[pdal] Z value change on reprojection in pdal 1.6
Doug Newcomb
newcomb.ttg at gmail.com
Tue Nov 14 07:55:27 PST 2017
Michael,
That seems to have done the trick! I will test against the batch from NOAA
later, but I think that looks like the issue. So this version of pdal is
not keeping the vertical datum by default when reprojecting, and you need
to specify the vertical datum in the projection definition. I can
understand why that might be, but I was assuming that the vertical datum
would carry over by default.
Doug
On Tue, Nov 14, 2017 at 10:07 AM, Smith, Michael ERDC-RDE-CRREL-NH CIV <
Michael.Smith at erdc.dren.mil> wrote:
> Hmm, it might be that pdal is reading the source vertical projection as
> navd88 and if you are reprojecting and not specifying a vertical
> projection, it might be assuming wgs84. You can try specifying the output
> projection as epsg:5070+5703
>
>
>
> Mike
>
>
>
>
>
> --
>
> Michael Smith
>
> Remote Sensing/GIS Center
>
> US Army Corps of Engineers
>
>
>
>
>
> *From: *Doug Newcomb <newcomb.ttg at gmail.com>
> *Date: *Tuesday, November 14, 2017 at 9:58 AM
> *To: *Michael Smith <michael.smith.erdc at gmail.com>
> *Cc: *pdal <pdal at lists.osgeo.org>
> *Subject: *Re: [pdal] Z value change on reprojection in pdal 1.6
>
>
>
> Micheal,
>
> The problem is the z values of all of the point values are have been
> changed. I had created a raster from the mean value of the ground points
> from the pdal reprojected data. I then went back to NOAA's site and
> selected a small subset to compare and had their engine deliver the points
> in Albers Meters Conus NAVD88. I imported the points to create a raster
> in the same way and then subtraced the Z value of the pdal reprojected
> points from the NOAA reprojected points. The height values vary by 32-36 m
> ( see below) .
>
>
>
> That was why I was asking if I had missed a step that ensured that the Z
> values stayed at the Geoid12A/12B/NAVD88 values.
>
>
>
> Tue Nov 14 09:45:55 2017)
>
>
> r.info map=noaa_pdal_vert_diff_m at dnewcomb
>
>
> +----------------------------------------------------------
> ------------------+
>
> | Map: noaa_pdal_vert_diff_m at dnewcom Date: Tue Nov 14 09:36:19
> 2017 |
>
> | Mapset: dnewcomb Login of Creator: dnewcomb
> |
>
> | Location: seva_albers
> |
>
> | DataBase: /data2/grass70_data
> |
>
> | Title: noaa_pdal_vert_diff_m
> |
>
> | Timestamp: none
> |
>
> |----------------------------------------------------------
> ------------------|
>
> |
> |
>
> | Type of Map: raster Number of Categories: 0
> |
>
> | Data Type: FCELL
> |
>
> | Rows: 12465
> |
>
> | Columns: 20411
> |
>
> | Total Cells: 254423115
> |
>
> | Projection: NAD83 / Conus Albers
> |
>
> | N: 1687158.47979 S: 1668162.01936 Res: 1.52398399
> |
>
> | E: 1653024.11274 W: 1621917.96408 Res: 1.52398945
> |
>
> | Range of data: min = 32.17395 max = 36.06071
> |
>
> |
> |
>
> | Data Description:
> |
>
> | generated by r.mapcalc
> |
>
> |
> |
>
> | Comments:
> |
>
> | 2635_mean_ground_1_524_test_from_noaa_meters at dnewcomb -
> |
>
> | 2635_mean_ground_1_524 at PERMANENT
> |
>
> |
> |
>
> +----------------------------------------------------------
> ------------------+
>
>
>
>
>
>
>
> Doug
>
>
>
> On Mon, Nov 13, 2017 at 8:20 PM, Michael Smith <
> michael.smith.erdc at gmail.com> wrote:
>
> Doug,
>
>
>
> It looks like perhaps the header metadata is not correct, which is what I
> think you are seeing from lasinfo. When you inspected the Decimal Degrees
> file it shows
>
>
>
> "bbox":
>
> {
>
> "maxx": -76.2527221,
>
> "maxy": 37.9068695,
>
> "maxz": -5.777103023,
>
> "minx": -76.2571767,
>
> "miny": 37.9028129,
>
> "minz": -35.71281856
>
> },
>
>
>
> which match your albers output.
>
>
>
>
>
> --
>
> Michael Smith
>
> Remote Sensing/GIS Center
>
> US Army Corps of Engineers
>
>
>
>
>
> *From: *pdal <pdal-bounces at lists.osgeo.org> on behalf of Doug Newcomb <
> newcomb.ttg at gmail.com>
> *Date: *Monday, November 13, 2017 at 8:14 PM
> *To: *pdal <pdal at lists.osgeo.org>
> *Subject: *[pdal] Z value change on reprojection in pdal 1.6
>
>
>
> Ok,
>
> Finally diving into pdal more deeply. I installed the docker instance of
> pdal 1.6 and tried a bit of command line reprojection:
>
>
>
> I downloaded some data from the NOAA website and re-projected from
> Decimal Degrees to Albers Meters Conus ( EPSG:5070)
>
> pdal translate /data/20100503_LAS_S23_1836_10.laz
> /data/albers_20100503_LAS_S23_1836_10.laz -f filters.reprojection
> --filters.reprojection.out_srs="EPSG:5070"
>
>
>
> For the input data , lasinfo gives :
>
>
>
>
>
> Minimum and Maximum Attributes (min,max)
>
> ---------------------------------------------------------
>
> Min X, Y, Z: -76.2571767, 37.9028129, 0.024
>
> Max X, Y, Z: -76.2527221, 37.9068695, 29.966
>
> Bounding Box: -76.2571767, 37.9028129, -76.2527221,
> 37.9068695
>
>
>
> for the output laz file, lasinfo gives:
>
>
>
> Minimum and Maximum Attributes (min,max)
>
> ---------------------------------------------------------
>
> Min X, Y, Z: 1707096.44, 1829911.69, -35.72
>
> Max X, Y, Z: 1707557.20, 1830350.12, -5.77
>
> Bounding Box: 1707096.44, 1829911.69, 1707557.20,
> 1830350.12
>
>
>
>
>
> pdal info for the input file gives:
>
>
>
>
>
> {
>
> "filename": "\/data\/20100503_LAS_S23_1836_10.laz",
>
> "pdal_version": "1.6.0 (git-version: 94ad83)",
>
> "stats":
>
> {
>
> "bbox":
>
> {
>
> "EPSG:4326":
>
> {
>
> "bbox":
>
> {
>
> "maxx": -76.2527221,
>
> "maxy": 37.9068695,
>
> "maxz": -5.777103023,
>
> "minx": -76.2571767,
>
> "miny": 37.9028129,
>
> "minz": -35.71281856
>
> },
>
> "boundary": {
>
> "coordinates" : [
>
> [
>
> [ -76.257176700000002, 37.902812900000001 ],
>
> [ -76.257176700000002, 37.906869499999999 ],
>
> [ -76.2527221, 37.906869499999999 ],
>
> [ -76.2527221, 37.902812900000001 ],
>
> [ -76.257176700000002, 37.902812900000001 ]
>
> ]
>
> ],
>
> "type" : "Polygon"
>
> }
>
>
>
> },
>
> "native":
>
> {
>
> "bbox":
>
> {
>
> "maxx": -76.2527221,
>
> "maxy": 37.9068695,
>
> "maxz": 29.966,
>
> "minx": -76.2571767,
>
> "miny": 37.9028129,
>
> "minz": 0.024
>
> },
>
> "boundary": {
>
>
>
> pdal info on the output laz file gives:
>
> {
>
> "filename": "\/data\/albers_20100503_LAS_S23_1836_10.laz",
>
> "pdal_version": "1.6.0 (git-version: 94ad83)",
>
> "stats":
>
> {
>
> "bbox":
>
> {
>
> "EPSG:4326":
>
> {
>
> "bbox":
>
> {
>
> "maxx": -76.25185156,
>
> "maxy": 37.90686951,
>
> "maxz": -5.77,
>
> "minx": -76.25806657,
>
> "miny": 37.9021939,
>
> "minz": -35.72
>
> },
>
> "boundary": {
>
> "coordinates" : [
>
> [
>
> [ -76.258066569999997, 37.903041880000004 ],
>
> [ -76.257028300000002, 37.90686951 ],
>
> [ -76.251851560000006, 37.90602148 ],
>
> [ -76.252890100000002, 37.9021939 ],
>
> [ -76.258066569999997, 37.903041880000004 ]
>
> ]
>
> ],
>
> "type" : "Polygon"
>
> }
>
>
>
> },
>
> "native":
>
> {
>
> "bbox":
>
> {
>
> "maxx": 1707557.2,
>
> "maxy": 1830350.12,
>
> "maxz": -5.77,
>
> "minx": 1707096.44,
>
> "miny": 1829911.69,
>
> "minz": -35.72
>
> },
>
> "boundary": {
>
>
>
>
>
> Am I missing a switch in the translate command?
>
>
>
>
>
> Doug
>
>
>
>
>
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>
>
>
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