Kuv tuaj yeem txhim kho qhov siab qhov tseeb hauv TwoNav GPS li cas?

Npaj

Txij li thaum pib ntawm 2021, IGN tau muab kev nkag dawb rau qee qhov ntawm nws cov ntaub ntawv:

• IGN's TOP 25 daim ntawv qhia tsis pub dawb, txawm li cas los xij daim ntawv qhia muaj nyob ntawm Géoporttail yog dawb.
• Databases ntawm IGN altimeter 5 x 5 m yog muaj pub dawb. Cov ntaub ntawv no tso cai rau kev tsim cov qauv digital struts, i.e. daim ntawv qhia qhov siab nrog kab rov tav daws teeb meem ntawm 5 mx 5 m los yog 1 mx 1 m nrog ntsug kev daws teeb meem ntawm 1 m. Los yog lub ntsiab lus zoo rau cov neeg siv uas peb yog.

Kab lus no hauv daim ntawv qhia yog npaj tshwj xeeb rau cov neeg siv ntawm GPS TwoNav thiab Land software.

Nws tsis tuaj yeem cuam tshuam Garmin GPS qhov siab cov ntaub ntawv nyob rau lub sijhawm no.

Dab tsi yog Digital Elevation Model (DTM)

Tus qauv kev nce qib digital (DEM) yog qhov sawv cev peb-dimensional ntawm lub ntiaj teb saum npoo tsim los ntawm cov ntaub ntawv nce. Qhov tseeb ntawm cov ntaub ntawv nce siab (DEM) nyob ntawm:

• Qhov zoo ntawm cov ntaub ntawv qhov siab (qhov tseeb thiab txhais tau tias siv rau kev soj ntsuam),
• Unit cell loj (pixel),
• Hais txog kab rov tav qhov tseeb ntawm qhov chaw ntawm cov kab sib chaws no,
• Qhov tseeb ntawm koj qhov chaw nyob thiab yog li qhov zoo ntawm koj lub GPS, saib txuas lossis koj lub smartphone.

Lub pobzeb lossis pobzeb los ntawm IGN Altimetric database. 5 km x 5 km pobzeb, muaj 1000 × 1000 hlwb lossis 5 mx 5 m hlwb (Saint Gobain Aisne Forest). Qhov kev tshuaj ntsuam no tau npaj mus rau OSM daim ntawv qhia.

DEM yog cov ntaub ntawv uas txhais qhov siab tus nqi ntawm qhov taw tes nyob rau hauv nruab nrab ntawm daim phiaj, nrog rau tag nrho cov saum npoo ntawm daim phiaj ntawm tib qhov siab.

Piv txwv li, 5 x 5 m Aisne BD Alti IGN department file (chaw haujlwm xaiv vim nws loj) tsuas yog qis dua 400 vuas.

Txhua daim phiaj raug txheeb xyuas los ntawm cov kab latitude thiab longitude coordinates.

Qhov me me ntawm daim phiaj loj, qhov tseeb cov ntaub ntawv nce siab. Kev nce siab cov ntsiab lus me dua qhov mesh loj (kev daws teeb meem) tsis quav ntsej.

Qhov me me mesh loj, qhov siab dua qhov tseeb, tab sis qhov loj ntawm cov ntaub ntawv yuav yog, yog li nws yuav siv sij hawm ntau qhov chaw nco thiab nyuaj rau kev ua, uas yuav ua rau qeeb lwm yam kev ua haujlwm.

DEM cov ntaub ntawv loj rau ib chav haujlwm yog li 1Mo rau 25m x 25m, 120Mo rau 5m x 5m.

Cov DEMs siv los ntawm feem ntau cov apps, cov vev xaib, GPS thiab cov neeg siv khoom siv smartphones yog los ntawm cov ntaub ntawv thoob ntiaj teb pub dawb los ntawm NASA.

Qhov kev txiav txim ntawm qhov tseeb ntawm NASA DEM yog lub xov tooj ntawm tes loj ntawm 60m x 90m thiab qib siab ntawm 30m. Cov no yog cov ntaub ntawv nyoos, lawv tsis tau raug kho, thiab feem ntau cov ntaub ntawv yog interpolated, qhov tseeb yog qhov nruab nrab, tej zaum yuav muaj qhov loj. yuam kev.

Qhov no yog ib qho ntawm cov laj thawj rau qhov tsis raug ntsug ntawm GPS, uas piav qhia qhov sib txawv ntawm qhov siab pom ntawm txoj kev taug, nyob ntawm lub vev xaib uas nws tau tuav ntawm, GPS lossis smartphone uas tau sau qhov sib txawv ntawm qhov siab.

• Sonny MNT (saib tom qab hauv phau ntawv qhia no) muaj pub dawb rau Tebchaws Europe nrog lub xov tooj ntawm tes ntawm kwv yees li 25m x 30m. Nws siv cov ntaub ntawv tseeb dua li NASA MNT thiab tau ua haujlwm los daws cov kab mob loj. Nws yog qhov tseeb DEM haum rau kev caij tsheb kauj vab hauv roob, nrog kev ua tau zoo thoob plaws lub tebchaws nyob sab Europe.

Nyob rau hauv daim duab saum toj no, cov pobzeb altimetric (MNT BD Alti IGN 5 x 5) npog cov slag heaps (ze Valenciennes) tau hloov mus rau cov kab contour spaced 2,5 m sib nrug thiab superimposed ntawm daim ntawv qhia IGN. Daim duab tso cai rau koj kom "thov" ntawm qhov zoo ntawm DEM no.

• Lub 5 x 5 m IGN DEM muaj kab rov tav daws teeb meem (cell loj) ntawm 5 x 5 m thiab ntsug kev daws teeb meem ntawm 1 m. Qhov no DEM muab cov struts elevation; qhov siab ntawm cov khoom siv hauv vaj tse (tsev, txuas hniav, hedges, thiab lwm yam) tsis suav nrog. Hauv hav zoov, qhov no yog qhov siab ntawm lub ntiaj teb ntawm ko taw ntawm cov ntoo, qhov chaw ntawm cov dej yog qhov chaw ntawm ntug dej hiav txwv rau tag nrho cov reservoirs loj dua ib hectare.

Kev sib dhos thiab kev teeb tsa ntawm DEM

Txhawm rau kom nrawm dua: Tus neeg siv TwoNav GPS tau sau cov qauv struts digital npog Fabkis siv 5 x 5 m IGN cov ntaub ntawv. Cov no tuaj yeem rub tawm los ntawm cheeb tsam los ntawm qhov chaw pub dawb: CDEM 5 m (RGEALTI).

Rau cov neeg siv, qhov kev sim kom raug los ntsuas qhov kev ntseeg tau ntawm "DEM" yog qhov pom ntawm lub pas dej hauv 3D.

Hauv qab lub pas dej ntawm cov qub forges (Ardennes), qhia hauv 3D los ntawm BD Alti IGN saum toj no thiab BD Alti Sonny hauv qab no. Peb pom tias muaj qhov zoo.

CDEM altimeter maps muab los ntawm TwoNav raws li tus qauv rau lawv GPS lossis LAND software tsis muaj kev ntseeg siab heev.

Yog li, qhov "kev qhia" no muab cov lus qhia siv rau rub tawm "vuas" ntawm cov ntaub ntawv altimetry txhim khu kev qha rau TwoNav GPS thiab LAND software.

Cov ntaub ntawv muaj pub dawb rau:

• Txhua Tebchaws Europe: Sonny Altimetry Database,
• Fabkis: IGN altimetry database.

Koj tuaj yeem tsim cov ntaub ntawv npog lub tebchaws, chav haujlwm lossis thaj chaw thaj chaw nkaus xwb (Slab / pobzeb / Pellet) kom txuag tau siv tau lub cim xeeb lossis siv cov ntaub ntawv me.

Sonny Altimeters Database

Cov qauv 1 '' tau muab faib ua 1 ° x1 ° cov ntaub ntawv chunks thiab muaj nyob rau hauv SRTM (.hgt) hom ntawv nrog lub xovtooj loj ntawm 22 × 31 m nyob ntawm latitude, hom ntawv siv thoob ntiaj teb thiab siv ntau yam kev pab cuam. Lawv raug xaiv los ntawm lawv cov kev tswj hwm, piv txwv li N43E004 (43 ° sab qaum teb latitude, 4 ° sab hnub tuaj longitude).

txheej txheem

1. Txuas mus rau qhov chaw https://data.opendataportal.at/dataset/dtm-france

2. Rub tawm cov vuas sib raug rau lub teb chaws xaiv lossis thaj chaw.

3. Extract cov ntaub ntawv .HGT los ntawm cov downloaded .ZIP cov ntaub ntawv.

4. Hauv av, thauj txhua .HGT cov ntaub ntawv

5. Hauv av, txhua qhov xav tau .hgts qhib, kaw qhov seem.

6. Thov ua "Combine no DEMS", lub sij hawm muab tso ua ke yuav ntev nyob ntawm seb cov vuas luaj li cas (xaiv lub cdem extension) rau .CDEM cov ntaub ntawv uas yuav siv tau rau ntawm Twonav GPS.

OSM "pobzeb" thiab MNT "pobzeb" daim ntawv qhia hauv av, txhua yam yog portable rau GPS thiab 100% dawb!

IGN Altimetry Database

Cov ntaub ntawv no muaj ib daim ntawv teev npe los ntawm department.

txheej txheem

1. Txuas mus rau Geoservices site. Yog tias qhov txuas no tsis ua haujlwm: koj tus browser "tsis muaj FTP nkag": tsis txhob ntshai! Cov neeg siv phau ntawv qhia:
   • Hauv koj cov ntaub ntawv tus thawj tswj hwm:
   • right click "This PC"
   • right click "ntxiv qhov chaw network"
   • Sau qhov chaw nyob «ftp: // RGE_ALTI_ext: [e-mail]» «tsis muaj«»;
   • Lub npe no nkag mus txheeb xyuas nws ex IGN geoservice
   • Xaus cov txheej txheem
   • Tos ob peb feeb rau daim ntawv teev npe hloov tshiab (nws yuav siv li ob peb feeb)
2. Tam sim no koj tau nkag mus rau IGN cov ntaub ntawv:
   • Txoj nyem rau ntawm cov ntaub ntawv koj xav luam.
   • Tom qab ntawd INSERT rau hauv lub hom phiaj directory
   • Lub sijhawm them tuaj yeem ntev!

Daim duab no qhia txog kev ntshuam ntawm Vaucluse 5m x 5m altimeters database. Right click on the file, then copy to the folder and wait for the download.

Tom qab unpacking cov ntaub ntawv "zipped", ib tsob ntoo qauv tau txais. Cov ntaub ntawv sib raug rau txog 400 cov ntaub ntawv cov ntaub ntawv (cov vuas) 5 km x 5 km lossis 1000 × 1000 cells 5 m x 5 m hauv .asc hom (cov ntawv nyeem) rau chav haujlwm.

Cov nplais pobzeb feem ntau npog MTB khiav.

Txhua 5x5 km ntawm tes raug txheeb xyuas los ntawm ib pawg Lambert ua haujlwm 93.

UTM kev tswj hwm ntawm lub ces kaum sab laug ntawm cov pobzeb lossis cov vuas yog x = 52 6940 thiab y = 5494 775:

• 775: qeb qeb (770, 775, 780, ...) ntawm daim ntawv qhia
• 6940: Qib ntawm kab hauv daim ntawv qhia

3. DAB NEEG

4. Hauv cov kauj ruam tom ntej, nrhiav cov ntaub ntawv hauv "data" directory, xaiv tsuas yog thawj cov ntaub ntawv:

5. Qhib ces paub meej tias, lub qhov rais hauv qab no yuav qhib, ceev faj, qhov no yog kauj ruam ilv tshaj plaws :

Xaiv qhov projection Lambert-93 thiab Datum RGF 93 thiab kos lub thawv nyob rau sab laug ces kaum.

Av rho tawm thiab tsim cov ntaub ntawv los ntawm * .asc vuas, uas tuaj yeem siv sijhawm ntev.

Tom qab tsim cov slabs los ntawm DEM hauv SRTM (HGT / DEM) hom ntawv, muaj ntau npaum li lawv muaj cov ntaub ntawv hauv * .asc hom.

6. Av tso cai rau koj "sib txuas" lawv rau hauv ib qho DEM cov ntaub ntawv lossis los ntawm cov pobzeb lossis granule kom haum rau koj cov kev xav tau (nco ntsoov tias cov ntaub ntawv loj tuaj yeem ua rau GPS ua haujlwm qeeb)

Rau kev siv yooj yim, nws yog qhov zoo dua (yeem) los npog tag nrho cov ntawv qhib ua ntej.

Nyob rau hauv daim ntawv qhia zaub mov (saib hauv qab) qhib tag nrho cov ntaub ntawv nyob rau hauv lub * .hdr hom (tsawg kawg voluminous) ntawm imported database cov ntaub ntawv directory (raws li rau yav dhau los ua hauj lwm)

Av qhib HDR cov ntaub ntawv, department DEM yog loaded thiab siv tau

7. Ntawm no koj tuaj yeem siv Ardennes DEM (pob daim ntawv qhia), kom nws yooj yim dua rau siv, peb yuav muab lawv tso rau hauv ib daim ntawv.

Daim ntawv qhia zaub mov:

Ua ke cov DEMs no

Xaiv lub * .cdem hom ntawv thiab npe cov ntaub ntawv DEM.

Kev sib koom ua ke yuav siv sijhawm me ntsis, ntau dua 21 cov ntaub ntawv yuav tsum tau muab sib xyaw. Li no cov lus pom zoo ua haujlwm raws li MNT granules npog koj qhov chaw ua si.

Peb tsim cov qauv digital ntawm Ardennes struts, tsuas yog qhib daim ntawv qhia IGN Geoportal daim ntawv qhia raws li qhia hauv qab no, piv txwv.

Qhov kev ntsuam xyuas yog ua los ntawm ncaj qha qhib UtagawaVTT khiav "Château de Linchamp" tso tawm thaum pib ntawm qhov siab sib txawv ntawm 997m, 981m nrog Sonny DTM ( txheej txheem dhau los) thiab 1034m thaum Av hloov qhov siab ntawm txhua qhov taw tes nrog DTM qhov siab ntawm 5mx5m. .

Kev suav ntawm qib sib txawv los ntawm kev suav cov kab contour ntawm IGN daim ntawv qhia qhia qhov sib txawv ntawm qib 1070 m, uas yog, qhov sib txawv ntawm 3%, uas yog qhov tseeb heev.

Tus nqi ntawm 1070 tseem kwv yees vim nws tsis yog qhov tseem ceeb los xam cov nkhaus ntawm daim duab qhia kev nyem.

Siv cov ntaub ntawv altimetry

MNT.cdem cov ntaub ntawv tuaj yeem siv los ntawm LAND txhawm rau rho tawm qhov siab, xam qhov siab, txoj kab nqes, txoj kev taug kev, thiab ntau dua; thiab rau tag nrho TwoNav GPS li nws txaus los muab cov ntaub ntawv tso rau hauv / daim ntawv qhia npe thiab xaiv nws li map.cdem.

Ib tsab xov xwm blog ntawm qhov siab tsis raug qhia txog qhov teeb meem ntawm qhov chaw nyob thiab qhov siab sib txawv siv GPS, lub hauv paus ntsiab lus tuaj yeem nqa mus rau GPS saib nrog rau cov apps smartphone.

Cov neeg tsim khoom siv ntau txoj hauv kev los "rho tawm" qhov tsis raug uas tau nthuav tawm hauv tsab xov xwm no, lim (tsav qhov nruab nrab) cov ntaub ntawv qhov siab, siv lub ntsuas ntsuas barometric lossis cov qauv hauv av.

GPS qhov siab yog "tsis nrov", piv txwv li hloov pauv ib puag ncig tus nqi nruab nrab, qhov siab barometric nyob ntawm qhov vagaries ntawm barometric siab thiab kub, yog li huab cua thiab DEM cov ntaub ntawv tuaj yeem ua tsis raug.

Hybridization ntawm barometer nrog GPS lossis DEM yog raws li hauv qab no:

• Nyob rau lub sijhawm ntev, qhov kev hloov pauv hauv qhov siab barometric nyob ntawm huab cua (siab thiab kub),
• Nyob rau lub sijhawm ntev, GPS qhov siab yuam kev raug lim tawm,
• Tau ntev, DEM yuam kev zoo ib yam li suab nrov, yog li lawv tau lim tawm.

Hybridization yog hais txog kev xam qhov nruab nrab GPS lossis DEM qhov siab thiab rho tawm qhov siab hloov ntawm nws.

Piv txwv li, hauv 30 feeb dhau los, qhov siab ntawm cov suab nrov lim (GPS lossis MNT) tau nce 100 m; Txawm li cas los xij, nyob rau tib lub sijhawm, qhov siab tshaj plaws qhia los ntawm barometer tau nce 150 meters.

Logically, qhov kev hloov ntawm qhov siab yuav tsum yog tib yam. Kev paub txog cov khoom ntawm cov sensors no ua rau nws muaj peev xwm "hloov" qhov -50 m barometer.

Feem ntau hauv Baro + GPS lossis 3D hom, qhov ntsuas qhov siab tau raug kho, raws li tus neeg taug kev lossis tus neeg nce toj yuav manually, los ntawm kev xa mus rau IGN daim ntawv qhia.

Tshwj xeeb, GPS tsis ntev los no lossis lub xov tooj smartphone tsis ntev los no (zoo) kuaj pom koj (FIX) nrog qhov tseeb ntawm 3,5m hauv kab rov tav dav hlau 90 npaug ntawm 100 thaum txais tos zoo tagnrho.

Kab rov tav "kev ua tau zoo" no sib haum rau mesh loj ntawm 5 mx 5 m lossis 25 mx 25 m thiab kev siv cov DTMs no tso cai rau qhov tseeb ntsug zoo.

Lub DEM qhia qhov siab ntawm hauv av, piv txwv li yog tias koj hla Tarn Valley ntawm Millau viaduct, txoj kev uas tau sau tseg rau ntawm DEM yuav tsum coj koj mus rau hauv qab ntawm lub hav, txawm tias txoj kev tseem nyob ntawm lub viaduct platform. ...

Lwm qhov piv txwv, thaum koj caij tsheb kauj vab hauv roob lossis taug kev ntawm toj roob hauv pes siab, txoj kab rov tav GPS qhov tseeb deteriorates vim lub npog ntsej muag lossis ntau txoj kev cuam tshuam; ces qhov siab muab rau FIX yuav sib haum mus rau qhov siab ntawm ib tug nyob ib sab los yog ntau tshaj slab, li no mus rau sab saum toj los yog mus rau lub hauv paus ntawm lub hav.

Nyob rau hauv rooj plaub ntawm cov ntaub ntawv tsim los ntawm daim phiaj ntawm ib qho chaw loj, qhov siab yuav zoo li qhov nruab nrab nruab nrab ntawm lub hav thiab sab saum toj!

Rau ob qho piv txwv no tab sis raug piv txwv, qhov sib txawv ntawm qhov siab yuav maj mam sib txawv ntawm tus nqi tseeb.

Cov lus pom zoo siv

Kom tsis txhob muaj kev phiv:

• Calibrate lub GPS barometer ntawm qhov siab ntawm koj qhov chaw pib sai ua ntej tawm mus (pom zoo los ntawm txhua lub tuam txhab GPS),
• cia koj GPS ua ob peb FIXES ua ntej pib taug qab kom qhov chaw raug qhov sib tw,
• xaiv hybridization: altitude xam = Barometer + GPS lossis Barometer + 3D.

Yog tias koj qhov kev nce siab tau raug synced rau DEM, koj yuav muaj qhov siab thiab nqes hav zoo heev xws li hauv daim duab hauv qab no, qhov sib txawv tsuas yog 1 meter.

• GPS Trail 2 (72dpi degraded duab capture, 200dpi GPS npo)
• Overlay raster thiab OSM vector map
• Nqe 1: 10
• CDEM 5mx5m BD Alti IGN shading hais txog qhov siab hauv 1m increments.

Cov duab hauv qab no piv cov profile ntawm ob qhov sib npaug 30km lem (ntawm tib lub koob meej), qhov siab ntawm ib qho tau synced nrog IGN DEM thiab lwm yam nrog Sonny DEM, txoj kev khiav hauv baro + hybrid hom 3d.

• Qhov siab ntawm IGN daim ntawv qhia: 275 m.
• Qhov siab suav nrog GPS hauv Hybrid Baro + 3D hom: 295 m (+ 7%)
• Qhov siab suav nrog GPS hauv Hybrid Baro + GPS hom: 297 m (+ 8%).
• Synchronized nce ntawm IGN MNT: 271 m (-1,4%)
• Synchronized nce ntawm Sonny MNT: 255 m (-7%)

"Qhov tseeb" yog tej zaum sab nraum 275m IGN vim qhov nkhaus teeb.

Piv txwv ntawm tsis siv neeg calibration (them nyiaj them) ntawm GPS barometric altimeter thaum txoj kev qhia saum toj no (Original log file los ntawm GPS):

• Tsis muaj ntsug tsub zuj zuj rau xam qhov siab sib txawv: 5 m, (Parametrization yog zoo tib yam rau cov nkhaus ntawm daim ntawv qhia IGN),
• Altitude thaum lub sij hawm calibration / pib dua:
  • GPS 113.7 m
  • Barometric altimeter 115.0 m,
  • Qhov siab MNT 110.2 m (Carte IGN 110 m),
• Iteration (Lub Sijhawm Txiav Txim): 30 feeb
• Kev kho barometric rau 30 feeb tom ntej: - 0.001297