Impact craters (>500 m) in Oxia Planum classified by there degradation state.

This data set contains impact crater rims digitized as
vector polygons in ESRI ArcMap 10.1 Geographic Information System Software to
the CTX mosaic data and categorised based on 4 aspects of their morphology: the rim, ejecta, cross-sectional
shape and stratigraphic relationship and assess their relative degradation
state to what would be expected for a fresh impact crater in Oxia Planum.

Impact crater rims were drawn with vertex spacing of 25 m
at a scale of 1:15,000. In cases where the crater rim was removed, or artefacts
in the CTX mosaic obscured the rim, a best estimate was made based on a
circular perimeter. As this
is qualitative analysis, consequently there may be random errors associated
with the digitization. In particular, craters which are embedded or overlying with
surficial deposits can be quite similar (e.g.; Table 1, rows 2 and 3).
Identification and digitization errors can occur from the CTX image mosaics.
Errors arise from inconsistent georeferencing and colour balance compared with the
original CTX images. In particular, when an impact crater was positioned on an
image seam, parts of or the entire crater could be lost due to stitching. To
mitigate against this we used the original mosaiced CTX images for
classification and THEMIS to correct for errors in position. In addition, as
only visual identification was used to identify ghost craters

本数据集包含对撞击坑边缘进行数字化处理的矢量多边形，该处理在 ESRI ArcMap 10.1 地理信息系统软件中进行，与 CTX 环绕图像进行融合，并根据其形态的四个方面进行分类：坑缘、喷出物、横截面形状及地层关系，评估其相对退化状态，以与奥克西亚平原上新鲜撞击坑的预期状态进行对比。撞击坑边缘以 25 米的顶点间距绘制，比例为 1:15,000。在坑缘被移除或 CTX 环绕图像中的 artifacts 造成的干扰导致边缘无法辨认的情况下，基于圆形周长进行了最佳估计。鉴于这是一项定性分析，因此数字化过程中可能存在随机误差。特别是，嵌入或覆盖地表沉积物的撞击坑可能非常相似（例如，见表 1，第 2 行和第 3 行）。从 CTX 图像镶嵌中可能会发生识别和数字化错误。误差源于与原始 CTX 图像相比，地理参照和色彩平衡的不一致。特别是，当撞击坑位于图像接缝上时，撞击坑的部分或全部可能会因拼接而丢失。为了减轻这一问题，我们在分类过程中使用了原始镶嵌的 CTX 图像，并使用 THEMIS 对位置误差进行校正。此外，由于仅使用了视觉识别来识别幽灵撞击坑，