GeographicTypeGeoKey: look-up for 4674 not implemented

[thowse...@gmail.com]

Hi,

I'm processing a couple of LiDAR ALS files collected in Brazil. I'm getting the message:

GeographicTypeGeoKey: look-up for 4674 not implemented.

I think that SIRGAS 2000 EPSGcode 4674 is official in Brasil, so it makes sense for those clouds.

What's the impact of this "lack" in use of lastools stuff?

Tks,

Peter

[Guilherme Braghirolli]

Hello Peter, 

SIRGAS 2000 is currently the official datum in Brazil.

The difference between SIRGAS2000 (4674) and WGS84 (4326) is considered absent by IBGE (Brazilian Geography and Statistic Institute).

"There are currently no transformation parameters between SIRGAS2000 and WGS 84 because they are almost the same, ie, 0 = DX, DY and DZ = 0 = 0" (http://www.ibge.gov.br/home/geociencias/geodesia/pmrg/faq.shtm#11)

Although, there is a small difference between them, as you can see below.

Guilherme Braghirolli

Mestrando PPGPlan - UDESC

Engenheiro Florestal e Técnico Agrimensor

CREA/SC: 123359-0

+55 048 9681-1260

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[Nicolas Cadieux]

Hi,

I have used las2dem with CRS that were not implemented in the past.  In my case, I just needed to specify the raster CRS when I opened it with another software.  There was no other  impact from my perspective.

Nicolas

Envoyé de mon iPad

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[thowse...@gmail.com]

Guilherme, tks for your answer.

Do you think LASTools will automatically consider WGS84 (4326) instead of SIRGAS 2000 (4674)?

Tks again,

Peter

[Martin Isenburg]

Hello,

the only times those EPSG codes are actually used by LAStools are:

* you are reprojecting from EPSG code one to another with las2las

* you are adding the OGC WKT string with las2las

* you want *.prj files auto-produced for your SHP vector outputs

* you want *.prj files auto-produced for your ASC/BIL/XYZ raster outputs

* you want to pass the lasvalidate check

* you want to automatically create KML files to be able to look at your outputs in Google Earth

If LAStools cannot determine what the datum is then WGS84 is used by default, so you should be fine. But maybe we should "hand-tweak" my EPSG code tables to rid you of this error. Could you send a full lasinfo report of one of your LAS / LAZ files in question?

Regards,

Martin @rapidlasso