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Elevation and slope statistics for the Mars Express HRSC DTM tiles used in Martian glacier work

Dec 1, 2016

In the last post I noted the distribution of glacier-like forms according to elevation relative to Mars datum, and slope, as measured by the Mars Express HRSC DTM data.

One issue is whether the distribution according to elevation is a primary function of elevation, or the fact that the distribution of slope varies according to elevation in the area of study.

The distribution of slope and elevation was considered previously:

What will be needed however is the histogram of slope as a function of elevation. Below is a table of 179 HRSC DTM tiles that contain coverage of Souness objects, detailing mean, minimum and maximum elevation and slope, etc. A more comprehensive statistical assessment would use all HRSC DTM tiles that exist in the latitude range 25° - 70° that Souness studied.

Here are a couple of plots, showing the mean slope as a function of mean elevation, with errorbars, and the area of the plotting symbol proportional to the area of each tile, and a plot showing the proportion of each tile having slope exceeding 5° and 10° respectively.

Table of HRSC tiles

For comparison, the area of the UK is 243600km2. Several individual tiles are larger than this, the largest being h0533. The average area of each tile is 87055km2. Total area, ignoring overlap is 15.6 million km2, and taking account of overlap, it is 13.4 million km2. To find more about an individual tile, click on the link in the first column to the tile's page on Arizona State University's Mars Image Explorer or using HRSCview.
FieldDimensionsDTM ResolutionCentre locationAreaMean elevMin elevMax elevAverage slopePercentage exceeding 10°
h0022_0000(12781, 1173) px100m100.9°E, 29.4°S98445km2314.1-235643995.4°16.9%
h0037_0000(36203, 4729) px50m131.9°W, 29.4°N217870km21762.4-2722212345.5°16.3%
h0248_0000(6562, 1216) px50m102.6°E, 37.2°S18548km2110.1-81633584.1°9.8%
h0266_0000(6715, 1463) px50m94.7°W, 43.3°S18355km23653.4200284273.5°6.0%
h0280_0000(8361, 1039) px75m153.6°E, 39.9°S34376km2754.2-5218422.8°3.8%
h0365_0000(10801, 1685) px75m90.7°E, 45.5°S56958km2-4177.5-5841-4593.3°4.3%
h0368_0000(12191, 1663) px75m118.3°E, 41.9°S67909km2783.8-72828083.1°5.5%
h0376_0000(13048, 2782) px50m29.1°W, 48.7°S46781km2-346.6-339237305.6°17.2%
h0383_0000(1601, 1068) px75m37.9°W, 43.1°S8767km2-1715.5-430510256.4°21.4%
h0394_0000(7360, 1523) px75m52.0°W, 42.4°S42870km2561.4-184737417.9°29.9%
h0397_0000(22832, 2260) px75m13.0°E, 37.1°S146656km21612.3-14329813.7°5.4%
h0416_0000(8537, 1457) px100m55.2°W, 46.6°S73480km2236.5-251336085.9°17.7%
h0424_0000(10549, 2394) px50m121.4°W, 44.3°S45403km22071.658835262.9°3.4%
h0427_0000(8101, 2100) px75m57.1°W, 44.0°S53877km21200.5-123037354.8°12.0%
h0451_0000(6222, 2598) px100m103.2°E, 38.8°S70761km2-87.0-255746924.5°11.3%
h0453_0000(10385, 1838) px75m92.0°W, 41.2°S79320km24257.265089784.0°6.9%
h0466_0000(6081, 1339) px150m69.7°E, 20.8°S145309km2-327.9-446936384.9°10.7%
h0469_0000(7227, 2011) px75m135.0°E, 40.5°S63422km21630.0-58127863.0°5.1%
h0478_0000(18069, 2865) px125m30.2°W, 23.6°S410550km2-1037.0-466121675.6°15.8%
h0479_0000(3458, 1348) px100m128.1°W, 42.7°S40474km22102.051548373.2°5.6%
h0497_0000(10101, 1885) px100m97.0°W, 37.0°S135551km24503.0182873793.4°4.5%
h0506_0000(11762, 1920) px125m98.3°E, 33.1°S221775km2-367.1-317554583.5°8.1%
h0508_0000(12599, 2646) px75m98.8°W, 34.0°S138944km25258.3242991554.1°7.3%
h0528_0000(11402, 2553) px100m93.1°E, 29.6°S208685km2-599.9-523036963.6°6.8%
h0533_0000(13073, 2294) px150m38.2°W, 22.0°S456221km2-409.1-543026405.6°15.0%
h0544_0000(2790, 1207) px150m37.9°W, 40.6°S66060km2-985.3-428822205.3°15.2%
h0550_0000(4445, 1789) px125m92.3°E, 32.5°S111078km2-2117.2-539012213.0°5.8%
h0558_0000(6320, 2251) px125m25.5°E, 32.1°S174245km21948.4-16135622.9°5.5%
h0988_0000(14122, 1433) px75m77.2°E, 22.5°N83411km2-1307.1-352315056.2°18.5%
h1201_0000(5202, 1373) px75m24.6°E, 43.5°N28478km2-3224.1-3909-17324.7°12.1%
h1210_0000(2491, 931) px75m138.1°W, 39.0°N12230km2-1629.8-31681794.9°11.2%
h1232_0000(3912, 1097) px75m140.3°W, 37.4°N17785km2-1977.9-3581-54.6°10.2%
h1241_0000(4672, 1362) px75m54.2°E, 44.6°N24804km2-2578.1-3295-1835.3°13.8%
h1258_0000(5101, 1072) px75m177.6°W, 32.5°N22915km2-3837.0-4161-26103.5°9.3%
h1312_0000(7271, 1337) px75m84.7°W, 35.8°N36762km2926.3-100127004.6°9.7%
h1316_0000(5401, 1233) px100m119.7°W, 31.7°N40045km21893.066328212.1°0.9%
h1317_0000(4001, 886) px100m144.6°E, 31.7°N28788km2-1767.1-468116802.8°3.1%
h1351_0000(8402, 1977) px75m41.0°E, 47.4°N48721km2-2762.2-46599783.8°7.6%
h1391_0000(12890, 1476) px100m68.3°E, 37.3°N120274km2-1699.3-508015734.9°12.9%
h1395_0000(5203, 1512) px100m34.7°E, 43.5°N44511km2-2828.2-4259-6984.4°10.1%
h1412_0000(11403, 1941) px100m165.0°E, 41.4°N113313km2-3078.8-41784874.0°9.3%
h1423_0000(15994, 2143) px75m163.3°E, 39.5°N127585km2-3021.1-40722833.5°6.7%
h1428_0000(13002, 3085) px75m30.3°E, 42.3°N102455km2-2734.8-71531654.7°11.0%
h1429_0000(20803, 3289) px75m67.5°W, 39.2°N171804km2-966.9-376513264.8°11.5%
h1446_0000(11318, 2014) px100m60.8°E, 38.4°N133749km2-1916.4-37977675.7°16.9%
h1450_0000(18203, 4148) px75m27.8°E, 41.8°N163141km2-2807.8-7127-1694.9°11.8%
h1461_0000(16986, 4749) px75m25.4°E, 43.9°N154244km2-2924.2-6588-4923.6°6.3%
h1468_0000(19462, 3367) px75m58.6°E, 47.6°N169273km2-3114.9-5556-383.0°5.7%
h1483_0000(11102, 3084) px100m23.5°E, 42.8°N143811km2-3036.0-4265-6713.5°6.6%
h1498_0000(7603, 2119) px100m11.6°W, 34.3°N110710km2-3640.2-5207-21654.3°8.1%
h1523_0000(10543, 3418) px75m49.8°E, 43.1°N116809km2-1814.8-36369144.3°10.5%
h1526_0000(5503, 2821) px75m115.0°E, 40.1°N63553km2-4952.7-6556-43012.1°1.7%
h1528_0000(16803, 3537) px75m80.5°W, 40.3°N196042km2480.7-296527914.1°7.9%
h1545_0000(9373, 3847) px75m46.5°E, 44.1°N113871km2-2069.4-42126645.1°14.8%
h1550_0000(16403, 3782) px75m83.5°W, 41.0°N208952km2419.0-257332224.1°8.6%
h1578_0000(8602, 3013) px100m43.0°E, 44.1°N160965km2-2107.2-448310323.8°7.9%
h1600_0000(7501, 2721) px125m38.6°E, 39.7°N199966km2-1366.3-39009723.7°6.5%
h1607_0000(5002, 2045) px175m71.4°E, 38.0°N226517km2-2320.6-41328894.3°11.3%
h1628_0000(5002, 3727) px100m165.4°E, 40.9°N138771km2-3025.3-46704553.6°7.5%
h1629_0000(5302, 2471) px150m63.3°E, 38.9°N215818km2-2235.9-4490124.6°12.3%
h1644_0000(1952, 1607) px175m33.7°E, 40.4°N86440km2-1930.3-37625413.7°6.7%
h1887_0000(2502, 1418) px250m108.5°E, 41.6°S171008km2675.1-92044294.4°10.0%
h1932_0000(4227, 1298) px225m6.4°E, 40.5°S206200km21318.3-160727203.1°3.5%
h1937_0000(9003, 1817) px100m125.1°W, 30.9°S125929km22777.4111541732.6°2.8%
h2159_0000(4012, 1367) px75m19.6°E, 45.6°S26129km21506.139430483.3°3.6%
h2181_0000(4804, 1207) px100m17.4°E, 48.3°S43588km21551.670228412.5°2.9%
h2195_0000(3952, 993) px100m82.8°E, 45.1°S31518km2-6126.6-7179-53862.8°2.1%
h2197_0000(2011, 1302) px100m114.0°W, 52.0°S19989km21505.8-35434285.1°11.9%
h2210_0000(1502, 1067) px100m47.2°E, 48.3°S12625km2-2184.6-454210645.7°18.5%
h2220_0000(5682, 2373) px75m144.4°E, 48.1°S34383km21560.7-11532083.7°6.0%
h2224_0000(6432, 1196) px75m112.9°E, 41.3°S27821km2632.7-148437164.5°10.4%
h2247_0000(8833, 2025) px75m12.3°E, 53.5°S58270km21553.7-13527802.9°2.9%
h2279_0000(8393, 1550) px50m108.5°E, 41.5°S24411km2670.6-34443196.0°18.2%
h2287_0000(11802, 3213) px75m41.7°E, 55.2°S77249km2267.2-111320022.1°1.7%
h2312_0000(6001, 1723) px75m106.7°E, 43.4°S27029km2286.2-39923423.6°5.6%
h2345_0000(2401, 1116) px75m104.5°E, 45.1°S11286km2-130.5-125646193.5°6.3%
h2356_0000(2802, 974) px75m103.6°E, 40.5°S13506km2-34.6-168547015.3°16.6%
h2359_0000(2832, 1177) px75m169.2°E, 45.8°S13662km21732.517332114.6°10.9%
h2386_0000(13002, 2303) px75m36.8°E, 50.3°S71588km2564.7-100515302.7°3.5%
h2387_0000(10002, 1899) px75m61.0°W, 48.0°S54648km21497.9-65632444.9°11.6%
h2400_0000(2613, 1613) px50m102.2°E, 40.5°S9657km2-699.9-248140634.1°9.6%
h2403_0000(8652, 1648) px75m167.8°E, 50.0°S50246km22010.549531593.3°4.8%
h2430_0000(6606, 1747) px75m35.6°E, 52.1°S40109km2739.1-73515822.4°2.3%
h2438_0000(10043, 1416) px100m30.2°W, 45.4°S85303km2-494.9-338133585.0°13.2%
h2441_0000(13702, 2759) px75m33.8°E, 50.5°S87345km2890.6-128422104.0°7.3%
h2460_0000(7274, 1464) px100m31.8°W, 47.6°S66541km2-952.4-328524475.5°16.7%
h2466_0000(3562, 1519) px100m98.9°E, 41.5°S35078km2-1243.3-278326174.0°9.4%
h2475_0000(5903, 1822) px75m65.2°W, 46.1°S43430km21863.8-42336723.9°5.8%
h2493_0000(9635, 2247) px75m33.6°W, 49.3°S75915km2-950.4-268261135.9°18.6%
h2494_0000(15301, 2927) px75m131.8°W, 49.7°S121366km22181.430344513.7°5.4%
h2501_0000(3501, 1770) px75m99.7°W, 47.8°S28233km22931.554938783.1°4.5%
h2508_0000(15095, 3569) px100m67.7°W, 54.1°S171382km21469.5-86835453.2°3.0%
h2510_0000(4885, 1230) px125m96.6°E, 40.5°S75220km2-2179.3-543630174.4°9.6%
h2515_0000(16219, 6793) px75m36.8°W, 62.6°S149827km2783.7-271861433.4°7.5%
h2526_0000(6887, 1443) px125m35.4°W, 39.0°S116216km2-717.2-322428885.1°14.0%
h2527_0000(5006, 1956) px75m133.8°W, 43.0°S47661km22001.1-9433773.4°4.6%
h2529_0000(10450, 2096) px100m29.8°E, 48.0°S131221km21640.6-2633633.1°4.9%
h2530_0000(9003, 1937) px125m68.6°W, 33.4°S188667km23159.135659173.9°5.6%
h2538_0000(5029, 1263) px150m134.4°W, 34.7°S113579km21867.03632682.8°3.8%
h2540_0000(4782, 1518) px150m28.9°E, 32.8°S128114km21751.6-6631673.8°6.3%
h2541_0000(13269, 3723) px100m70.0°W, 55.8°S174235km21531.7-56237883.2°4.3%
h2550_0000(5801, 2127) px100m126.0°E, 43.3°S85395km21425.5-61135384.1°7.2%
h2595_0000(7500, 1778) px150m24.5°E, 41.9°S202177km22128.610338012.6°2.8%
h2596_0000(7469, 2162) px125m74.3°W, 34.8°S188443km23766.4183171053.4°4.0%
h2607_0000(9723, 3249) px100m75.3°W, 49.5°S174840km22141.2-9339693.1°2.9%
h2609_0000(4484, 1891) px125m88.5°E, 39.6°S110090km2-4757.3-6323-27383.0°3.8%
h2612_0000(8101, 3567) px100m152.9°E, 50.5°S146882km21264.3-63430763.2°3.6%
h2613_0000(1552, 1243) px200m55.2°E, 32.0°S71030km2-4570.5-75236545.1°10.3%
h2625_0000(2802, 1977) px150m44.2°W, 39.0°S104012km2-396.2-307931605.5°16.5%
h2631_0000(4801, 1724) px175m86.0°E, 36.2°S196628km2-3991.4-644642903.4°6.1%
h2638_0000(5134, 2061) px150m118.0°E, 37.1°S184526km2764.2-79228492.4°3.6%
h2639_0000(5502, 1922) px150m19.9°E, 39.9°S182385km21856.0-34237572.8°3.2%
h2640_0000(7401, 2142) px150m78.2°W, 42.1°S242593km23239.4-114970852.9°3.6%
h2644_0000(3752, 2019) px150m111.4°W, 45.0°S123347km22524.645243603.1°4.3%
h2660_0000(3838, 1899) px175m115.6°E, 38.0°S166908km2746.1-138133262.5°4.0%
h2665_0000(4323, 2316) px125m15.4°W, 42.1°S131624km2946.2-158723303.5°4.9%
h2669_0000(2373, 1508) px200m48.7°W, 38.2°S122633km2758.1-171439465.5°17.5%
h2681_0000(2652, 1704) px175m148.1°W, 44.8°S118773km22258.49645553.0°4.5%
h2689_0000(4201, 2187) px150m145.4°E, 39.2°S173432km21473.9-119931412.7°4.1%
h2694_0000(2861, 1379) px250m13.7°E, 38.8°S199978km21633.5-46430072.5°3.1%
h2864_0000(2206, 1891) px175m58.0°E, 35.2°N92242km2-1283.3-32853464.9°13.4%
h2878_0000(1682, 1190) px250m121.8°E, 37.3°N104112km2-4714.1-6381-39591.4°1.0%
h2908_0000(5594, 2184) px150m53.4°E, 41.4°N214663km2-1762.7-34746313.8°7.8%
h2913_0000(4962, 1513) px175m78.0°W, 35.1°N178236km2675.9-77120783.5°4.5%
h2996_0000(2801, 806) px150m44.9°E, 28.9°N45651km2-996.3-25113153.4°3.5%
h3249_0000(8001, 1690) px75m21.4°E, 44.4°N47924km2-3560.4-5099-12043.4°6.6%
h3253_0000(7142, 1678) px50m9.6°W, 40.5°N24933km2-4278.1-4996-31774.3°10.8%
h3272_0000(1912, 1284) px75m77.5°W, 47.0°N11410km255.9-302818894.1°7.5%
h3283_0000(5353, 1318) px75m78.7°W, 45.3°N29879km2815.1-266026783.4°4.7%
h3289_0000(4141, 1061) px100m51.1°E, 45.9°N31014km2-2653.7-3596-6465.1°12.4%
h3316_0000(2772, 1447) px75m83.0°W, 46.5°N15598km2614.1-110527926.7°19.3%
h4087_0000(10465, 1175) px100m80.2°W, 31.1°S91348km23431.6189354463.1°3.6%
h4180_0000(4501, 971) px100m141.2°E, 38.8°S34336km21633.812332624.0°7.7%
h4234_0000(3601, 1185) px75m125.5°W, 40.2°S17789km22382.7115647444.5°8.5%
h4293_0000(2501, 1002) px75m163.4°W, 43.0°S11825km21362.858734174.8°10.7%
h4330_0000(6901, 1022) px75m160.5°E, 36.9°S30127km21012.0-96923644.2°7.5%
h4365_0000(5002, 1218) px75m39.6°W, 35.4°S23863km2121.8-276518775.0°12.7%
h4376_0000(4453, 1027) px100m40.7°W, 36.0°S29258km297.7-178221125.5°15.7%
h5081_0000(11371, 2145) px75m92.4°W, 36.0°N104607km2777.6-70329961.9°2.8%
h5173_0000(14685, 1201) px75m63.0°E, 27.1°N72584km2-309.5-262822635.6°15.4%
h5195_0000(5743, 1104) px75m22.4°E, 32.3°N30026km2-1848.9-4014-2084.9°9.9%
h5213_0000(9533, 1474) px75m20.6°E, 34.8°N52161km2-2087.6-3904-2044.9°11.1%
h5249_0000(9682, 1367) px75m18.3°E, 35.9°N50841km2-2323.2-3695-13114.2°8.2%
h5263_0000(1901, 1982) px125m57.6°E, 28.8°S39685km2-2299.6-61548074.8°11.2%
h5267_0000(9301, 1314) px75m17.0°E, 36.4°N47984km2-2356.2-4417-8874.4°9.6%
h5281_0000(5252, 1315) px75m56.6°E, 38.3°N27428km2-2083.0-3202987.1°24.7%
h5285_0000(9503, 1447) px75m15.8°E, 36.6°N48208km2-2342.2-4333-9074.2°8.8%
h5286_0000(12437, 2499) px50m84.3°W, 44.7°N51054km2352.5-212431924.1°8.9%
h5288_0000(7205, 989) px75m76.5°E, 26.4°N32079km2-820.7-297214997.9°27.4%
h5299_0000(7368, 1569) px75m55.2°E, 38.8°N38310km2-1278.4-30933546.0°18.1%
h5303_0000(8752, 1349) px75m14.7°E, 36.9°N44190km2-2389.0-4249-10844.3°8.9%
h5304_0000(5767, 2267) px50m85.4°W, 41.9°N21127km21403.9-23231594.5°9.8%
h5306_0000(10740, 1140) px75m74.8°E, 24.6°N49345km2-439.1-345418637.0°22.9%
h5314_0000(6601, 879) px100m5.5°W, 37.9°N45091km2-3626.2-5167-21132.6°2.9%
h5317_0000(5703, 1415) px100m52.6°E, 44.2°N44583km2-2354.1-3417-2294.5°9.9%
h5321_0000(4153, 974) px100m13.9°E, 38.8°N28588km2-2641.5-3894-15343.4°5.8%
h5322_0000(11803, 1319) px75m86.2°W, 37.1°N59678km2899.2-66831424.8°11.9%
h5324_0000(3577, 1087) px75m73.6°E, 30.2°N16795km2-1439.1-3462172410.1°38.4%
h5328_0000(4952, 1353) px100m32.7°E, 43.5°N37536km2-2845.0-37736163.2°5.1%
h5335_0000(6852, 1311) px100m52.1°E, 46.0°N54418km2-2721.0-3605594.2°9.8%
h5339_0000(11202, 1377) px75m12.6°E, 40.0°N60184km2-2815.6-4172-9133.6°6.4%
h5340_0000(12402, 1321) px75m87.4°W, 38.1°N64076km2588.7-106423173.4°6.2%
h5342_0000(12303, 1124) px75m72.7°E, 25.0°N61556km2-85.3-317617305.8°16.5%
h5360_0000(7976, 1248) px75m71.4°E, 28.8°N40686km2-1.4-282717397.9°27.5%
h5376_0000(12049, 1437) px75m89.7°W, 38.1°N64857km2674.9-92424582.9°4.9%
h5378_0000(6071, 977) px100m70.2°E, 29.0°N44808km2137.2-230615146.5°20.9%
h5380_0000(2689, 1598) px75m131.0°W, 44.5°N15263km2-1551.1-2293-10551.8°0.9%
h5383_0000(3176, 1592) px75m71.0°W, 49.0°N19640km2-2274.4-36122374.4°10.8%
h5401_0000(1385, 1211) px100m72.6°W, 48.1°N11121km2-1689.0-3416-3724.9°12.2%
h5405_0000(9603, 2538) px50m111.9°W, 46.6°N38658km21488.0-140553482.3°1.7%
h6395_0000(3753, 762) px100m16.7°W, 30.9°S23456km2464.7-123014644.5°9.3%
h6408_0000(13202, 1385) px75m121.4°E, 35.1°S63518km2891.4-21323863.1°3.7%
h6409_0000(9796, 949) px100m20.4°E, 29.5°S65961km21730.5-81130143.6°6.0%
h6419_0000(3202, 1267) px75m99.5°E, 38.4°S15688km2-921.4-280526446.3°19.8%
h6437_0000(1282, 885) px100m97.2°E, 37.5°S8733km2-1262.9-332530357.3°25.3%
h6465_0000(9817, 1324) px75m169.5°E, 33.4°S57385km21096.9-53530904.5°8.6%
h6486_0000(8681, 1737) px75m143.0°W, 43.7°S50290km22302.547638883.2°5.2%
h6544_0000(2801, 1598) px100m127.9°E, 40.7°S27010km21561.651425753.4°4.8%
h6552_0000(2002, 1306) px125m42.4°E, 45.7°S24423km2294.7-189018554.0°8.2%

The Souness Martian glacier-like forms - looking at the lowest and highest elevation objects

Nov 30, 2016

Colin Souness, in his 2012 paper listed a total of 1309 'glacier-like forms' on the surface of Mars, in the mid-latitudes centred around 40° latitude, found from Mars Reconnaisance Orbiter context camera images.

In my dissertation (version for tablets) I studied descriptive statistics of them, including the distribution by elevation.

Since then, I have produced a web index to the objects, including a Top Trumps page for each object. I below show a table of links to the 30 Souness objects at the lowest and highest elevations. The Mars Express High Resolution Stereo Camera digital terrain model tile is shown where there is coverage, and it is also indicated where there are HiRISE images, or 3d anaglyphs that intersect with the outline of the object. These are linked to from the Top Trump page.

The elevation distribution looks as follows:
Elevation histograms for Souness object extents and head areas, compared with the overall elevation distribution in the coverage of the HRSC DTM tiles used

Slope histograms for Souness object extents and head areas, compared with the overall slope distribution in the coverage of the HRSC DTM tiles used
Showing the ratio of the GLF distribution as a function of elevation and slope / elevation and slope distribution in the HRSC tiles for extents.
The GLF distribution as a function of elevation  / elevation distribution in the HRSC tiles for the head areas.

The GLF distribution as a function of slope  / slope distribution in the HRSC tiles for the head areas.
I noted in the dissertation that that the numbers of glaciers appeared to be depleted below elevations of -3000m relative to Mars datum. There are two types of explanation for this, firstly that they were not formed, or secondly that they were more rapidly ablated. Fewer may have formed in the range -5000 to -3000 due to slope effects, with a large proportion of the these elevations being made up of the flat plains in the northern hemisphere, and the Martian glaciers are preferentially found on slopes. Alternatively in the higher-obliquity epoch, ablation may have been favoured at low elevations, due to higher temperatures, and possibly wind-stripping of debris cover allowing sublimation.

The outliers at the extreme ends of the elevation distribution may be of interest, since they may show something about what limited the distribution of Souness objects on Mars.

There is a secondary peak in the distribution at very low elevations. These could have formed at a later epoch at a lower obliquity in a cooler climate where glacier accumulation was only significant at the lowest elevations.
It is also an interesting question whether the objects at very high elevations formed at the same epoch as the main distribution, or whether these come from an older, more extreme obliquity epoch.

Lowest and highest 30 Souness glacier-like forms

Based on mean elevation of 5km circular radius buffer (from Souness et al. 2012 paper)

Lowest elevation 30 GLFs (buffer mean from Souness catalog):

Catalog numberElevation (m)RegionHRSC DTM tileCentre LatitudeCentre LongitudeArea (sq. km)N HiRISE footprints intersectingN anaglyphs intersecting
1130-6664West of HellasH2613_0000-32.5156.615.6300
1123-6603East of Hellasnone-35.6275.610.8000
1126-6540West of Hellasnone-30.8264.500.7100
1119-6534East of HellasH2195_0000-44.2983.562.8500
1122-6533East of Hellasnone-35.5675.580.7900
1120-6466East of HellasH2195_0000-44.3083.572.9200
1118-6001East of HellasH2631_0001-42.7185.991.3500
1301-5507East of HellasH2631_0001-39.8286.160.7500
1302-5456East of HellasH2631_0001-39.8286.140.8410
193-5431Utopia Planitia and Phlegra Montesnone38.59137.201.0310
1117-5334East of HellasH2631_0001-39.8286.160.7000
1114-5283East of HellasH2609_0000-38.2288.122.2400
1300-5227East of HellasH2631_0001-39.8286.1718.4700
198-5137Utopia Planitia and Phlegra MontesH1526_000038.93116.361.9931
200-5108Utopia Planitia and Phlegra MontesH1526_000039.08116.073.6210
1112-5097East of HellasH0365_0000-40.9790.172.0510
1113-5077East of HellasH0365_0000-40.9990.160.6110
194-5025Utopia Planitia and Phlegra MontesH2878_000040.12120.161.9610
199-5019Utopia Planitia and Phlegra MontesH1526_000039.05116.050.5910
195-5008Utopia Planitia and Phlegra MontesH2878_000040.11120.232.6410
1115-4981East of HellasH2609_0000-38.2188.064.7400
196-4958Utopia Planitia and Phlegra MontesH2878_000040.58120.398.7800
1111-4886East of HellasH0365_0000-40.6290.283.0700
197-4881Utopia Planitia and Phlegra MontesH2878_000040.52120.536.1100
1116-4860East of HellasH2609_0000-38.6287.948.0100
1131-4842West of Hellasnone-35.2051.268.6400
1103-4588East of HellasH0528_0000-38.5494.372.0021
1134-4193West of Hellasnone-35.6148.982.1400
1110-4187East of HellasH0550_0000-36.5190.170.8400
3-4161Deuteronilus MensaeH3253_000038.33-9.762.4100

Highest elevation 30 GLFs (buffer mean from Souness catalog):

Catalog numberElevation (m)RegionHRSC DTM tileCentre LatitudeCentre LongitudeArea (sq. km)N HiRISE footprints intersectingN anaglyphs intersecting
825894Olympus Mons and surrounding areanone41.69-110.671.1600
814139Olympus Mons and surrounding areaH5405_000044.92-111.193.2900
793927Olympus Mons and surrounding areanone38.33-103.580.6710
10343533East of HellasH2356_0002-40.83103.0220.4921
12873444East of HellasH2279_0001-42.76108.159.7100
10433155East of HellasH0451_0000-37.89103.3817.2921
9983134East of HellasH1887_0000-42.03109.5938.6200

Based on mean HRSC DTM elevation of immediate head area (100m radius)

Lowest elevation 30 GLFs (head):

Note that a terminus elevation of 0 is due to the terminus falling in a no data area.
Catalog numberHead elevation (m)Termimus elevation (m)RegionHRSC DTM tileHead LatitudeHead LongitudeArea (sq. km)N HiRISE footprints intersectingN anaglyphs intersecting
1130-6858-7173West of HellasH2613_0000-32.5056.655.6300
1119-6667-6943East of HellasH2195_0000-44.2783.582.8500
1120-6639-6918East of HellasH2195_0000-44.3083.602.9200
1118-5779-6047East of HellasH2631_0001-42.7085.991.3500
1117-5550-5647East of HellasH2631_0001-39.8386.170.7000
1301-5550-5663East of HellasH2631_0001-39.8386.160.7500
1302-5430-5659East of HellasH2631_0001-39.8486.130.8410
198-5251-5718Utopia Planitia and Phlegra MontesH1526_000038.90116.381.9931
1300-5180-5595East of HellasH2631_0001-39.2186.1818.4700
1113-50500East of HellasH0365_0000-40.9990.170.6110
200-4996-5782Utopia Planitia and Phlegra MontesH1526_000039.08116.043.6210
1115-4937-5051East of HellasH2609_0000-38.1988.074.7400
1112-49340East of HellasH0365_0000-40.9790.192.0510
199-4927-5397Utopia Planitia and Phlegra MontesH1526_000039.05116.040.5910
1114-4912-5228East of HellasH2609_0000-38.2288.102.2400
1116-4861-5262East of HellasH2609_0000-38.6587.988.0100
1111-4775-5282East of HellasH0365_0000-40.6190.253.0700
1103-4691-5009East of HellasH0528_0000-38.5594.342.0021
1-4222-4534Deuteronilus MensaeH5314_000037.89-5.9310.9531
2-4149-4530Deuteronilus MensaeH5314_000037.99-5.9618.9531
1110-4037-4049East of HellasH0550_0000-36.5090.180.8400
6-3805-4014Deuteronilus MensaeH1498_000030.59-11.342.7910
192-3772-4407Utopia Planitia and Phlegra MontesH1317_000034.24144.324.3920
3-3746-4196Deuteronilus MensaeH3253_000038.32-9.782.4100
120-3691-3845Olympus Mons and surrounding areaH1258_000134.22-177.334.7100
121-3684-4010Olympus Mons and surrounding areaH1258_000134.22-177.336.5800
4-3677-3914Deuteronilus MensaeH3253_000038.27-9.311.3500
5-3604-4058Deuteronilus MensaeH3253_000040.04-10.362.5000
299-3447-3681Nilosyrtis MensaeH1629_000042.4762.491.4000
1299-3393-4112East of HellasH0550_0000-35.3091.181.6571

Highest elevation 30 GLFs (head):

Catalog numberHead elevation (m)Termimus elevation (m)RegionHRSC DTM tileHead LatitudeHead LongitudeArea (sq. km)N HiRISE footprints intersectingN anaglyphs intersecting
8139143587Olympus Mons and surrounding areaH5405_000044.91-111.213.2900
128736341951East of HellasH2279_0001-42.82108.199.7100
10433367752East of HellasH0451_0000-37.81103.3917.2921
10343225-175East of HellasH2356_0002-40.70103.0120.4921
129030131087East of HellasH2356_0002-41.71104.1221.9810
104228251510East of HellasH0451_0000-37.83103.324.6321
10152800569East of HellasH2345_0000-44.83104.7515.2620

Gul Dukat wins 2374 Galactic Presidential election with Brunt as VP

Nov 12, 2016

Campaign poster showing Gul Dukat and Brunt. Background from APOD by Rogelio Bernal Andreo.
The shock victory of Gul Dukat and Liquidator Brunt in the galactic presidential election has left the Federation wondering if Earth will reconsider plans to leave the Federation following the referendum in which the population narrowly voted to do so.
Although it is now eight Earth years since the Earth voted by 52% to 48% to leave the Federation, the President of Earth has not invoked Article 50 of the planet's membership treaty and is in battle over whether she can do so without a vote in the Planetary Assembly. The Earth orbital and lunar colonies strongly voted remain. The First Minister of Luna is advocating an independence referendum and several asteroid colonies are exploring transferring to Martian jurisdiction which has its own Federation membership.

Losing access to the Federation single market would make Earth more vulnerable to economic exploitation by the Ferengi.

The Leave campaign is now widely regarded as overestimating the amount of dilithium contributed to the Federation budget by Earth.

Government publishes insulting (non-)response to Cornish language funding petition

Nov 11, 2016

On the morning of the second day of the Boundary Commission for England and Cornwall's public hearings relating to the proposed new parliamentary constituencies including a Devonwall constituency, the government has published what it calls a response to the recent petition to restore central government funding for the Cornish language.

I would attend one of the public hearings but I have already responded online and expect the public hearings to be a farce. The issue is not primarily with the Commission but the remit they were given by Government (see my comment on Dick Cole's blog).
However this (non-)response is insulting because it doesn't address any of the issues raised regarding the status of Cornish as a recognised minority language. We are once again treated as second class citizens.

Here are a couple of bar graphs illustrating how much the UK government has been spending each year on the Cornish language in the years 2010 to 2016.
The blue bar is 1200 pixels high in the original image therefore the left hand bar (£108333.33/yr based on £650000 over 6 years) is not even visible in the rendering. It should also be noted that the UK government has funded nuclear weapons since the 1940s whereas the £650000 in 6 years represents the entirety of the UK central government funding for Cornish over more than 300 years since the 1707 Act of Union.

Even on a logarithmic scale it still looks like peanuts.

 The government's response  was so short I can quote it here in full:

The Government has provided Cornwall Council with substantial spending power to allocate resources to their local priorities, including the Cornish language.

Read the response in full
The Government has always been clear that its funding of some £650,000 since 2010 to support the development of the Cornish language was time-limited, and that the Council should seek alternative sources in order to place it on a more sustainable basis. Cornwall Council has a core spending power of £1.7 billion over four years from which they can allocate the necessary resources to local priorities, including the development the Cornish language, if they wish.
Department for Communities and Local Government

This doesn't address any of the issues raised related to the UK signing the European Charter for Regional or Minority Languages or the Framework Convention for the Protection of National Minorities. It is a non-response that can be described as insulting.

This "substantial spending power" is on an annual basis not even 10% of the estimated annual budget for Trident replacement.

Meanwhile the average full-time weekly wage in Kensington is £848.20 whereas in St. Ives constituency it is only £389.20, the 4th lowest in the UK tied with Dwyfor Merionydd. Where is this spending power of which you speak? When are you planning to close the income gap with London?

Cornwall and Devon, with the ESA Sentinel1B synthetic aperture radar satellite

Oct 23, 2016

The European Space Agency operates the pair of Sentinel 1 synthetic aperture radar satellites.

The advantage of radar is that it is not affected by clouds to the same degree that optical remote sensing is,  and there is also useful information gained by the polarisation.

As an example, I downloaded a Sentinel 1B product covering Cornwall and Devon which was taken on 7th October 2016, from the Copernicus data hub.

The type of product I used is the Interferometric Wide Swath mode (further detail).

I used the Sentinel Toolbox to perform orthorectification automatically, and visualise as a RGB with VH polarisation in the red channel, VV in the green, and the ratio between the two in the blue.

The stripmap mode of aquisition, which is less commonly used, provides a higher resolutionof 5m x 5m.

Here is an image from 11th December 2014, with the same colour scheme used.

Returning to the interferometric wide swath mode, overlaying roads and placenames for context. The colour scaling is slightly different in this image, making the green band less strong.
A portion from a Sentinel 2A image from 30th September 2016, using bands 11, 8 and 4 (1610nm, 842nm, 655nm).

The Level 2A product includes a basic pixel level land cover classification - there are some errors here note some cloud shadow has been classified as water or cloud, and spurious snow/ice around Porthtowan.

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