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handle pj_transform HUGE_VAL results (aka inf)

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- turns out pj_transform will not always return an error code for
   failed transforms and may instead just set values as HUGE_VAL
 - this commit handles this and calls it an error by return false
   from forward/backward

Arguably if `point_count` > 1 some values might be correctly transformed
while others might be HUGE_VAL. For the purposes of Mapnik we will consider
any HUGE_VAL as an error because we have no way to handle partial failures.
This commit is contained in:
Dane Springmeyer 2015-06-10 18:34:11 -07:00
parent 8e30a89522
commit 352586e9d7
2 changed files with 100 additions and 2 deletions
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14
src/proj_transform.cpp
View file

@ -163,6 +163,13 @@ bool proj_transform::forward (double * x, double * y , double * z, int point_cou
return false;
}
for(int j=0; j<point_count; j++) {
if (x[j] == HUGE_VAL || y[j] == HUGE_VAL)
{
return false;
}
}
if (is_dest_longlat_)
{
int i;
@ -205,6 +212,13 @@ bool proj_transform::backward (double * x, double * y , double * z, int point_co
return false;
}
for(int j=0; j<point_count; j++) {
if (x[j] == HUGE_VAL || y[j] == HUGE_VAL)
{
return false;
}
}
if (is_source_longlat_)
{
int i;

88
test/unit/projection/proj_transform.cpp
View file

@ -4,6 +4,12 @@
#include <mapnik/proj_transform.hpp>
#include <mapnik/box2d.hpp>
#ifdef MAPNIK_USE_PROJ4
// proj4
#include <proj_api.h>
#endif
TEST_CASE("projection transform")
{
@ -33,6 +39,84 @@ SECTION("Test bounding box transforms - 4326 to 3857")
CHECK(bbox.maxx() == Approx(maxx));
CHECK(bbox.maxy() == Approx(maxy));
} // END SECTION
}
} // END TEST CASE
#if defined(MAPNIK_USE_PROJ4) && PJ_VERSION >= 480
SECTION("test pj_transform failure behavior")
{
mapnik::projection proj_4269("+init=epsg:4269");
mapnik::projection proj_3857("+init=epsg:3857");
mapnik::proj_transform prj_trans(proj_4269, proj_3857);
mapnik::proj_transform prj_trans2(proj_3857, proj_4269);
auto proj_ctx0 = pj_ctx_alloc();
REQUIRE( proj_ctx0 != nullptr );
auto proj0 = pj_init_plus_ctx(proj_ctx0, proj_4269.params().c_str());
REQUIRE( proj0 != nullptr );
auto proj_ctx1 = pj_ctx_alloc();
REQUIRE( proj_ctx1 != nullptr );
auto proj1 = pj_init_plus_ctx(proj_ctx1, proj_3857.params().c_str());
REQUIRE( proj1 != nullptr );
// first test valid values directly against proj
double x = -180.0;
double y = -60.0;
x *= DEG_TO_RAD;
y *= DEG_TO_RAD;
CHECK( x == Approx(-3.1415926536) );
CHECK( y == Approx(-1.0471975512) );
CHECK( 0 == pj_transform(proj0, proj1, 1, 0, &x, &y, nullptr) );
CHECK( x == Approx(-20037508.3427892439) );
CHECK( y == Approx(-8399737.8896366451) );
// now test mapnik class
double x0 = -180.0;
double y0 = -60.0;
CHECK( prj_trans.forward(&x0,&y0,nullptr,1,1) );
CHECK( x0 == Approx(-20037508.3427892439) );
CHECK( y0 == Approx(-8399737.8896366451) );
double x1 = -180.0;
double y1 = -60.0;
CHECK( prj_trans2.backward(&x1,&y1,nullptr,1,1) );
CHECK( x1 == Approx(-20037508.3427892439) );
CHECK( y1 == Approx(-8399737.8896366451) );
// longitude value outside the value range for mercator
x = -181.0;
y = -91.0;
x *= DEG_TO_RAD;
y *= DEG_TO_RAD;
CHECK( x == Approx(-3.1590459461) );
CHECK( y == Approx(-1.5882496193) );
CHECK( 0 == pj_transform(proj0, proj1, 1, 0, &x, &y, nullptr) );
CHECK( std::isinf(x) );
CHECK( std::isinf(y) );
// now test mapnik class
double x2 = -181.0;
double y2 = -91.0;
CHECK( false == prj_trans.forward(&x2,&y2,nullptr,1,1) );
CHECK( std::isinf(x2) );
CHECK( std::isinf(y2) );
double x3 = -181.0;
double y3 = -91.0;
CHECK( false == prj_trans2.backward(&x3,&y3,nullptr,1,1) );
CHECK( std::isinf(x3) );
CHECK( std::isinf(y3) );
// cleanup
pj_ctx_free(proj_ctx0);
proj_ctx0 = nullptr;
pj_free(proj0);
proj0 = nullptr;
pj_ctx_free(proj_ctx1);
proj_ctx1 = nullptr;
pj_free(proj1);
proj1 = nullptr;
}
#endif
}