From 670b06900a49fb84bfffcf2781b6a48af4866b26 Mon Sep 17 00:00:00 2001
From: Andreas Madsen <amwebdk@gmail.com>
Date: Wed, 14 Oct 2015 15:39:49 +0200
Subject: [PATCH] [draft] kortforsyningen, dhm

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+
+# DHM - height model
+
+**description**
+
+This dataset contains height information about Denmark. The raw data files
+are points collected using the LiDAR technology, they are available in
+the `PUNKTSKY` directory.
+
+There are also DSM (digital surface model) in the `DSM` directory. And DTM
+(digital terrain model) in the `DTM` directory. That is a processed version
+of the raw data `PUNKTSKY`
+
+**source**
+
+ftp://ftp.kortforsyningen.dk/dhm_danmarks_hoejdemodel/
+
+**format**
+
+* `PUNKTSKY`: `.zip` file following a naming convention, contains multiply `.laz` files.
+* `DSM` and `DTM`: `.zip` file following a naming convention, contains multiply `.tif` files.
+
+In each directory is a shapefile (in `GRID/grid_punktsky_SHP_UTM32-ETRS89.zip`)
+dividing the country up into blocks. The shapefile contains information about
+the location of the block and name of the `.zip` file that contains the height
+information.
+
+The filenames have the format `${model}_${lat1}_${long1}_${format}_UTM32-ETRS89.zip`.
+Each `.zip` files then contains the actual data files divided up into another
+level of blocks. Those filenames have the format `${model}_1km_${lat1}${lat2}_${long1}${long2}.${format}`
+
+The `lat2` and long `long2` forms a 10 by 10 grid. But sometimes files are
+missing. We presume this is because no interesting data exists there
+(just water).
+
+For example the zipfile `DTM_605_66_TIF_UTM32-ETRS89.zip` would have the files:
+
+```
+dtm_1km_6059_660.tif dtm_1km_6059_661.tif ... dtm_1km_6059_669.tif
+dtm_1km_6058_660.tif dtm_1km_6058_661.tif ... dtm_1km_6058_669.tif
+.                    .                    .   .
+.                    .                    .   .
+.                    .                    .   .
+dtm_1km_6050_660.tif dtm_1km_6050_661.tif ... dtm_1km_6050_669.tif
+```
+
+Each pixel the average height in a 40cm x 40cm rect. Each data file (`.tif` or
+`.laz`) has a resolution of 2500 x 2500 pixels. Thus each data file describes
+a 1km x 1km block.
+
+**completeness**
+
+Currently the data have only been collected for Fyn and Sjælland.