHOTOS_VEGMAP）。
i) 标注各区域制图所用正射影像及正射影像镶嵌图的多边形形状文件。
ii) 制图所用正射影像及正射影像镶嵌图（详见AADC）。

(d) 植被制图所用35mm摄影照片（倾斜航空及地面拍摄，HI_VEG_PHOTOS_VEGMAP）。
i) 标注581张35mm摄影照片大致点位的形状文件，这些照片作为制图过程中的地面核查资源。
ii) 共计581张35mm扫描照片，拍摄场景涵盖直升机、地面及近海船只，展示了所有基于正射影像完成制图区域的整体景观与植被状况。这些影像（连同元数据记录b中的影像）可用于全面熟悉赫德岛海岸地形与植被状况。

(e) 1986-2000年固定摄影点位的地面35mm摄影照片（HI_VEG_PHOTOPOINTS_1）。
i) 2个形状文件，标注了本岛东部多数固定摄影点位的35mm照片位置（采用差分GPS与手持GPS采集），未包含本岛北部区域的点位数据。
ii) 共计334张35mm扫描地面照片，拍摄于1986-2000年间，覆盖全岛各地的景观与植被，均为固定摄影点位拍摄的照片，可作为植被与景观长期变化摄影监测的基准数据，使用需经研究人员许可。
iii) 一份包含照片元数据的Word文档。
iv) 一份包含照片补充信息的Excel电子表格。

(f) 2003-2004年固定摄影点位的地面35mm摄影照片（HI_VEG_PHOTOPOINTS_2）。
i) 2个形状文件，标注了本岛东部多数固定摄影点位的35mm照片位置（采用差分GPS与手持GPS采集），未包含本岛北部区域的点位数据，与e项一致，为2003-2004年拍摄的固定摄影点位照片。
ii) 7个文件夹，包含1633张35mm扫描照片，拍摄于2003-2004年间的本岛东部区域，多数为元数据记录e中固定摄影点位照片的重拍影像，已从单张照片扩展为全景图；其余照片为新增摄影点位，用于填补覆盖空白。该数据集可作为植被与景观长期变化摄影监测的基准数据，使用需经研究人员许可。
iii) 一份包含照片元数据的Word文档。

(g) 配套35mm地面摄影照片的植被特征点（HI_VEG_VEGSIGNATURES）。
i) 标注地面植被特征照片点位的形状文件。
ii) 共计34张35mm扫描照片，展示了选定植被群落的特征样例，用于遥感分析。
iii) 一份包含照片元数据的Word文档。