Model Elevasi Digital Permukaan Bumi (DEM)

Transkripsi

1 Model Elevasi Digital Permukaan Bumi (DEM) APLIKASI LANJUT MATERI PEMBUATAN PROFIL DAN KONTOUR Lokasi manakah yang masih bisa dikembangkan untuk lokasi permukiman? Berapa luas hutan yang masih ada? 1

2 PETA adalah : Gambaran Permukaan Bumi Yang diproyeksikan ke bidang datar dengan skala tertentu Apa yang dimaksud dengan permukaan bumi? hutan permukiman jalan relief sungai 2

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4 08/05/2014 PENYAJIAN DATA KETINGGIAN DALAM BENTUK KONTUR DAN SHADING Perbesaran Vertikal 1 kali A B Ketinggian ANALISIS PROFIL PENAMPANG MELINTANG Jarak 4

5 ANALISIS LERENG/GRADIEN Kemiringan lereng/slope sering Disebut dengan gradien Ketinggian A Perbesaran Vertikal 1 kali B Jarak MENGHITUNG GRADIEN 100 C C 25 Selisih nilai antara dua kontur di A dan di C A Jarak horisontal di peta x skala B B Misal jarak B - C adalah 2 cm di peta pada skala , maka jarak di lapangan sama dengan 2 cm x = cm = 1000 m Beda Tinggi B-C adalah = 75 meter. Maka kemiringan lereng adalah 75 / 1000 = 0,075 derajad atau 75/1000 x 100 % = 7,5 % 5

6 Apa itu DEM Digital Elevation Model: What it looks like Lay a grid over some part of the world and find the average elevation in each cell 6

7 Cell Definition 13 cell size (cell value) cell The size of a cell is in either: meters, feet, degrees, or arc seconds DEMs and DTMs 14 Some definitions DSM (Digital Surface Model) Set of regularly or irregularly spaced of surface vaue It contains information about trend of surface DEM (Digital Elevation Model) set of regularly or irregularly spaced height values no other information DTM (Digital Terrain Model) set of regularly or irregularly spaced height values but, with other information about terrain surface ridge lines, spot heights, troughs, coast/shore lines, drainage lines, faults, peaks, pits, passes, etc. 7

8 DEMs and TINs 15 DEM with sample points TIN based on same sample points Advantages/disadvantages DEMs: accept data direct from digital altitude matrices must be resampled if irregular data used may miss complex topographic features may include redundant data in low relief areas less complex and CPU intensive TINs: accept randomly sampled data without resampling accept linear features such as contours and breaklines (ridges and troughs) accept point features (spot heights and peaks) vary density of sample points according to terrain complexity 16 8

9 Sumber Data DEM Survei Lapangan Data Analisis Penginderaan Jauh Foto Udara (Stereo) Photogrammetry Foto Stereo Citra Satelit Imagegrammetry (Stereo) Shuttle Imaging (Stereo) Imagegrammetry (Stereo) dan Radargrammetry Radar Radargrammetry (interferomettry Differential Interferometry) INSAR / IFSAR, DINSAR LIDAR Point Cloud Analysis (advanced) Sumber lain : DEM Data Sources Shuttle Radar Topography Mission (SRTM) 30m DEMs from 1:24,000 scale map 1 National Elevation Dataset 3" (100m) DEMs from 1:250,000 scale maps 30" DEM of the earth (GTOPO30) 9

10 Shuttle Radar Topography Mission (SRTM) 1 arc-second elevation data for the United States, 3 arcsecond data for the globe Produced by radar measurements from a Shuttle mission, Feb 11-22, data/obtainingdata. html SRTM Coverage 56 S to 60 N 10

11 30m DEMs Best resolution standardized data source available for the US Coverage of the country is incomplete Data by 7.5 map sheets in UTM projection Link for US e/usgs_dem Link for Texas National Elevation Dataset Seamless 1 DEM for the US in 1 x 1 blocks Compiled by synthesizing the 30m DEM s from 1:24,000 scale maps Link to website ed/ 11

12 Seamless Data Distribution Coverage of 30m, 1 and 3" DEMs 1 and 3 DEMs 30m DEM 1º º 12

13 3 DEMs Derived by US Defence Mapping Agency, available from USGS for the whole US Data in geographic coordinates by 1;250,000 map sheet names (1ºx 1º) cells in (1ºx 2º) maps Needs to be projected to planar coordinates Link 30m Cell Size 100m 13

14 30" DEM GTOPO30 Produced by USGS from 3" grids and Digital Chart of the World topography Coverage complete for the earth Projected cell size is 1km Data must be projected before use Link GTOPO30 Source: 14

15 GARIS BESAR KEGIATAN SURVEI TANAH Peta Dasar Digitasi Peta Mosaik Foto Persiapan Peta Kerja Foto Udara Analisis Landform Peta Landform Poligon Satuan Peta Tanah Digital SURVEI LAPANGAN Data Lahan Lereng Batuan Permukaan Singkapan Batuan Bahaya Banjir & Erosi Morfologi Tanah Drainase Bahan Kasar Basis Data Lahan & Tanah Data Sosek Data Iklim Contoh Tanah Basis Data Sosek Basis Data Iklim Analisis Laboratorium ph, C-Organik, KTK liat, KB, Tekstur Curah Hujan Temperatur Kelembaban Basis Data Laboratorium CITRA SATELIT Peta Liputan Lahan Klasifikasi Hasil Evaluasi u/ SPT Campuran per LUT Peta Kesesuaian Lahan Adaptasi ke Peta Digital Hasil Evaluasi Evaluasi Lahan (Program Ales) Pengolahan Data Produksi Karakteristik Lahan Karakteristik Lahan Persyaratan Penggunaan Lahan POTENSI DEGRADASI Longsor, Erosi, dll PENGEMBANGAN PENGGUNAAN LAHAN 15