{"schema":1,"pack_id":"canyon-transects","profiles":[{"id":"ct-sunset","collection":"central","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-collection/sunset-point/profiles.json.gz","packet_sha256":"67045cea0785a841d504cc32f23e34cda07c653b4ad513ac7451049d03767df7","model":"assets/landmark-collection/sunset-point/model.json","model_sha256":"1611a075d005845bbe150214b0b25add9b0debde730067df013d06500f9fcbbf","support_mesh":"assets/landmark-collection/sunset-point/small.glb.gz","support_mesh_sha256":"5add8c793e6b6616228cf51c9c73e0b80534db2b5514408eb83442dee0e6ccb4","grid_interval_m":4,"source_surface_cell_m":1,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Row edges from conservative accepted small-mesh topology; may omit extra edges near fine-grid gaps.","upstream_source_ids":["nps-sunset"],"upstream_source_ledger":"assets/landmark-collection/sources.json"},"row":64,"title":"Sunset Point","subtitle":"From rim to fins","question":"Where does the broad rim give way to a more irregular surface?","reading":"Follow the west-to-east line from the higher plateau toward the broken relief below. Each rise is a change in the retained upper surface; it does not identify an individual hoodoo or a rock layer.","surface":"surfaces/ct-sunset.json","profile":"profiles/ct-sunset.json","svg":"profiles/ct-sunset.svg","surface_method":"upper-envelope","width_m":512,"grid_interval_m":4,"statistics":{"min_m":2293.37,"max_m":2447.03,"relief_m":153.6600000000003,"retained_length_m":512,"retained_fraction":1,"gap_intervals":0}},{"id":"ct-wall-street","collection":"central","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-collection/wall-street/profiles.json.gz","packet_sha256":"84eb2481895cc9802647e362f5f2255433ecb20f31b8d6de567d92880a8b765d","model":"assets/landmark-collection/wall-street/model.json","model_sha256":"71c9562aab60bf8d7e8ac4ec69af84b4d8af24b74818112b821049563e9c004b","support_mesh":"assets/landmark-collection/wall-street/small.glb.gz","support_mesh_sha256":"fe24bf65fc072910404c16afc4a0130f1cc0a2b1833624d9a03e1f88fa0c6026","grid_interval_m":2.5,"source_surface_cell_m":0.625,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Row edges from conservative accepted small-mesh topology; may omit extra edges near fine-grid gaps.","upstream_source_ids":["nps-navajo","nps-sunset"],"upstream_source_ledger":"assets/landmark-collection/sources.json"},"row":64,"title":"Wall Street","subtitle":"A narrow crop, a steep story","question":"How much of this short section is taken up by a steep change in height?","reading":"Compare its 320 m width with the broader northern studies at a shared scale. Airborne upper-envelope data can connect returns across steep faces, but cannot describe the hidden walls of the passage.","surface":"surfaces/ct-wall-street.json","profile":"profiles/ct-wall-street.json","svg":"profiles/ct-wall-street.svg","surface_method":"upper-envelope","width_m":320,"grid_interval_m":2.5,"statistics":{"min_m":2343.02,"max_m":2415.43,"relief_m":72.40999999999985,"retained_length_m":320,"retained_fraction":1,"gap_intervals":0}},{"id":"ct-inspiration","collection":"central","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-collection/inspiration-point/profiles.json.gz","packet_sha256":"92bf164373075f316ef7ea48ce08d47549455fdf78453dc4b8df60c159595174","model":"assets/landmark-collection/inspiration-point/model.json","model_sha256":"5f67b9a9ed17626237a114ba84e40a5d6e40166fa49e0e4ae451f017b82a2056","support_mesh":"assets/landmark-collection/inspiration-point/small.glb.gz","support_mesh_sha256":"996ebcc5bc911b463dfa62e0d5c74c98e2f94620603766b5777764289c298e72","grid_interval_m":5,"source_surface_cell_m":1.25,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Row edges from conservative accepted small-mesh topology; may omit extra edges near fine-grid gaps.","upstream_source_ids":["nps-inspiration"],"upstream_source_ledger":"assets/landmark-collection/sources.json"},"row":64,"title":"Inspiration Point","subtitle":"The edge in section","question":"Does the descent happen in one step or through several changes in slope?","reading":"Trace the retained surface without assuming every small peak is a distinct rock feature. Moving the slice north or south changes the terrain it intersects; these are parallel sections, not a trail.","surface":"surfaces/ct-inspiration.json","profile":"profiles/ct-inspiration.json","svg":"profiles/ct-inspiration.svg","surface_method":"upper-envelope","width_m":640,"grid_interval_m":5,"statistics":{"min_m":2307.88,"max_m":2521.97,"relief_m":214.0899999999997,"retained_length_m":640,"retained_fraction":1,"gap_intervals":0}},{"id":"ct-rainbow","collection":"central","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-collection/rainbow-point/profiles.json.gz","packet_sha256":"dafb41106721a425bc7d4122cd0738288666eb76e4066b108f720ebdf74f6c13","model":"assets/landmark-collection/rainbow-point/model.json","model_sha256":"8e3f2621a6c77bceb6af1c52319749cd98b9ef4b8cbdf82ce1c3729d73fe4d14","support_mesh":"assets/landmark-collection/rainbow-point/small.glb.gz","support_mesh_sha256":"6f8e522e48de647d0cd43c2cbf8526a6ac704897fcfaad84e411557ae0569830","grid_interval_m":6,"source_surface_cell_m":1.5,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Row edges from conservative accepted small-mesh topology; may omit extra edges near fine-grid gaps.","upstream_source_ids":["nps-rainbow","nps-yovimpa"],"upstream_source_ledger":"assets/landmark-collection/sources.json"},"row":48,"title":"Rainbow Point","subtitle":"A ground-only view","question":"How different is the shape when the source selects ground returns?","reading":"This packet uses classified ground. Trees and standing rock can be omitted by classification. Its original profile note says upper envelope, but the model metadata and source pipeline identify classified ground; this section uses that documented method.","surface":"surfaces/ct-rainbow.json","profile":"profiles/ct-rainbow.json","svg":"profiles/ct-rainbow.svg","surface_method":"classified-ground","width_m":768,"grid_interval_m":6,"statistics":{"min_m":2707.77,"max_m":2779.68,"relief_m":71.90999999999985,"retained_length_m":768,"retained_fraction":1,"gap_intervals":0}},{"id":"ct-boat-mesa","collection":"north","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/north/boat-mesa/profiles.json.gz","packet_sha256":"8cd1067049f2bd0e9ebf1b8f8196e6179ac98f0206e8f475a43d114da65094e9","model":"assets/landmark-extensions/north/boat-mesa/model.json","model_sha256":"2ad50bd390579a407ebad4f5cc4e5a54b38b00aea725f2f7febaabe7fe538146","support_mesh":"assets/landmark-extensions/north/boat-mesa/small.glb.gz","support_mesh_sha256":"c3aa19a10a8bf7bde6c179d4db5b54396b12465b7f3ce2b2acfa5769c619c674","grid_interval_m":8,"source_surface_cell_m":2,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["gnis-north","nps-fairyland"],"upstream_source_ledger":"assets/landmark-extensions/north/sources.json"},"row":48,"title":"Boat Mesa","subtitle":"A wider piece of the plateau","question":"What changes when a 1,024 m section shares a scale with a 320 m section?","reading":"The larger crop gives context to the relief. Compare it with Wall Street in relative-height mode to see both horizontal extent and relief without stretching either section to fit. No geologic contact is inferred from the line.","surface":"surfaces/ct-boat-mesa.json","profile":"profiles/ct-boat-mesa.json","svg":"profiles/ct-boat-mesa.svg","surface_method":"classified-ground","width_m":1024,"grid_interval_m":8,"statistics":{"min_m":2236.52,"max_m":2458.97,"relief_m":222.44999999999982,"retained_length_m":960,"retained_fraction":0.9375,"gap_intervals":4}},{"id":"ct-sinking-ship","collection":"north","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/north/sinking-ship/profiles.json.gz","packet_sha256":"df72f2f3218609c79597fd0839f1180490afb6e28d61db34389c704b60f0d911","model":"assets/landmark-extensions/north/sinking-ship/model.json","model_sha256":"7509c280c8737f81fd231c62b6d1e6a7be284b06a80de3cfd53b6ba36fa5ca56","support_mesh":"assets/landmark-extensions/north/sinking-ship/small.glb.gz","support_mesh_sha256":"3bab0410be4597c60fa7f1d487d823dd1ebe2dcd6e43701b058c967b8d6ebf0f","grid_interval_m":6,"source_surface_cell_m":1.5,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["gnis-north","nps-fairyland"],"upstream_source_ledger":"assets/landmark-extensions/north/sources.json"},"row":64,"title":"Sinking Ship","subtitle":"The shape above ground","question":"Can a topographic line alone tell you the tilt of buried beds?","reading":"The ground-class section records surface shape. It does not measure bed orientation, locate a fault or extend rock layers below the surface. Compare adjacent slices to see how much the visible shape depends on the cut.","surface":"surfaces/ct-sinking-ship.json","profile":"profiles/ct-sinking-ship.json","svg":"profiles/ct-sinking-ship.svg","surface_method":"classified-ground","width_m":768,"grid_interval_m":6,"statistics":{"min_m":2166.88,"max_m":2334.65,"relief_m":167.76999999999998,"retained_length_m":678,"retained_fraction":0.8828125,"gap_intervals":6}},{"id":"ct-china-wall","collection":"north","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/north/china-wall/profiles.json.gz","packet_sha256":"113144a887293a1601ebb727d765c61693e7329b7a59140e28e4b68df41e0ae3","model":"assets/landmark-extensions/north/china-wall/model.json","model_sha256":"85e8c9e5af7ccecd92bc13d82a48ed2ffaf72eaa18cffd93152f35a61ed8197e","support_mesh":"assets/landmark-extensions/north/china-wall/small.glb.gz","support_mesh_sha256":"0bd6ff16b006cd63fb8ceaab961c567e59442403304a26533d9b1268a0910955","grid_interval_m":4,"source_surface_cell_m":1,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["gnis-north","nps-china-archive","usgs-geology"],"upstream_source_ledger":"assets/landmark-extensions/north/sources.json"},"row":64,"title":"China Wall","subtitle":"A ridge at landscape scale","question":"Which small rises survive when the whole ridge is drawn at true scale?","reading":"The packet names this China Wall; its GNIS name record is Chinese Wall. The section samples a filtered upper envelope across the surrounding crop, not a surveyed wall face or the hidden spaces between pillars.","surface":"surfaces/ct-china-wall.json","profile":"profiles/ct-china-wall.json","svg":"profiles/ct-china-wall.svg","surface_method":"upper-envelope","width_m":512,"grid_interval_m":4,"statistics":{"min_m":2272.1,"max_m":2325.93,"relief_m":53.82999999999993,"retained_length_m":512,"retained_fraction":1,"gap_intervals":0}},{"id":"ct-tower-bridge","collection":"north","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/north/tower-bridge/profiles.json.gz","packet_sha256":"1798241e28462e30ab245072b1fc26ce2f99b7f7c752d7399bf921cce2c63a38","model":"assets/landmark-extensions/north/tower-bridge/model.json","model_sha256":"397fc6ebef3fa71b447d80c4c38bbb1bc3897c7623b3756522590f8a51a9ae1d","support_mesh":"assets/landmark-extensions/north/tower-bridge/small.glb.gz","support_mesh_sha256":"14acde8c605136dab9117a27cc806bf1ab67a3f6fce5e6cee8963bb3abba646d","grid_interval_m":4,"source_surface_cell_m":1,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["nps-tower","nps-pois","osm-locators"],"upstream_source_ledger":"assets/landmark-extensions/north/sources.json"},"row":72,"title":"Tower Bridge context","subtitle":"An honest break in the line","question":"What can a blank interval tell you about the limits of a model?","reading":"The source deliberately omits a footprint around unresolved arch, pillar and underside geometry. The hatched interval is withheld data, not a measured opening. Neither the plan nor the section fills this gap.","surface":"surfaces/ct-tower-bridge.json","profile":"profiles/ct-tower-bridge.json","svg":"profiles/ct-tower-bridge.svg","surface_method":"upper-envelope","width_m":512,"grid_interval_m":4,"statistics":{"min_m":2189.72,"max_m":2268.39,"relief_m":78.67000000000007,"retained_length_m":368,"retained_fraction":0.71875,"gap_intervals":1}},{"id":"ct-hat-shop","collection":"south","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/south/hat-shop/profiles.json.gz","packet_sha256":"303a5ccef1b1212ba8427e454255ec81cd237509e32fed1781d24b08c54ff8c4","model":"assets/landmark-extensions/south/hat-shop/model.json","model_sha256":"edcdfc1dbba0e1b1a82ef4d3ca1595905387dffc63abc00260036fd76cf726cd","support_mesh":"assets/landmark-extensions/south/hat-shop/small.glb.gz","support_mesh_sha256":"83684412713f9e24c00b54cd90cc0c842d8ac88b647e14cbf7932145a807807b","grid_interval_m":3.75,"source_surface_cell_m":0.9375,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["nps-hat-shop","nps-pois","gnis"],"upstream_source_ledger":"assets/landmark-extensions/south/sources.json"},"row":64,"title":"Hat Shop slopes","subtitle":"The slope beneath the forms","question":"Which parts of a landform might disappear in a classified-ground surface?","reading":"The ground-class packet describes the surrounding slope. It cannot represent both a cap and its narrower column at the same horizontal position. Ground classification may omit the standing formations themselves.","surface":"surfaces/ct-hat-shop.json","profile":"profiles/ct-hat-shop.json","svg":"profiles/ct-hat-shop.svg","surface_method":"classified-ground","width_m":480,"grid_interval_m":3.75,"statistics":{"min_m":2170.32,"max_m":2262.35,"relief_m":92.02999999999975,"retained_length_m":476.25,"retained_fraction":0.9921875,"gap_intervals":1}},{"id":"ct-swamp","collection":"south","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/south/swamp-canyon/profiles.json.gz","packet_sha256":"9ed0b3930ff3d36d75e3e9610513f810ec4c80882ebac1c5e6c148d1c6785694","model":"assets/landmark-extensions/south/swamp-canyon/model.json","model_sha256":"894c1017a3a0a51370e0b7076a15564cdcd00041e4f44f19f745be1c76dab54b","support_mesh":"assets/landmark-extensions/south/swamp-canyon/small.glb.gz","support_mesh_sha256":"34ef3d51b5304c72eaa490dd0396baaa3c3ce42773227ebc0bb19a4601bd61a5","grid_interval_m":6,"source_surface_cell_m":1.5,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["nps-swamp","nps-pois","gnis"],"upstream_source_ledger":"assets/landmark-extensions/south/sources.json"},"row":80,"title":"Swamp Canyon","subtitle":"The interruptions matter","question":"Would connecting the gaps make this section look more certain than it is?","reading":"Leave the omitted intervals open. The southern packets omit unsupported nodes and some abrupt interpolated cliff or isolated-patch geometry. Nearby valid endpoints alone are not permission to connect a segment.","surface":"surfaces/ct-swamp.json","profile":"profiles/ct-swamp.json","svg":"profiles/ct-swamp.svg","surface_method":"classified-ground","width_m":768,"grid_interval_m":6,"statistics":{"min_m":2365.09,"max_m":2507.88,"relief_m":142.78999999999996,"retained_length_m":720,"retained_fraction":0.9375,"gap_intervals":3}},{"id":"ct-ponderosa","collection":"south","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/south/ponderosa-canyon/profiles.json.gz","packet_sha256":"e27e91e27ba4fda9baa9c03db1f5815d6d7dbf28ff0622e3bd98e54eb7ee9789","model":"assets/landmark-extensions/south/ponderosa-canyon/model.json","model_sha256":"4cde91f9ae0ac2ac24aca1afee2c40c3f7b398c1e9e529002a16e85873ccec7d","support_mesh":"assets/landmark-extensions/south/ponderosa-canyon/small.glb.gz","support_mesh_sha256":"36bfac996fc23d44444ef5031846b0fdb5f2aa20f6962c63660714372b7ca51d","grid_interval_m":6,"source_surface_cell_m":1.5,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["nps-ponderosa","nps-pois","gnis"],"upstream_source_ledger":"assets/landmark-extensions/south/sources.json"},"row":48,"title":"Ponderosa Canyon","subtitle":"Relief without exaggeration","question":"How does the apparent steepness change at 1×, 2× and 4× vertical scale?","reading":"Start at equal horizontal and vertical scale. Exaggeration can reveal small height differences, but changes the apparent slope. The exported section records the display scale separately from the unchanged elevation values.","surface":"surfaces/ct-ponderosa.json","profile":"profiles/ct-ponderosa.json","svg":"profiles/ct-ponderosa.svg","surface_method":"classified-ground","width_m":768,"grid_interval_m":6,"statistics":{"min_m":2439.71,"max_m":2717.6,"relief_m":277.8899999999999,"retained_length_m":690,"retained_fraction":0.8984375,"gap_intervals":5}},{"id":"ct-black-birch","collection":"south","source":{"dataset_id":"USGS_LPC_UT_Southern_QL1_2018_LAS_2019","acquired":"2018-04-27 / 2018-07-29 project interval","published":"2019-06-03","credit":"Map services and data available from U.S. Geological Survey, National Geospatial Program.","rights":"US Government Public Domain","packet":"assets/landmark-extensions/south/black-birch-canyon/profiles.json.gz","packet_sha256":"f6208e1836b55dc700193ae936e6212cd5e800660b5fd0f1a747b78f17895a33","model":"assets/landmark-extensions/south/black-birch-canyon/model.json","model_sha256":"87ce9c0a588358854f958f98a450f93d0c71471ea5caf6251b8cfbf43dbc18bf","support_mesh":"assets/landmark-extensions/south/black-birch-canyon/small.glb.gz","support_mesh_sha256":"536c55890162ac23382426cac857172301187db4854e145072a56e63523a4636","grid_interval_m":6,"source_surface_cell_m":1.5,"height_encoding":"centimetres above base_m; encoding precision is not measurement accuracy","gap_policy":"Original row-segment mask; plan cells from conservative accepted small-mesh topology.","upstream_source_ids":["nps-black-birch","nps-pois","gnis"],"upstream_source_ledger":"assets/landmark-extensions/south/sources.json"},"row":64,"title":"Black Birch Canyon","subtitle":"Another window on the rim","question":"How much does moving a parallel slice change the sequence of rises and falls?","reading":"Move the section through the packet and watch the same line update in plan, oblique and profile views. The crop is an editorial window, and its edges are not natural landscape boundaries.","surface":"surfaces/ct-black-birch.json","profile":"profiles/ct-black-birch.json","svg":"profiles/ct-black-birch.svg","surface_method":"classified-ground","width_m":768,"grid_interval_m":6,"statistics":{"min_m":2503.31,"max_m":2720.02,"relief_m":216.71000000000004,"retained_length_m":684,"retained_fraction":0.890625,"gap_intervals":4}}],"scenes":[{"id":"rim","number":"01","title":"Rim to floor","profile":"ct-sunset","compare":"","row":64,"prompt":"Trace a slice from plateau to broken relief. Move it north or south and follow the same line in three views."},{"id":"scale","number":"02","title":"Across scales","profile":"ct-boat-mesa","compare":"ct-wall-street","row":48,"prompt":"A broad mesa and a narrow canyon crop share exactly the same metre scale. The shorter line stays shorter."},{"id":"gaps","number":"03","title":"The missing surface","profile":"ct-tower-bridge","compare":"","row":72,"prompt":"An intentional omission is part of the evidence. Inspect the break without turning it into an invented opening."},{"id":"ground","number":"04","title":"Ground beneath","profile":"ct-ponderosa","compare":"ct-hat-shop","row":48,"prompt":"Read two classified-ground sections at equal scale. Their shapes do not include every standing rock or tree."}]}